Term
| What are the names of the arteries supplying the cortex of the kidney? (Start with the renal artery and continue with the 3 successively smaller arteries that supply nephrons). |
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Definition
| Abdominal aorta to Renal Arteries to segmental artery to interlobular arteris to arcuate artery to interlobular artery to afferent arteriole to glomerulus to efferent artiole to peritubular capillaries (cortical nephron) or vasa recta (juxtamedullary nephron) |
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Term
| What are the four main components of a nephron? |
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Definition
| Renal corpuscle, Proximal tubule, Loop of Henle, Distal Tubule (Not Collecting duct?) |
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Term
| What are the four types of cells that make up the structure of the renal corpuscle? |
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Definition
Bowman's capsule has an outer parietal layer composed of simple squamous epithelium. The visceral layer, composed of modified simple squamous epithelium, is lined by podocytes.
Podocytes have foot processes, pedicels, that wrap around glomerular capillaries. These pedicels interdigitate with pedicels of adjacent podocytes forming filtration slits.
The glomerulus is a small tuft of capillaries containing two cell types. Endothelial cells, which have large fenestrae, are not covered by diaphragms. Mesangial cells are modified smooth muscle cells that lie between the capillaries and the glomerulus. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and cytokines. Mesangial cells also have phagocytic activity, removing proteins and other molecules trapped in the glomerular basement membrane or filtration barrier |
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Term
| What structures are present in the innermost portion of the renal medulla? How are they different histologically? |
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Definition
Loop of henle: The epithelium of the Thick segment is low simple cuboidal epithelium. The epithelium of the Thin segment is simple squamous.[4]
They can be distinguished from the vasa recta (blood vessels have endothelium) by the absence of blood, and they can be distinguished from the thick ascending limb by the thickness of the epithelium.[5]
collecting ducts has simple cuboidal epithelium composed of dark intercalated cells that transport bicarbonate and hydrogen ions and light cells that contain the single cilium on the apical surface and also possess vesicles with aquaporin 2 that they release to insert on their apical membrane in response to ADH |
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Term
| What are 3 components of the filtration barrier found in the glomerulus? |
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Definition
| Podocytes, fenestrated Capillary, filtration slits |
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Term
| What are the 3 structural differences between cells of the proximal tubule and cells of the distal tubule? |
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Definition
| (1) Proximal tubule has tall simple cuboidal epithelium with long apical microvilli, Distal convoluted tubule has simple cuboidal epithelium not as tall as proximal tubule. (2) single cilium on distal convoluted tubule cells not present on proximal tubule cells. (3) distal convoluted tubule has cells of juxtaglumerula apparatus that release renin in response to drop in plasma NaCl, not present in proximal tubule. (Also proximal tubule contains megalin which breaks down peptides in the early proximal tubule so that it can be reabsorbed) |
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Term
| How does antidiuretic hormone modulate the permeability to water of the collecting ducts? |
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Definition
| The collecting duct is impermeable to water so water cannot leave the lumen of the collecting duct unless auquaporin channels are present. ADH function is to enhance AQUA 2 to resorbp the water into the plasma and avoid "mictritution" |
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Term
| What are the 2 main components of the juxtaglomerular apparatus? What are their respective functions? |
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Definition
Juxtaglomerular cells + Macula Densa = Juxtaglomerular Apparatus
Specialized region of the distal tubule near the glomerulus:
Macula Densa cells: taller, act as sensors for Na+ and Cl- in urine
Adjacent to Juxtaglomerular Cells (specialized muscle cells) of the
afferent arteriole that secrete RENIN |
|
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Term
| What is a unique ultrastructural feature of the transitional epithelium of the bladder? How does this feature contribute to adaptation to bladder filling and stretch? |
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Definition
Adaptation of luminal cells of epithelium to stretch that occurs when bladder
Fills Stretch stimulates the movement of cytoplasmic vesicles to the plasma
membrane. These vesicles can rapidly increase the surface area of the cells to adapt to a flattened cell shape. Inserted membranous plaques contain a protein called uroplakin |
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Term
| In what direction, relative to the central vein, does blood flow within the liver? |
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Definition
| Blood flows toward the central vein from hepatic portal vein and hepatic artery. Bile goes to the opposite direction from central vein to bile duct. |
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Term
| What are the components of a portal triad? How may they be distinguished from one another? |
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Definition
Hepatic portal vein –usually centrally located and largest of the three components
Hepatic artery – surrounded by a noticeable layer of smooth muscle
Bile Duct – contains the simple cuboidal epithelium |
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Term
| What are the ultrastructural characteristics of a hepatocyte? How can the features of a hepatocyte surface bordering a bile canaliculus be distinguished from the surface bordering a sinusoid? |
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Definition
| Hepatocytes may contain one or two nuclei, they are separated by sinusoids, have bile canaliculi running through them to deliver bile to the bile duct. The hepatocyte surface bordering a sinusoid contain endothelial cells and in between the endothelial cells and the hepatocyte exists a space of Disse which house the so called Ito cells. |
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Term
| What features of a sinusoid distinguish it from other blood vessels? |
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Definition
| Its size and its DISCONTINUOUS membrane |
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Term
| Where is the space of Dissé located? |
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Definition
| Located between the sinusoid’s fenestrated endothelium (lacks basement membrane) and the hepatocytes |
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Term
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Definition
| Phagocytize red blood cells because they are aggregates of monocytes. Note that since they have phagocytic functions, they are located in the sinuisods |
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Term
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Definition
| Produce collagen, store lipds, and store vitamin A |
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Term
| How are sugars taken up into hepatocytes? What molecule resulting from protein catabolism is secreted from the liver into the bloodstream? What protein carries cholesterol away from the liver? |
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Definition
| Sugars are taken up into hepatocytes using GLUT2 glucose transporters. Ammonia(which forms urea) is secreted from the liver as a byproduct of protein catabolism (hepatic encephalopathy can result from liver failure), Lipoproteins carry cholesterol away from the liver (they are also synthesized by the liver) |
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Term
| What is the function of bile salts? From what molecules are they synthesized? |
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Definition
| Bile salts emulsify fats. They are synthesized from cholic acid and taurine. |
|
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Term
Compare the histological organization of the gall bladder wall with that of
the small intestine. What differences that distinguish the two organs? |
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Definition
| Do it yourself. But one key difference is the presence of lymphatic glands in the small intestines and the presence of absorptive cells that exist in the small intestine and not in the Gall bladder. |
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Term
| What histological features of the following pancreatic cells (acinar, centroacinar, intercalated duct cells) allow them to be distinguished from each other? |
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Definition
Acinar – highly polarized, basophilic on the end due to rER and eosinophilic apically due to zymogen granules
Centroacinar – located in the center of the acinar (light staining)
Intercalated duct cells – simple cuboidal epithelium
Excretory duct cells – stratified columnar epithelium |
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Term
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Definition
Regulates blood glucose, stores glycogen
Secretes bile into intestine
Synthesizes many blood proteins
Detoxifies ingested chemicals |
|
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Term
| In liver damage (Cirrhosis)what happens? |
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Definition
| Ito cells overproduce collagen and disturb liver blood flow |
|
|
Term
| Synthesis of Plasma Proteins in the liver are............... what? |
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Definition
Albumin
Clotting Proteins
IGF-1 (growth factor)
C-reactive protein (produced in response to inflammation in the body; a good marker of coronary artery disease) |
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Term
| JAUNDICE is caused by what? |
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Definition
results from a buildup of bilirubin. Bilirubin is a byproduct of heme, and carried by albumin (albumin made in liver)
ALSO In alcoholics (>3 mixed drinks, or >6-pack of beer per day), acetaldehyde can cause liver damage and CIRRHOSIS |
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Term
| What histological features of ductuli efferentes allow them to be distinguished from the epididymus? |
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Definition
| The ductuli efferents have an irregularly shaped lumen with irregularly arranged epithelium while the epididymis has a pseudostratified columnar epithelium with sterocilia at the apical border) |
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Term
| What is an unusual histological feature of the vas deferens? How does this feature relate to the function of the vas deferens? |
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Definition
| The vas deferens is surrounded by A LOT of smooth muscle. When the smooth muscle contracts it helps in propelling the sperm forward into the ejaculatory duct which is a continuation of the vas deferens. |
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Term
| What is an identifying feature of the prostate that distinguishes it from other glands? |
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Definition
The prostate gland has secretory acini that possess pseudostratified columnar epithelium, LCT and smooth muscle. The main identifying feature would be the prostate concretions which are condensed calcified secretory material.
