Term
| Describe the basic structure of the kidney and the associated blood vessels. |
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Definition
1. afferent arterioles (arterioles into glomeruli).
2. glomeruli (capillaries in renal corpuscle).
3. efferent arterioles (arterioles draining glomeruli).
4. peritubular capillaries (second capillary bed after efferent arterioles that surround renal tubules). |
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Term
| Describe the different regions of the nephron (6) |
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Definition
| Golmerates, juxtaglomerular apparatus, proximal convoluted tubule, distal convoluted tubule collecting duct in cortex, Loop of henle, collecting duct in medulla |
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Term
| Describe the structural and functional relationships between the nephron tubules and their associated blood vessels |
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Definition
| Portions of the nephron that extend from the renal corpuscle to the collecting duct allow exchange between the tubule and the peritubular capillaries. The epithelial cells in different segments are structurally different. For example, the membranes have different permeabilities and contain different transporters. In addition cells in different regions have receptors for different chemical regulators. Therefore, different segments have different functions |
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Term
| Describe the basic function of each segment of the nephron (8) |
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Definition
Renal Corpuscle: Functions to form and collect a filtrate of blood plasma.
Glomerulus: A Tuft of Capillaries At The Beginning of the Nephron.
Glomerular (Bowman’s) Capsule : The First Tubular Component of A Nephron Consisting Of A Sack-like Structure.
Proximal Convoluted Tubule: Primary function is movement of most of the water and solute back into the blood.
Descending Limb of Loop of Henle: forms a concentration gradient for water reabsorption
Ascending Limb of Loop of Henle: forms a concentration gradient for water reabsorption
Distal Convoluted Tubule: Participates in regulation of electrolytes
Collecting Duct: participates in regulation of water and electrolytes |
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Term
| Distinguish between filtration, reabsorption, and secretion as they relate to urine formation |
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Definition
Reabsorption= excretion- filtration
excretion-filtration = secretion |
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Term
| Indicate how the glomerular filtration rate (GFR) is affected by changes in the glomerular capillary pressure, the plasma osmotic pressure and the hydrostatic pressure in the glomerular capsule, respectively (5) |
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Definition
Glomerular Filtration moves solutes and water from the Glomerular Capillaries into the Glomerular Capsule). (figure 25.11 ) (Remember capillary filtration?)
Glomerular Capillaries are 100 to 400 times more permeable than normal capillaries due to the presence of larger pores (fenestra).
Filtration is determined by hydrostatic and osmotic pressure gradients between the glomerular capillaries and the glomerular capsule.
Filtration Pressure =
Glomerular Hydrostatic Pressure Gradient - Osmotic Pressure Gradient
The outward hydrostatic gradient is greater than the inward osmotic pressure gradient |
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Term
| Compare the composition of the glomerular filtrate with that of blood plasma |
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Definition
| Glomerular filtrate is protein free and cell free |
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Term
| Explain how the diameters of the afferent and efferent arterioles affect the rate of glomerular filtration |
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Definition
| vasoconstriction of the afferent arteriole and decreases GFR; efferent vasoconstriction increase pressure, increasing GFR |
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Term
| Compare the GFR with the rate of urine production |
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Definition
| Increase GFR generally should increase Urine production; GFR is about 120 times greater than urine production in mL |
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Term
| Describe the reabsorption of Na+, Cl-, H2O and other ions in the proximal convoluted tubule (6) |
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Definition
1. Sodium Is Actively Reabsorbed (requires lots of ATP)
2. Chloride Is Reabsorbed Passively Due to the Electrical Gradient
3. Water Moves Back Into the Blood in Response to The Osmotic Gradient |
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Term
| Describe the general role of the loop of Henle in establishing a concentration gradient between the medullary interstitial fluid and the collecting duct that allows the kidney to concentrate the urine |
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Definition
Concentration highest at end of collection duct.
Loop of henle = separate by active transport of sodium. Asending pump NaCl out into intracellular fluid. NaCl moving out of ascending sends water out of desending filtrate. Create high concentration before asending loop. Concentration gradient favor movement of water. |
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Term
| Describe the homeostatic control mechanism for maintaining blood volume and plasma osmolarity and the role of ADH in this mechanism |
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Definition
| Increase in osmolarity, increase in Na concretion in plasma→ osmoreceptors in hypothalamus→ posterior pituitary(stimulate of plama volume) →release ADH→act on collecting duct, increae aquaporins→ increase water reabsorption→decrease osmolarity, increase plasma volume |
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Term
| Use a causal diagram to show the mechanism by which eating a large bag of chips without drinking water would affect sodium and water reabsorption by the kidney? Include changes in both angiotensin II and ADH. Include the controlled variables, sensors, integrating centers and the specific regions of the kidney that act as effectors (pretty much guaranteed to be on the test) |
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Definition
| The increase sodium in the blood plasma would increase the osmolarity. The increased osmolarity would be detected by osmoreceptors in the hypothalamus. The hypothalamus (integrating center) would increase ADH secretion from the posterior pituitary. The ADH would increase water channels in the collecting duct (effector) and increase water reabsorption into the blood. The increase in water reabsorption along with increased water consumption would return plasma osmolarity to normal, but the blood volume and blood pressure would be increased. The increase in blood pressure would lead to a decrease in Renin (by the juxtaglomerular cells), and decrease Angiotensin II and Aldosterone secretion. The decrease in Aldosterone would reduce sodium reabsorption for the distal convoluted tubule and collecting duct. There would also be a reduction in water reabsorption from the collecting ducts due to the osmotic effect of unabsorbed sodium. The later reflex would result in excretion of the excess sodium consumed and the water that was retained initially to dilute the sodium. Both blood pressure and osmolarity would return to normal. We actually talked about this one in class. |
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Term
| Describe the distribution of water and electrolytes in intracellular fluid and intercellular fluid (6) |
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Definition
Intracellular Fluid
Na+ = ~15mEq/L
K+ = ~150mEq/L
Free Ca++ = ~0.0002mEq/L
Interstitial Fluid
Na+ = 140mEq/L
K+ = ~4mEq/L
Ca++ = ~2mEq/L |
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Term
| Describe how plasma osmolarity (plasma Na+)is regulated by the kidney |
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Definition
Sodium excretion is affected by changes in plasma osmolarity and blood pressure. There are effectively no sensors for plasma Na+
Renal Na+ Excretion = Na+ Filtered - Na+ Reabsorbed |
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Term
| Describe the role of the renin-angiotensin system in the regulation of Na+reabsorption |
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Definition
| Reabsorption Of Na+ Form The Distal Convoluted Tubule And Collecting Duct Is Regulated By Aldosterone |
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Term
| Describe the function of the juxtaglomerular apparatus in the regulation of Na+ reabsorption |
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Definition
The juxtaglomerular apparatus is involved in local autoregulation of GFR and also regulates the release of the hormone Renin in response to changes in GFR The GFR also increases and there is a subsequent decrease in Renin/angiotensinII/aldosterone that, in turn, decreases Na+ reabsorption (and increases Na+ and water excretion)
Structure formed by the association of juxtaglomerular cells in the afferent arteriole and specialized cells in the distal convoluted tubule called the macula densa. The juxtaglomerular apparatus is involved