One protein, a serine protease, is an enzyme called PROSTATE SPECIFIC ANTIGEN
Elevated production of PSA causes PSA to be detectable in blood, and may be an indicator of prostate carcinoma |
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Term
| What is an unusual ultrastructural feature of the Sertoli cell? How does this feature relate to the blood-testis barrier? |
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Definition
| The sertoli cells have numerous tight junctions. The tight junctions prevent material from entering the lumen of the testis thus they help form the blood testis barrier. |
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Term
| . How is a distinctive ultrastructural feature of a Leydig cell relate to its function? |
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Definition
| Leydig cells have a tubular shaped cristae in their mitochondria which indicates that their main function is steroid synthesis (=testosterone), which uses LH as precusor |
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Term
| How does Viagra correct erectile dysfunction? |
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Definition
| Viagra acts by inhibiting phosphodiesterase which inhibits cGMP. By allowing cGMP to be in excess, NO can bind to cGMP and cause vasodialation and relaxation of venous channels allowing blood to rush to the penis and cause an erection despite lowered levels of testosterone. |
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Term
| From which organelle is the acrosome of a spermatozoon derived? |
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Definition
| The golgi apparatus. vesicles move from the Golgi stack and adhere to one pole of the nucleus to fuse into a large acrosomal vesicle |
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Term
| What organelle is particularly abundant in the mid-piece of a spermatozoon? |
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Definition
| Mitochondria; which is needed to provide energy for the flagella |
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Term
| Which cell within a seminiferous tubule is in a haploid state? |
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Definition
Spermatids
Spermatocyte – meiosis to give rise to spermatids
Spermatogonia - mitosis |
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Term
| Sertoli cells secrete what? |
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Definition
| Sulfated glycoproteins, Androgen binding protein,Transferrin, nutrients, Inhibin & the control of pituitary FSH (negative feedback) |
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Term
| Describe how the immune-lymphatic system is organized into primary lymphoid organs (bone marrow and thymus) and secondary lymphoid organs ( lymph nodes, spleen, tonsils, aggregates of lymphoid tissue in digestive tract (gut—associated lymphoid tissue (GALT), in the lung (bronchial-associated lymphoid tissue (BALT) , mucous associated lymphoid tissue (MALT) . |
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Definition
A. Primary lymphoid tissue
1. thymus: site of maturation of immature T lymphocytes
2. bone marrow:
- home of lymphocyte stem cells
- site of maturation of B lymphocytes
B. Secondary lymphoid tissue
1. lymph nodes:
- found at the junction of major lymph vessels
- are the site where both T and B lymphocytes may interact with antigen and antigen presenting cells (APC) form the circulating lymph and undergo activation and cell division
2. spleen: location where t and B lymphocytes may interact with blood-borne antigen and undergo stimulation and cell dvision
3. MALT (mucosal associated lymphoid tissue):
- tonsils and adenoids
- lymphoid aggregates: respond to antigens entering the body thru the mucosae of the GI, respiratory, and genitourinary tracts
*GALT (gut associated lymphoid tissue)
*BALT (bronchial associated lymphoid tissue) |
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Term
| Describe the main function of the immune-lymphatic system in protecting the body against pathogens and various antigens (bacteria, viruses and parasites). |
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Definition
The main function of the immune-lymphatic system is to:
A. protect the body against pathogens, antigens
B. provide a defense mechanism against invaders (immune response)
C. have the ability to distinguish between self-antigens and foreign antigens |
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Term
| Be able to describe the basis for the body’s ability to mount a defense mechanism (immune response) in distinguishing between self-antigens and non-self (foreign) antigens. |
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Definition
| The body has developed three main lines of defense against organisms that may invade the body and cause harm: protective surface mechanisms (lymphoid tissues), the innate immune system, and the adaptive immune system. |
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Term
| List and describe the two key cell components (B and T cells) of the immune system, the site of origin and differentiation of each cell type. |
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Definition
A. B Lymphocytes
1. derived from stem cells in the bone marrow and also mature there
2. stimulated B cells mature into plasma cells that synthesize large amounts of antibody (immunoglobulin: IgA, M, G, E, D)
- these antibodies circulate in the blood and lymph streams and attach to foreign antigens to mark them for destruction by other immune cells
B. T Lymphocytes
1. derived from stem cells in the bone marrow
2. immature T lymphocytes migrate from the bone marrow tot the thymus where they develop into mature T lymphocytes
3. divided into several functional subsets
a. T helper cells (TH cells): ‘help’ other cells to perform their effector functions by secreting a variety of mediators (interleukins)
b. cytotoxic T cells (TC cells): kill virus-infected and some cancer cells; can become killer T cells
4. two major roles in the immune defense
a. regulatory T cells are essential for orchestrating the response of an elaborate system of different types of immune cells
b. helper T cells to start making antibodies, activate other T cells and inmmune scavenger (macrophages) and influence which type antibody is produced |
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Term
| List the accessory (macrophages, dendritic, follicular) cells of the immune-lymphatic system and describe the functions of each cell type in the immune-lymphatic system. |
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Definition
A. Dendritic cells: patrol the body surfaces and phagocytose invading pathogens(Langerhans cells of the epidermis)
B. Follicular dendritic cells: found in the lymph nodules; bind antibody-antigen complexes to their surface without prior processing
C. Macrophages: monocytic-derived cells; engulfs antigens, processes it thru lysosomal components, break it down so it can be taken up the other lymph cells |
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Term
| List the two types of immunity (innate or natural and adaptive or acquired) and describe the conditions for the activation of each type. |
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Definition
A. innate (natural) immune system
1. provides a rapid reaction to infections
2. responds in the same magnitude each time the same pathogen is encountered (no learning)
3. end results:
a. release of molecules toxic to microorganisms
b. phagocytosis and intracellular killing of organisms
c. natural killer cells: kill virus-infected or malignant cells
4. causes inflammation
5. cellular components: neutrophils, basophils, macrophages, mast cells
B. adaptive (acquired) immune system
1. characterized by the ability to learn, so that the second and subsequent encounters with a pathogen elicit a greater, are specific and faster response
- basis for life-long immunity to certain infections after an initial episode or vaccination
2. depends on cell division to produce a large number of lymphocytes with a specificity for a particular pathogen
3. lymphocytes kill or disable pathogens by a
a. cellular response (T lymphocytes or T cells)
b. humoral response (B lymphocytes or B cells) |
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Term
| Be able to identify and describe differences between lymphatic nodules and lymph nodes, pharyngeal and palatine tonsils, spleen and thymus. |
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Definition
A. Lymph nodes vs. nodules
1. nodes:
a. located along the course of lymphatic drainage,encapsulated filters of lymph
b. have a convex side where afferent lymphatic vessels enter and a concave depression thru which blood vessels and nerves enter and the efferent lymphatic vessel leave
2. nodule:
a. small localized collection of lymphoid tissue
b. differs from a node in that it is much smaller and doesn’t have a well-defined connective tissue capsule as a boundary; it also doesn’t function as a filter because it is not located along a lymphatic vessel
B. Pharyngeal vs. palatine tonsils
1. pharyngeal
2. palatine tonsils: large non-encapsulated aggregations of lymphocytes
C. Thymus vs. spleen
1. Thymus:
a. flattened lymphoid organ located in the upper anterior mediastinum and lower part of the neck
b. has a highly cellular outer cortex and a less cellular central medulla
2. Spleen:
a. large lymphoid tissue situated in the left upper part of the abdomen
b. consists of white pulp (nodules) and red pulp (matrix)
c. performs the same function the blood that lymph organs perform for lymph |
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Term
| Describe how the structure of the thymus is built around epithelial cell, lymphocytes and blood vessels and its function in the production of T lymphocytes. In addition, be able to explain the steps of how the thymus “educates” T-cells, including the role of the blood-thymus barrier. What is meant by “double-positive,” “double-negative” and “single-positive” T cells? |
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Definition
A. Structure:
1. the epithelial cells provide a mechanical supporting framework for the lymphocyte population
a. cortical epithelial cells promote T cell differentiation and proliferation
b. epithelial cells secrete a number of hormones that regulate T cells maturation and proliferation within the thymus, other lymphoid organs and tissues
2. the inner surfaces of the thymic capsule and septa are invested by a continuous layer of thymic epithelial cells are resting on a basement membrane
3. epithelium also forms sheaths around the blood vessels, creating a barrier to the entry of antigenic material into the thymic parenchyma (blood-thymus barrier)
B. Functions
1. Processing immature thymocytes derived from bone marrow into mature T lymphocytes (educating T cells)
a. precursor cells entering the thymus form the bone marrow lack surface molecules typical of mature T cells (thymus cell receptor (TCR) and CD4 and CD8 co-receptors)
= double-negative T cells: these cells are found in the subcapsular cortex region of the thymus
b. T cells begin to rearrange the genes encoding TCR and express both CD4 and CD8 coreceptors by the same cell
= double-positive T cells: these cells are seen deeper in the cortex of the thymus
c. T cells whose receptors bind self-MHC molecules lose expression of either or CD8 and increase the level of expression of TCR
= mature single-positive T cells: these cells are seen in the medulla of the thymus
2. Proliferation of clones of T cells to supply circulating lymphocyte pool and peripheral tissue
3. Development of immunological self-tolerance (more than 98% of maturing cells die by apoptosis within the thymus, and any are self-reactive)
4. Secretion of hormones and cytokines that regulate T cell maturation, proliferation and function within the thymus and peripheral lymphoid tissues |
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Term
| Describe the structural components of the spleen and how the various structures contribute and participate in facilitating the filtration of blood. Describe the differences between OPEN vs. CLOSED pathways for blood filtration in the spleen. Outline the functions of each type of lymphoid tissue/organ and identify the cellular and vascular elements that make possible these varied functions. |
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Definition
A. Structure
1. receives a rich blood supply from a single artery (splenic artery) and is drained by a single vein (splenic vein) into the hepatic portal system
2. central arteries: larger arteries surrounded by a fibrocollangenous sheath
a. have a cylindrical cuff of lymphoid tissue around them (PALS- periarteriolar lymphoid sheath) consisting of mainly TH cells
b. give off a number of short branches, penicilliary arteries (PA), which terminate in 2-3 sheathed capillaries (SC)
- SC are small blind-ending capillaries with no endothelial lining but are surrounded instead by an aggregate of macrophages
- the blood arriving at an SC must travel thru this wall of macrophages before entering the red pulp
B. Open vs. Closed pathways for blood filtration
1. open circulation: the capillaries discharge openly into the meshwork of a reticular fibrous framework; the blood must pass this meshwork before reaching the sinusoids
*Splenic artery˃ trabecular artery˃ central artery ˃ penicillar artery˃ splenic cords˃ splenic sinusoid˃ trabecular vein˃ splenic vein
2. closed circulation: the capillaries empty directly into the sinusoids
*Splenic artery˃ trabecular artery˃ central artery˃ penicillar artery˃ splenic sinusoids˃ trabecular vein˃ splenic vein
C. Function:
1. production of immunological responses against blood-borne antigens
2. removal of particulate matter and aged and defective blood cells, particularly erythrocytes, from circulation
3. hemopoiesis in the normal fetus and adults with certain diseases |
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Term
| After completing the laboratory exercises of the lymphatic system, you should be able to different lymphatic tissues and organs in light microscopic and electron microscopic images. |
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Definition
| D.D.S. = DO it your DAM SELF |
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Term
| List and distinguish the differences between diffuse and nodular lymphatic tissue. |
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Definition
|
|
Term
| Identify red and white pulp in sections of spleen and describe their structural makeup. |
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Definition
A. red pulp: most consists of loose tissue supported by reticulin fibers permeated by capillaries terminating as sheathed capillaries
1. they remove particulate matter and aged and deformed erythrocytes from blood
- defective cells are less deformable and thus unable to negotiate the narrow slits in the sinusoidal basement membrane
-trapped cells are removed by the macrophages of the sheathed capillaries
B. white pulp: consists of two types
1. T cell: typically forms an eccentric cylindrical sheath around a central artery and containing small lymphocytes mainly of the T helper subset
2. B cell: form follicles usually located in the vicinity of the arteriole |
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Term
| Identify and describe the structural features of venous sinusoids in the red pulp of the spleen that provide for the selective uptake of flexible red blood cells while denying the uptake of rigid ones. |
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Definition
| Venous sinusoids are lined by elongated, spindle shaped epithelial cells (stave cells) lying parallel to the long axis of the sinuses. Slits occur in between the endothelial cells, the endothelial basement membrane being discontinuous over the slits. Blood cells, especially viable erythrocytes, squeeze between the stave cells to reach the venous sinuses; these drain into progressively larger vessels that converge to form the splenic vein. The more rigid, or defective, erythrocytes cannot squeeze thru this slits and get caught and are destroyed by the macrophages. |
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Term
| Be able to identify and describe the structural features of each region of the GI Tract (esophagus, stomach, small intestine and large intestine). |
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Definition
Esophagus
Mucosa – non-keratinized stratified squamous epithelium, Lamina propria, muscularis mucosa (spiral and not always seen), cardiac glands but only near sotomach.
Submucosa – submucosal glands, contains BVs and nerves, venous sinuses, excretory ducts
Muscularis externa – Skeletal muscle in upper third, skeletal and smooth muscle mixture in the middle third, smooth muscle in lower third
Adventitia/ Serosa – several layers of connective tissue (suspensory function)
Stomach
Mucosa – simple columnar epithelium, gastric glands (different in different regions of the stomarch – fundic gland, cardiac glands, pyloric glands)
Submucosa – no submucosal glands
Muscularis – large muscularis externa
Small Intestine (mucosa, submucosa, muscularis, serosa/peritoneium)
Duodenum:
Mucosa – simple columnar epithelium, villi with a leaf like shape, crypts of lieberkuhn, muscularis mucosa.
Submucosa – Mucus secreteing Brunner’s glands, excretory ducts, nerves (meisner’s plexus) and BVs
Muscularis externa – longitudinal and circular layer with auerbach’s plexus in between.
Jejunum:
Mucosa – villi have finger like projections, plicae circularis very extensive in mucosa and submucosa, everything else same as duodenum
Submucosa – no submucoasl glands, crypts of lieberkuhn extend all the way here.
Muscularis externa – longitudinal and circular layer with auerbach’s plexus in between.
Ileum:
Mucosa –simple columnar epithelium, villi are shorter compared to jejunum, location of M Cells (antigen transporting cells)
Submucosa – Peyer’s patches extend throughout lamina propria and submucosa.
Muscularis externa – longitudinal and circular layer with auerbach’s plexus in between. |
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Term
|
Definition
Mucosa – non-keratinized stratified squamous epithelium, Lamina propria, muscularis mucosa (spiral and not always seen), cardiac glands but only near sotomach.
Submucosa – submucosal glands, contains BVs and nerves, venous sinuses, excretory ducts
Muscularis externa – Skeletal muscle in upper third, skeletal and smooth muscle mixture in the middle third, smooth muscle in lower third
Adventitia/ Serosa – several layers of connective tissue (suspensory function) |
|
|
Term
|
Definition
Mucosa – simple columnar epithelium, gastric glands (different in different regions of the stomarch – fundic gland, cardiac glands, pyloric glands)
Submucosa – no submucosal glands
Muscularis – large muscularis externa |
|
|
Term
|
Definition
Mucosa – simple columnar epithelium, villi with a leaf like shape, crypts of lieberkuhn, muscularis mucosa.
Submucosa – Mucus secreteing Brunner’s glands, excretory ducts, nerves (meisner’s plexus) and BVs
Muscularis externa – longitudinal and circular layer with auerbach’s plexus in between. |
|
|
Term
|
Definition
Mucosa – villi have finger like projections, plicae circularis very extensive in mucosa and submucosa, everything else same as duodenum
Submucosa – no submucoasl glands, crypts of lieberkuhn extend all the way here.
Muscularis externa – longitudinal and circular layer with auerbach’s plexus in between. |
|
|
Term
|
Definition
Mucosa –simple columnar epithelium, villi are shorter compared to jejunum, location of M Cells (antigen transporting cells)
Submucosa – Peyer’s patches extend throughout lamina propria and submucosa.
Muscularis externa – longitudinal and circular layer with auerbach’s plexus in between. |
|
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Term
| Describe the main functions of the: esophagus, stomach , small and large intestines. |
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Definition
Esophagus – conduct food from oral cavity to the stomach
Stomach – completes fragmentation of food and initiates digestion
Small Intestines – Digestion and main absorption occurs
Large intestines – water absorption |
|
|
Term
| Identify and describe the four distinct functional layers of the gastrointestinal tract: Mucosa, submucosa, muscularis propria and adventitia. |
|
Definition
Mucosa – made up of 3 components:
1. Epithelium – invaginates to form glands that extend into lamina propria
2. Lamina propria – made up of loose connective tissue (lymphoid cells (plasma cells, lymphocytes, plasma cells, macropahges and follicular dendritic cells), nodular tissue)
3. Muscularis mucosa – smooth muscle layers
Submucosa – made up of blood vessels, nerves, loose connective tissue and lymphatic vessels
Muscularis externa – longitudinal and circular layer of smooth muscle with auerbach’s plexus in between. Inner layer circular layer – reduces the size of the tube: outer longitudinal layer shortens the tube.
Adventitia – several layers of connective tissue surrounding G.I continuous with the surrounding connective tissue – acts to suspend the G.I tract |
|
|
Term
| Identify and describe the basic tissue structure for the following layers of the GI tract: |
|
Definition
a. Mucosa: Epithelium (type –stratified squamous epithelium (non-keratinized ) starting at esophagus – simple columnar as you progress further down)
b. Submucosa: Connective tissue (DICT), vascular plexus (meissner’s plexus), Glands @ duodenum (brunner’s) and esophagus (esophageal)
c. Muscularis Mucosae: Meissner’s plexus
d. Muscularis Externa: Inner circular muscles, Outer longitudinal muscles, Auerbach’s plexus
e. Serosa /Adventitia: Connective Tissue, Mesothelium |
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Term
| Describe the tissue layers of the esophagus and the glands it contains, and indicate the function of these glands. Be able to identify the esophagus and its layers in appropriatediagrams, light microscopic slides or photographs. Describe how the muscularis changes from upper to middle to lower esophagus. |
|
Definition
Mucosa – non-keratinized stratified squamous epithelium, Lamina propria (LCT), muscularis mucosa (spiral and not always seen), cardiac glands but only near sotomach.
Submucosa – DICT, submucosal glands, contains BVs and nerves, venous sinuses, excretory ducts
Muscularis externa – Skeletal muscle in upper third, skeletal and smooth muscle mixture in the middle third, smooth muscle in lower third
Adventitia/ Serosa – several layers of connective tissue (suspensory function |
|
|
Term
| Describe the tissue layers of the stomach. |
|
Definition
Mucosa – simple columnar epithelium, gastric glands (different in different regions of the stomarch – fundic gland, cardiac glands (mucous secreting), pyloric glands (mucous secreting))
Submucosa – no submucosal glands, DICT, nerves, blood vessels
Muscularis – large muscularis externa |
|
|
Term
| Describe the histological features and functions of surface mucous cells, mucous neck cells, parietal cells, chief cells and enteroendocrine cells. Indicate where each of these is located. Be able to recognize surface mucous cells, parietal cells, chief cells and enteroendocrine cells in micrographs. |
|
Definition
Surface mucous cells – forms protective mucous blanket and bicarbonate buffer to protect lining of stomach. Oval shaped nucleus with stored mucous in multiple droplets
Mucous neck cells – secrete mucous under vagal stimulation only: shorter than surface mucous cells
Parietal cells – secrete HCL and intrinsic factor: stain intensely eosinophilic due to membrane mitochondria #
Chief cells – secrete proteins (pepsinogen which is converted to pepsin: basophilic staining (numerous rER).
Enteroendocrine cells – secretes gastrin, cholecystokinin, secretin, gastrin inhibitory peptides (k cells): largest endocrine organ in the body. Found mostly near the base of glands.
Enteroendocrine washed out with H&E and secretory granules with TEM.
(1) regulation of water, electrolyte metabolism and enzyme secretion
(2) Regulation of gastrointestinal motility & mucosal growth
(3) Stimulate the release of other peptide hormones |
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Term
| Describe the ultrastructure of the parietal cell, and the dynamic role of the tubulovesicles and intracellular canaliculi in this cell. Describe the process by which HCl is generated. |
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Definition
| Eosinophilic round cells with nucleus in the middle. It has Gastrin, histamine and acetylcholine receptors in the basal lamin. The intracellular tubulovesicles fuse with the intracellular canaliculi in response to parasympathetic stimulation and the hormone gastrin. This fusion leads to the secretion of acid. (?) |
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Term
| Name the cells that secrete intrinsic factor, and indicate the function of this factor. |
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Definition
| Parietal cells intrinsic factor promotes the absorption of vitamin B12 |
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Term
| Explain role of bicarbonate released by the surface mucous cells. Indicate where bicarbonate is released from parietal cells, and indicate what happens to this bicarbonate. Describe the role of bicarbonate released by parietal cells. |
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Definition
| The bicarbonate released by surface mucous cells acts to buffer and protects the lining of the stomach from its acidity. The bicarbonate released by the parietal cells enters fenestrated blood capillaries in the lamina propria and flow towards surface cells. It diffuses across mucus to cell blankets to increase pH. |
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Term
| Name the different cell types found in the intestinal epithelium and glands, and give their locations and identifying features. |
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Definition
Enterocytes (absorptptive) – found in intestinal epithelium, they are tall columnar absorptive cells
Goblet cells – found in the intestinal epithelium, they are pale staining circular cells
Paneth cells – (antimicrobial immunity- defensin, lysozyme,TNF-alpha) found at the base of the intestinal glands (crypts). Stain intensely eosinophilic due to secretory granules
Enteroendocrine cells – stains eosinophilic found at the base of crypt. Has a lighter staining cytoplasm than paneth cells. (secretin, gastrin, cholecystokinin)
Stem cells – found base of intestinal glands (crypts) divide continuously to replace all these cells. |
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Term
| Describe the main histological differences between the duodenum, jejunum and ileum |
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Definition
Duodenum – submucosal glands (brunner’s glands)
Jejunum – long fingerlike microvilli, well developed plicae circularis
Ileum – M cells, peyer’s patches (lymphoid tissue |
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Term
| Describe the features that increase the surface area of the small intestine, and indicate how the large intestine differs in this regard. |
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Definition
| The small intestine contains four degrees of folding to increase surface area (plicae circularis, villus, crypts of liberkuhn, microvilli).The main feature that increases small intestine SA is the villi. The large intestines lack villi. |
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Term
| Indicate what lacteals are, where they are found, and their function. Describe the process of fat absorption. |
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Definition
| Lacteals are specialized lymphatic vesicles found in the villi of small intestine. They uptake and transport lipoprotein and chylomicrons. Large fat droplet comes in, it is emulsified by bile salts and pancreatic lipases into micelles, the micelles are further broken down into monoglycerides and FFA which are taken to the sER for processing. They are then shipped to the golgi which packages them into vesicles as chylomicrons which are then taken up by the lacteals. |
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Term
| Describe the organization of the Peyer’s patch and its function. Indicate what special cell type is found in the Peyer’s patch surface epithelium and what its function is. |
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Definition
| Peyer’s patches are lymphoid follicles with germinal centers. M cells line the peyer’s patch surface cells and it takes up luminal antigens and presents it to APCs via lymphocytes in the M cells. |
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Term
| Indicate the roles played by the surface absorptive cell microvilli in absorption and digestion. |
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Definition
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Term
| Indicate what are Brunner’s glands are, where are they located, the purpose of their secretions and the place in the GI tract where they are found. |
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Definition
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Term
| Describe the main functions of the large intestine, and ways in which it differs histologically from the small intestine. List the cells that are present in the surface epithelium and glands, and the location of these cells. |
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Definition
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Term
| Describe what special features are present in the anal canal and anus relative to the rest of the large intestine. |
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Definition
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Term
| Describe a distinguishing histological feature of the appendix. |
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Definition
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Term
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Definition
| stored by the liver; produced by sER in the liver |
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Term
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Definition
| receptors that transport glucose from the intestinal mucosal cell into the portal circulation |
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Term
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Definition
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Term
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Definition
poorly soluble breakdown product of heme metabolism in other organs
- is carried to the liver bound to albumin
- must be conjugated to glucuronic acid (by sER enzymes) to make it water soluble and excretable into the bile
- Jaundice results form a buildup of bilirubin |
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Term
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Definition
: toxic end product of alcohol metabolism by the hepatocytes
- created by excess alcohol dehydrogenase activity |
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Term
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Definition
| water soluble end product that results from detoxification of molecules (barbiturates, steroids, bilirubin) and is excreted into the bile |
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Term
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Definition
| inactive form of an enzyme; the acinar cells of the pancreas contain eosinophilic zymogen granules that are located apically (toward the lumen) |
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Term
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Definition
: immotile cell syndrome
- missing dynein arms or microtubules
- cilia cannot move mucus out of the lungs (towards throat) |
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Term
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Definition
supporting cells of the olfactory epithelium
- provide metabolic and physical support for the olfactory cells
- tall columnar cells with microvilli; nuclei located apically |
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Term
| BALT (bronchus associated lymph tissue): |
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Definition
| small concentrations of lymphoid tissue in the lung |
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Term
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Definition
- combination of severe bronchoconstriction due to bronchial smooth muscle contraction and the production of particularly thick mucus
- caused by a combination of genetic and environmental factors (immune response against allergens) |
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Term
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Definition
- made of phospholipids, GAGs, and proteins
- reduces surface tension, facilitates the expansion, and prevents the collapse of alveoli |
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Term
| Type I and II pneumocytes: |
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Definition
Type I: lines the alveoli; site of gas exchange
- Type II: produces surfactant; can differentiate into Type I pneumocytes in response to damage to the alveolar lining |
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Term
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Definition
- causes the progressive destruction of the alveolar ducts, sacs, and alveoli, leading to the permanent dilation of the air spaces but reduction of the surface area for gas exchange VIA ELASTASE (break down of elastic fibers)
- loss of elastic tissue support for the bronchioles, leading to their collapse and air trapping |
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Term
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Definition
| combination of emphysema, chronic bronchitis, and asthma |
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Term
| Alpha-1-antitrypsin/ elastase |
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Definition
- alpha-1-antitrypsin: protease inhibitor; protects tissues from enzymes of inflammatory cells, especially neutrophils elastase
- elastase breaks down elastin, which contributes to the elasticity if the lungs
- in the absence of alpha-1-antitrypsin, elastase breaks down elastin resulting in respiratory complications such as emphysema or COPD |
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Term
| NRDS/ hyaline membrane (neonatal respiratory distress syndrome) |
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Definition
| - caused by insufficient development of type II cells, leading to insufficient surfactant production or a genetic problem with the production of surfactant associated proteins |
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Term
| steps involved with neonatal respiratory distress syndrome |
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Definition
1. surfactant coat is not present or produced in low amounts in a premature infant
2. the alveolar tension increases
3. hypoventilation causes low oxygen (hypoxemia) and rentention of CO2
4. this leads to pulmonary hypoperfusion
5. which leads to pulmonary endothelial cell damage, which causes fibrin and serum proteins to be secreted
6. after time, these components (along with cellular debris, red blood cells, neutrophils, and macrophages) combine to form hyaline membranes.
- These line and fill the air space and block gas exchange
- blood passing thru is unable to pick up oxygen or unload carbon dioxide |
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Term
| Heparin sulfate (urinary section) |
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Definition
- Podocalyxin: integral membrane protein found on the basal surface of podocytes
- it can affect the function of the actin cytoskeleton
- if it is deleted, podocytes fail to form foot processes |
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Term
| Megalin and tubulovesicles (urinary) |
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Definition
| tubulovesicles capture peptides for degradation in lysosomes (peptides are bound to a protein called megalin) |
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Term
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Definition
| protein found in the collecting duct principal cells and intercellular vesicles; reabsorbs water from the urine |
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Term
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Definition
angiotensinogen ------ angiotensin I ------ angiotensin II (potent vasoconstrictor) which also stimulates the secretion of aldosterone from the adrenal cortex; controls blood pressure
From Angiotensinogen to Angiotensin I; Renin enzyme allows rxn
From Angiotensin I to Angiotensin II; ACE (Angiotensin converting enzyme) allows the reaction to go forward |
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Term
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Definition
endocrine product of the kidney; produced by peritubular fibroblasts
- induced by hypoxia
- stimulates production of red blood cells in bone marrow
- can be administered to cancer patients after chemo to improve RBC counts |
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Term
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Definition
acts on the kidney to improve retention of sodium (and therefore water) by the body
- secretion is stimulated by angiotensin II |
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Term
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Definition
| WT-1 is a stimulatory factor that causes renal tumors (Wilm’s tumor) when mutated and overactive |
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Term
| Polycystic kidney disease (polycystin): |
|
Definition
causes increasing kidney malfunction that becomes prominent by age 40
- characterized by outgrowths from normal tubules that enlarge into huge, fluid filled cysts
- 1 in 1000 people
- caused by polycystin 1 or 2: codes for a protein that localizes to single cilia in renal tubule cells; kidney cells with abnormal or missing cilia appear to become dysfunctional and cause the formation of cysts |
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Term
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Definition
| secreted by Sertoli cells; a TGF-β like molecule that inhibits pituitary FSH secretion |
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Term
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Definition
| metabolite of the Sertoli cells; Sertoli cells take up glucose from the bloodstream, metabolize it to lactate and export lactate to germ cells as a nutrient fuel |
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Term
| Functions of Prostate gland. |
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Definition
-Secrete proteins that help maintain fluidity of semen
-One protein, a serine protease, is an enzyme called PROSTATE SPECIFIC ANTIGEN
-Elevated production of PSA causes PSA to be detectable in blood, and may be an indicator of prostate carcinoma |
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Term
| PSA (prostate specific antigen) |
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Definition
One protein, a serine protease, is an enzyme called PROSTATE SPECIFIC ANTIGEN
-Elevated production of PSA causes PSA to be detectable in blood, and may be an indicator of prostate carcinoma |
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Term
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Definition
| The former activates the interstitial cells of Leydig that release testosterone, whereas FSH induces the Sertoli cells to produce adenylate cyclase, which, via a cAMP intermediary, stimulates the production of androgen-binding protein (ABP). Testosterone binds to ABP, and the complex is released into the lumen of the seminiferous tubule, where the elevated testosterone concentration enhances spermatogenesis. |
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Term
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Definition
| small peptide; replaces histone proteins in nucleosomes in the nucleus of developing sperm |
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Term
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Definition
| long microvilli located on the epididymis (don’t move) |
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Term
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Definition
inherited disease (1 in 2500 people)
- causes there an abnormal chloride transporter
- epididymis becomes blocked or fails to develop causing sterility |
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Term
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Definition
| *Viagra is an inhibitor of phosphodiesterase, an enzyme that degrades cGMP. cGMP causes relaxation and dilation of venous channels. |
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Term
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Definition
- Sertoli cells respond to FSH by stimulating the development of germ cells and ABP
- Leydig cells respond to LH by synthesizing testosterone |
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Term
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Definition
crystals found in the cytoplasm of Leydig cells
- composed of an uncharacterized protein aggregate
- function unknown |
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Term
| Nostrils or Nares:what time of epithelium? |
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Definition
- external surface: keratinized stratified squamous epithelium
- hair |
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Term
| in the nose: the route of epithelium type as you descend to the lungs? |
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Definition
| keratinized non-keratinized strat. squa. respiratory epithelium (pseudostratified ciliated columnar epithelium with goblet cells) |
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Term
| Where and what is the function of Bowman's gland? |
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Definition
| Is the site of the Olfactory epithelium; and it secretes serous |
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Term
| What type of cartilage is associated with the epiglottis and what's its epithelium type? |
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Definition
Elastic cartilage
anterior surface and upper part of posterior surface covered
with stratified squamous nonkeratinized epithelium
(lingual surface)
lower, more protected part covered with pseudostratified
ciliated columnar epithelium with goblet cells
(pharyngeal surface) |
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Term
| Trachealis muscle, where is it and what? |
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Definition
fibroelastic ligament and bundle of smooth muscle
*Its the connector of the horseshoe hyaline cart. at trachea |
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Term
| Epithelium transition from Bronchi to Bronchioles........ is what? |
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Definition
simple ciliated columnar to simple cubodial non-cialated epithelium
*note; there is no goblet cells at bronchioles |
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Term
| Clara cells do what and where are they? |
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Definition
Located Bronchiole and serous secretory cells (Clara cells have no cilia) are present in epithelial lining (secrete GAGs that protect bronchiolar lining), dome-shaped
*release chloride and proteases |
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Term
| another name of Type I alveolar cells |
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Definition
|
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Term
| another name for Type II alveolar cells? |
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Definition
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Term
| Surfactant comes from where? what is it? and its components of that cell type. |
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Definition
It comes from Type II alveolar cells (septal cells), which contain phospholipids, proteins and GAG's.
Type II; has lamellar bodies to store surfactant |
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Term
| Alveolar dust cells are what? |
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Definition
| Wandering macrophages that remove debris and stimulate fibrosis at the alveolar space |
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Term
| Alveolar-Capillary Barrier |
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Definition
-Alveolar-Capillary Barrier, Blood-Air Barrier, 0.5 µm thick
-Exchange of gas from alveoli to blood
-4 Layers of membrane to cross
1) alveolar epithelial wall of type I cells
2) alveolar epithelial basement membrane
3) capillary basement membrane
4) endothelial cells of capillary
*Vast surface area = handball court |
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Term
| Define the terms: lobule, conducting division and respiratory division. |
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Definition
Lobule – a small segment or lobe
Conducting division – brings gas down to the lungs
Respiratory division –division where gas exchange takes place |
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Term
| Desribe the histological organization of the extrapulmonary parts of the respiratory system. |
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Definition
Mucosa
a)Epithelium (KSSE, NKSSE, PSCC)
b)Lamina propria
c)Submucosa: Glands, bv, nerves, smooth mus
d)Cartilage: Hyaline cartilage in trachea |
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Term
| Describe the specialized histological features of each of the extrapulmonary parts of the respiratory system. |
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Definition
Nasal cavity – outer external area is KSSE, vestibule is NKSSE and olfactory area is PSCC (respiratory epithelium)
Epiglottis – Lingula surface is NKSSE, and pharyngeal side is PSCC; Lamina propria is LCT with elastic fibers, supported by Elastic cartilage
Larynx – true vocal cords lined by NKSSE with skeletal muscle beneath it; false vocal cords lined with PSCC
Trachea – C-shaped horseshoe ring, surrounded by hyaline cartilage ring, first appearance of smooth muscle connecting the hyaline cartilage |
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Term
| Compare the olfactory mucosa to the respiratory mucosa. |
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Definition
Olfactory mucosa – pseudostratified ciliated columnar epithelium, NO GOBLET CELLS, microvilli are on the supporting cells (sustentacular cells), basal cells, Lamina propria
Respiratory mucosa – pseudostratified ciliated columnar epithelium, goblet cells(?), it has basal short germinating cells, endocrine cells of kulchitsky, Lamina propria |
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Term
| Describe the histological structures of the bronchi, bronchioles, respiratory bronchioles, alveolar ducts, alveoli, pulmonary arteries and pulmonary veins. |
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Definition
Bronchi – folded mucosa (respiratory epithelium), muscularis mucosa (sm), submucosa (serious acini), and cartilage plate (scattered hyaline cartilage)
Brionchioles – mucosa (simple columnar to simple cuboidal epithelium, Lamina proproia (smooth muscle and elastic fibers), no glands, cartilage or goblet cells), connective tissue adventitia, clara cells
Respiratory bronchioles – (look into detail)
Alveolar ducts – simple squamous epithelium, no clara cells
Alveoli – simple squamous epithelium, type I and II cells, macrophages |
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Term
| Describe the blood-air barrier and identify its components in micrographs or diagrams. |
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Definition
| The blood-air barrier is the barrier that O2 has to travel through in order to get to the blood. The components that make up the barrier include the Type I cells of the alveoli, basement membrane of the alveoli epithelium, the basement membrane of the capillary endothelial cell and the capillary endothelial cell itself |
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Term
| spleen has three main functions: Name them. |
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Definition
1) Production of immunological responses against blood-borne antigens.
2)Removal of particulate matter and aged or defective blood cells, particularly erythrocytes, from the circulation.
3) Haemopoiesis in the normal fetus and in adults with certain diseases. |
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Term
| What are the predominant cell type at 5 days? |
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Definition
Macrophages are the predominant cell type in damaged tissue at 5 days.
Inflammatory cell activation, Migration and function
Macrophages and other mononuclear leukocytes enter the wound after 24hours and are the predominant cell type in damaged tissue at 5 days(Figure 14-1). Macrophage infiltration into the wound site is mediated by various chemotactic factors that are released by platelets in the fibrin clot, keratinocytes at the wound margins,fibroblasts, and leukocytes. These cells also are activated through receptor-mediated processes that result in cellular and humoral responses and in phagocytosis of damaged tissue components and foreign material. They also release many potent growth factors (transforming growth factor β[TGF-β], platelet-derived growth factor, interleukin-1, and others),cytokines, and chemokines. These soluble mediators are critical for the next phase of wound repair involving cell recruitment and differentiation and the commencement of rebuilding damaged tissues. Macrophages are a major source of cytokines involved in lymphocyte chemotaxis and later constitute the most prominent leukocyte subset in wounds. TGF-β in particular stimulates fibroblasts to proliferate and synthesize extracellular matrix proteins. In the absence of
macrophages, fewer fibroblasts are stimulated during healing, so thathealing is slowed and less repair tissue is produced. |
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Term
| How do neutrophils and macrophages get to the damaged area from the blood vessels? |
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Definition
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Term
| How does gene transfer occur? |
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Definition
| Through viral vectors like adenoviruses and adeno-associated viruses |
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Term
| How does the oocyte change in size in the transition from primordial germ cell to secondary oocyte? |
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Definition
| Once within the ovary, the ooctyes halt in the meiotic prophase. They also induce connective tissue cells to form a single layer around the oocyte (primordial ovarian follicle). Follicular maturation is stimulated by FSH (secreted by the anterior pituitary) as well as the oocyte itself. This causes the primordial follicle to mature into the primary follicle (granulosa cells). Its oocyte has greatly enlarged and the follicular cells have multiplied by mitosis and become cuboidal in shape. Then the surrounding stromal cells begin to form an organized layer around the follicle called the thecal layer, which is separated from the granulosa cells by a basement membrane. The primary follicle begins to enlarge and the granulosa cells continue to proliferate, forming a layer several cells thick called the zona granulosa. The zona granulosa continues to proliferate and within it small fluid filled spaces appear, which fuse to form the follicular antrum in which follicular fluid accumulates. At this stage the oocyte has almost reached its full size and becomes situated eccentrically in the thickened area of the granulosa called the cumulus oophorus. At the periphery of the follicle, the thecal layer has developed two layers, the theca interna and the theca externa. Approaching maturity, the oocyte stops growing and the first meiotic division is completed at ovulation. At this stage, the oocyte becomes known as the secondary oocyte and commences the second meiotic division but does not complete it. Second meiotic division is not completed until fertilization. |
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Term
| What is the physiological role of the corpus luteum? When is it present? |
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Definition
| Corpus luteum is the ruptured follicle and has a brief function as an endocrine gland. In response to LH, the granulosa cells begin to secrete progesterone. Progesterone promotes changes in the endometrium that make it ready for implantation of the embryo. The cells of the thecal layer also increase in size and continue to secrete estrogen, which is necessary to maintain the thickened uterine mucosa. Increased progesterone decreases secretion of LH. Without LH, the corpus luteum regresses to form the functionless corpus albicans. The corpus luteum is also present during pregnancy for a short while. The fetus secreted HCG, which like LH, maintains the function of the corpus luteum secreting esterogen and progesterone until about the ninth week of pregnancy. After that corpus luteum regresses to form the corpus albicans and the placenta takes over secreting hormones. |
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Term
| What are the names of the layers of the uterus, and what changes occur during the follicular phase of the menstrual cycle? |
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Definition
A. endometrium: mucosal lining
1. proliferative phase: endometrium cells proliferate, becoming thicker and richly vascularized. Simple tubular glands elongate to form numerous long coiled glands that begin secretion at the same time as ovulation.
2. secretory phase: release of progesterone from the corpus luteum after ovulation promotes production of a copious thick glycogen-rich secretion by the endometrial glands; lamina propria becomes edematous
B. myometrium: thick smooth muscle wall
1. proliferative phase: branches of the uterine artery pass thru the myometrium and branch into either straight arteries or spiral arteries. |
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Term
| How does the epithelium of the endocervix differ from that of the ectocervix? From what cell type do cervical cancers usually develop? Where are these cells located? |
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Definition
A. Endocervix: single layer of tall columnar mucus secreting epithelial cells
B. Ectocervix: thick stratified squamous epithelium (same as vagina)
- usually have a clear cytoplasm due to high glycogen content
C. Cerivical cancer: most cervical cancers are squamous cell carcinomas from the ectocervix. |
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Term
| Describe in detail the consequences of high and low blood calcium, to parathyroid hormone and calcitonin production and to bone metabolism. |
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Definition
| Low calcium levels stimulate the secretion of PTH, which increases the rate of osteoclastic activity and promotes the breakdown of the bone matrix. Increased serum levels of calcium stimulate the secretion of calcitonin which increases the rate of osteoblastic activity and decreases osteoclastic resorption. |
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Term
| List the biochemical steps involved in the synthesis, iodination and hydrolysis of the thyroglobulin to form thyroxine, and relate each step to the ultrastructural organization of the follicle cell. |
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Definition
-Follicular cells concentrate iodide from the blood by means of an iodide pump in the basal plasma membrane.
- Within the cell, iodide is oxidized to iodine and transported to the follicular plasma membrane where it is released into the follicular lumen.
- The glycoprotein thyroglobulin is synthesized in the rough endoplasmic reticulum, glycosylated and packaged by the Golgi apparatus, then released into the follicular lumen by exocytosis.
- In the follicular lumen (not in the follicular cells), iodine combines with tyrosine residues of the thyroglobulin to form the inactive forms of the thyroid hormones. (= colloid)
- When active hormone is required, the follicular cells remove some of the stored colloid by pinocytosis. These vesicles are joined with lysosomes, which digest the inactive form to form the hormones tri-iodothyronine (T3) and tetraiodothyronine (thyroxine, T4). |
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Term
| At the electron microscope level, describe the process of secretion and storage of thyroglobulin. |
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Definition
| The glycoprotein thyroglobulin is synthesized in the rough endoplasmic reticulum, glycosylated and packaged by the Golgi apparatus, then released into the follicular lumen by exocytosis. |
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Term
| Parafollicular cell(aka C-cells) |
|
Definition
secretes calcitonin
1. derived from the ultimobrachial element of the fourth brachial pouch
2. ultrastructure: centrally located nucleus (non-polarized), secretory granules found all over the cell, Golgi, rER |
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Term
|
Definition
: secretes thyroglobulin (thyroid hormone precursor)
1. develops from epithelial down growth from the fetal tongue
2. composed of cuboidal epithelial cells bound by a basement membrane
3. ultrastructure: microvilli at lumen, basally located nucleus, Golgi, lots of rER
-iodide pump as basal membrane which concentrates iodide from the blood |
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Term
| Describe the histology and ultrastructure of the major cell types of the parathyroid gland. |
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Definition
A. Chief or principal cell:
1. small, round central nuclei with pale eosinophilic or clear cytoplasm
2. synthesize and secrete PTH = lots of rER
B. Oxyphil cell:
1. tend to occur in nodules, have lots of eosinophilic cytoplasm packed with mitochondria
2. do not secrete PTH and increase in number with age |
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Term
| anterior pituitary contain what cells? |
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Definition
- acidophils: growth hormone (GH) or somatotropin (STH), prolactin
- basophils: thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), lutenizing hormone (LH), adrenocorticotrophic (ACTH), and melanocyte-stimulating hormone (MSH) |
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Term
| Describe the embryological origin of the cells of the adrenal medulla. State precisely the way in which they are innervated. Name the hormones that they secrete. |
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Definition
*The secretory cells of the medulla are called chromaffin cells. Embryologically, the medulla has a similar origin to that of the sympathetic nervous system (neural crest) and is considered a highly specialized adjunct of this system.
The medulla secretes the catecholamines norepinephrine and epinephrine. Secretion is controlled by preganglionic neurons of the sympathetic nervous system. In fact, the medulla can be considered functionally equivalent to the postganglionic neurons of the sympathetic nervous system. |
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Term
| Glucocorticoids: cortisol: zona fasciculata |
|
Definition
1. raise blood glucose levels and increase cellular synthesis of glycogen; also increase the rate of protein breakdown and rate of liberation of lipids from issue stores
2. secretion is controlled by the hypothalamus via ACTH. This means that many stimuli, such as stress, can promote glucocorticoid secretion. |
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|
Term
| Mineralocorticoid: aldosterone- zona glomerulosa |
|
Definition
1. acts directly on the renal tubules to increase sodium and therefore water retention; this increases ECF volume and increases arterial blood pressure
2. secretion is controlled by renin-angiotensin system, which is controlled by the macula densa of the distal renal tubule; secretion is independent of ACTH control |
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Term
| What type of junction is the blood-retinal barrier? and where is this located? |
|
Definition
| Tight junction and is b/t choroid layer and the retinal pigmented epithelial |
|
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Term
|
Definition
Glaucoma is the blockage of either the canal of Schlem or Trabecular Meshwork. Note that Aqueous humor is either produced in the cilary processes or the trabecular meshwork.
Cataracts is when there is a issue with the lens that causes it to be opaque; this can be from UV crosslinking of the crystaline cell from within the lens. |
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Term
| Describe the path of a sound wave from the external auditory meatus to the round window. |
|
Definition
External Auditory meatus (air vibration) to tympanic membrane (solid vibration) to malleus (solid vibration) to incus (vibration of solid) to stapes (vibration of solid) to membrane on oval window to fluid waves within the cochlea to membranes of the cochlear duct (tectorial membrane and basilar membrane)
sound is transduced when oscillatory movements of the basilar membrane cause transient changes in the transmembrane voltage of the hair cells and, consequently, the generation of action potentials in cochlear afferent nerve fibers. The activity of a large number of cochlear afferent fibers can be recorded extracellularly as a compound action potential. |
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Term
| Name the parts of the membranous labyrinth and describe the locations and functions of the special sensory areas within it. |
|
Definition
The membranous labyrinth is filled with endolymph and possesses the following specialized areas: the saccule and utricle, the semicircular ducts, and the cochlear duct.
Membranous labyrinth
a. Within chambers of osseus (bony) labyrinth
b. Comprised of the semicircular ducts, cochlear duct (scala media), saccule
and utricle
c. Contains endolymph
1) Ionic composition akin to intracellular fluid (high K+, Low Na+)
2) High in potassium ions, low in sodium ions
3) In communication via duct with endolymphatic sac in subdural space
4) Endolymph formed in stria vascularis and other sites (ion transport)
5) Endolymph absorbed in the endolymphatic sac
Sensory systems in inner ear
a. Vestibular system – senses position and motion of head
1). Utricle and saccule – sense gravity and linear acceleration
2). Semicircular canals – sense head rotation (angular acceleration)
b. Cochlea – senses sound |
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Term
| Describe, compare and contrast the structure and function of the organ of Corti, the crista ampullaris and the macula. |
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Definition
The organ of Corti sits on the basilar membrane, which connects
the osseous spiral lamina with the spiral ligament. The organ of Corti, the specialized receptor organ for hearing, lies on the basilar membrane and is composed of neuroepithelial hair cells and several types of supporting cells.
Inner hair cells for sound transduction
Outer hair cells modulate sensitivity to sound.
The crista ampullares senses angular rotation of the head. Sloshing of the endolymph causes the stereocilia buried in the cupula to bend
The maculae are located in the saccule and utricle, both located in the vestibule of the inner ear.
The macula of the inner ear senses linear acceleration of the head. Inertia of the otoliths causes the otolithic membrane to lag behind, bending the stereocilia |
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Term
| Name the various hair cells found in the inner ear, indicate where each is found, and describe the structure and function of each (you do not have to know the distinction between type I and type II hair cells – only where they are found). Describe the structure of a sterocilium and of a kinocilium. |
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Definition
Each semicircular duct has a small dilation, the ampulla, where it joins the utricle.
Within the each ampulla is a sensory area, the crista ampullaris. Cells include
a. Hair cells (type I and type II) with stereocilia; unlike in cochlea, each also has one kinocilium. Recall that stereocilia are like microvilli in structure, only longer. Kinocilium, in contrast, is a cilium, with an axoneme (KEY POINT).
When the head rotates, the endolymph sloshes, bending the stereocilia and the
kinocilium.
Hair cells (inner and outer) of cochlea
a. Have stereocilia, but unlike hair cells in vestibular organs, no kinocilium
Stereocilia are not related to cilia – rather, they are long microvilli
b. Stereocilia linked by “tip links”
c. Sound causes stereocilia to bend, stretching tip links, which mechanically open channels in stereocilia
d. Once channels open, potassium ions enter hair cells, causing depolarization & release of transmitter onto spiral ganglion afferents
. Each macula has type I and type II hair cells and supporting cells
D. The hair cells each have a number of stereocilia and one kinocilium
E. Stereocilia and kinocilia are embedded in the otolithic membrane
F. The otolithic membrane has otoliths (literally, “ear stone”) made of calcium carbonate
G. When the head accelerates linearly, the otolithic membrane lags behind, bending the cilia and changing the activity of the vestibular nerve. |
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Term
| Describe the locations of endolymph and of perilymph, and indicate which meningeal space the perilymph is in contact with. Recognize where endolymph is formed and where it is absorbed. Describe the difference in ionic composition between the endolymph and the perilymph. |
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Definition
The membranous labyrinth is filled with endolymph
High K+, low Na+
The bony labyrinth is filled with perilymph
High Na+, low K+.
Perilymph is an extracellular fluid located within the cochlea (part of the ear) in 2 of its 3 compartments; the scala tympani and scala vestibuli. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid. The perimembranous space is directly connected with the subarachnoid space and, like the latter, is crossed by delicate fibrous strands and lined by squamous epithelium; the perilymphatic fluid is thus similar in composition to CSF. The major cation of perilymph is sodium. Endolymph is the fluid contained in the membranous labyrinth of the inner ear. The endolymph is formed within the cochlea and circulates throughout the inner ear. An extension of the inner ear, known as the endolymphatic duct and sac, lies against the dura or covering of the brain. Within the endolymphatic sac, endolymph is filtered through to the connective tissue around the sac. From here, the fluid can enter blood vessels or enter the spinal fluid space. |
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Term
| Describe the location, function and mechanism of action of tip links. |
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Definition
The fast response to deflection of the cilia is based on direct opening of ion channels by “tip links” that connect the tip of each stereocilium with the shaft of the next taller one. With deflection, the tip links are subjected to a lever action that transiently opens the channels, permits the entry of K+ (because of the high [K+] and high potential in endolymph), and depolarizes the hair cell. Ankle links and tip links connect the cilia – they will move with the stereocilia and lead to opening of ion channels.
Mutations can derive to pathological conditions of deafness. |
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Term
| Describe the difference in function between the inner and outer hair cells. Indicate which contracts in response to sound, and tell what this accomplishes. |
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Definition
Organ of Corti hair cells:
Inner hair cells transduce sound.
• When depolarized in response to sound, the inner hair cell releases neurotransmitter onto nerve endings of sensory nerves located in the spiral ganglion (see Wheater Figs. 21.24 b and 21.26 for a micrographs showing the spiral ganglion).
• The neurotransmitter of the inner hair cell is glutamate. Overexposure to loud sounds can damage the peripheral processes of the spiral ganglion cells.
Outer hair cells modulate sensitivity to sound.
• The outer hair cells shorten and lenthen in response to sound. Outer hair cell movement is believed to AMPLIFY sound in the vicinity of the associated inner hair cells |
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Term
| Name and describe the disease which results from increase in volume of endolymph. |
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Definition
Ménière’s Disease
• Increase in volume of endolymph
• Cause unknown
• Typically involves one ear only
• Symptoms include episodic attacks of
– Vertigo
– Nausea & vomiting
– Nystagmus
– Tinnitus |
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Term
| Describe the role of gap junctions within the inner ear. Explain what happens if these gap junctions are not functional (for instance if connexin 26 is mutated). |
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Definition
Potassium Recycling and Gap Junctions:
Potassium entering hair cells leaves the cells again on their basolateral side (going down its concentration gradient), and is recycled back to the stria vascularis via gap junctions.
Mutations in some connexins (e.g. cxn 26) can cause deafness |
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Term
| Recognize other mutations mentioned in the lecture which can lead to deafness. |
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Definition
| Usher’s syndrome= When there is a mutation in the myosin in the sterocilia of a hair cell (note that Microtub’s never exist there even in a non-disease state). The other cause of deafness is when you block connexin of gap junctions that recycle the potassium from the basil memebrane back at the Stria Vascularis epithelium (Where GAP junc’s exist). |
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Term
| Describe the structure and function of the choroid and sclera. Explain where the pathology occurs in age-related macular degeneration. |
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Definition
A. Choroid: lies between the sclera and retina
1. layer of loose connective tissue
2. provides support for the retina: richly vascularized, nutritional
3. highly pigmented: melanized-melaoncytes, brown, absorbs stray light
B. Sclera: opaque
1. thick layer of dense irregular tissue (DICT) type 1 collagen
2. protects and maintains shape
3. fibrous coat, supportive function, inelastic- provides insertion for extraocular muscles
AGE-RELATED MACULAR DEGENERATION is due to the destruction of the cones in the FOVEA |
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Term
| Describe the structure and functions of the pigment epithelium and how it is affected by a detached retina. |
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Definition
-The retinal pigment epithelium absorbs light due to its pigment granules. It prevents the back reflection of light striking the retina. It contains tight junctions that make it a part of the blood-retinal barrier. It sustains metabolism or pigment turnover of photoreceptors. In addition to phagocytosis, the pigmented epithelial cells provide structural and metabolic support for rods and cones.
-The photoreceptor cells are normally closely attached to the retinal pigment epithelium so that the pigment epithelium can maintain a vital support function. This junction can be the site of separation of the retinal layers (retinal detachment) which can lead to loss of vision in the detached area. |
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Term
| Describe and compare the structure and function of the rod and cone outer segments. Recognize how they differ and how their structure relates to function. |
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Definition
A. Rods:
1. long slender bipolar cells
2. rhodopsin: low light intensity
3. continuously sheds membranous discs which are phagocytized by pigmented epithelium
B. Cones:
1. similar in basic structure with rods except discs are more flattened, don’t shed discs
2. contain visual pigments receptive to blue, red, green light
3. higher light intensity; color, detail |
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Term
| Identify the four layers of cells (nuclei) present in the retina and name the cell types present in each layer. Describe the fovea centralis and optic disc (papilla). |
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Definition
A. Layers of the retina
1. Pigment epithelium:
2. Outer nuclear layer: cells bodies of the cones and rod photoreceptors
3. Inner nuclear layer: cell bodies of the integrating neurons of BIPOLAR CELLS
4. Ganglion cell layer: sell bodies of the optic tract neurons (retinal ganglion cells)
B. Fovea (centralis):
1. conical depression in the retina corresponding to the point where the visual axis of the cornea and lens meet the retina
2. pure cone photoreceptor region = area of greatest visual acuity
C. Optic disc (papilla):
1. is the area where the axons of the ganglion cells exit the eyeball
2. has no photoreceptors = blindspot |
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Term
| Describe the structure and function of the ciliary processes and ciliary muscle. Describe the structural-functional relations involved in accommodation of the eye. |
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Definition
A. ciliary processes
1. branching epithelial folds
2. secrete aqueous humour
B. ciliary muscle
1. smooth muscle
2. when it contracts, tension on the suspensory ligament is reduced, thus permitting the lens to assume a more convex shape.
- permits fine focusing of images already roughly focused on the retina by the cornea |
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Term
| Describe the structure and function of the iris. Explain what is unusual about the dilator pupillae. Identify the factors that determine eye color. |
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Definition
| *The iris is a continuation of the ciliary body (which is a continuation of the choroid). It extends in front of the lens, separates the anterior and posterior chambers. It acts as an adjustable diaphragm which regulates the amount of light reaching the retina. The main mass consists of loose highly vascular tissue which is pigmented due to the presence of numerous melanocytes scattered in the stroma. The dilator pupillae myoepithelial cells are innervated by the sympathetic nervous system. The color of the iris depends on the amount of pigment in the stroma. Blue eyes contain little pigment whereas brown eyes have a lot. |
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Term
| Describe the structure of the cornea. Discuss the features that are believed to be responsible for its transparency. Explain the high success rate of corneal transplants. |
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Definition
A. Structure
1. avascular
2. consists of 5 layers
a. outer surface lined by stratified nonkeratinized squamous epithelium (6 cells thick)
b. Bowman’s membrane
c. substantia propria/stroma: DRCT (REGULAR!!)
d. Keratocytes: fibroblasts with elongated nuclei and barely visible cytoplasm (Descenmet's memebrane?)
e. inner surface: lined with flattened ENDOthelial cells
3. limbus: corneo-scleral junction; marked internally and externally by a shallow depression
B. The very regular, close packing of the collagen fibrils in the corneal stroma is believed to be responsible (at least in part) for its transparency |
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Term
| Describe the structure and function of the trabecular meshwork. Relate it to the Canal of Schlemm. Describe the formation, circulation, and absorption of the aqueous humor. Discuss the causes and consequences of glaucoma. |
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Definition
*Aqueous humor is secreted into the posterior chamber and flows into the anterior chamber. At the angle of the anterior chamber there is a meshwork of fine collagenous trabeculae lined by epithelium. Aqueous humor percolates thru the spaces between the trabeculae before reaching the canal of Schlemm.
*The ciliary processes are responsible for the continuous production of aqueous humor(as well as the trabecular meshwork). The production of aqueous humor is an active process mediated by the two epithelial layers lining the ciliary processes. Balanced rates of secretion and absorption result in the maintenance of a constant intraocular pressure which stabilizes the lens and cornea. It also provides for the continuous exchange of metabolites with the cells of the avascular cornea and lens. Aqueous humor is continuously reabsorbed in the canal of Sclemm at the base of the anterior chamber.
*Even if the drainage is obstructed, the ciliary processes continue to secrete, leading to a constant increase in the intraocular pressure (glaucoma). If untreated this causes damage to the neural retina and can cause blindness. |
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Term
| Describe the structure of the lens and lens fibers. Discuss the features that cause the lens to be transparent. Explain the term cataract. |
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Definition
| The lens is an elastic bioconvex structure which, although transparent and apparently amorphous, is almost entirely composed of living cells. The lens cells are highly modified epithelial cells. The lens cells in the central anteroposterior axis then undergo maturation, losing their nuclei to become known as lens fibers. The lens fibers are elongated, protein-packed, lose organelles. The proteins are called CRYSTALLINS, which are translucent (this is why the lens is transparent). If there is damage to either the lens fibers or if the crystallin proteins aggregate, then the lens becomes opaque and light is either diffused or blocked. This lens opacity is called a cataract. |
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Term
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Definition
| Embryogenesis of ovaries; The ovary is formed from the gonadal ridge of the primitive kidney, the mesonephros |
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Term
| Retinoic acid function within the Female reproduction? |
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Definition
| What Determines Whether the Germ Cells Will Become Oocytes or Spermatogonia? Mesonephric tissue produces retinoic acid. Retinoic acid induces germ cells to become oocytes and begin meiosis. In Male testes contain an enzyme that DEGRADES (retinoic acid (i think retinoic acid in males is produced by serotoli cells)Male germ cells thus become sperm. I even think its degraded by Myeoid cells in testis........... |
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Term
| Relaxin's function in female reproduction? |
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Definition
-Granulosa Lutein cells also stain positively for a peptide hormone called RELAXIN
-Relaxin is stored in secretory granules of granulosa lutein cells
-Relaxin increases enzymes within the cervix that weaken it; may cause premature birth. (I THINK, this causes contractions) |
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Term
| Cytotrophoblast/syncytiotrophoblast |
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Definition
Later Blastocyst Development
1)Syncytio-trophoblast (no cell membranes between nuclei!), Outer most layer:
*Roles for Placenta
Syncytiotrophoblast is permeable to:
Ions
Nutrients (glucose, amino acid, HDL transporters are present)
Maternal IgG
Drugs: the placenta forms a partial barrier inhibiting the access of some drugs, but not all, to the fetus
2) Syncytiotrophoblast- 2nd layer in
3)yolk/amniotic Roles for Placenta
NEED MORE INFO |
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Term
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Definition
is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast
*Placenta also synthesizes hormones like hCG, somatomammotropin, and Progesterone |
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Term
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Definition
| High in secretory IgG (plasma cell origin), secreted just after parturition (after birth of infant) |
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Term
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Definition
| part of the Milk Constituents protein; Binds iron and is bacteriostatic |
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Term
| What are the predominant cell type at 5 days? |
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Definition
| Macrophages are the predominant cell type in damaged tissue at 5 days |
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Term
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Definition
| serine proteases secreted by striated ducts |
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Term
| Antigen stimulated lymphoid nodules/follcles are termed as? |
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Definition
| secondary nodules/follicles!! |
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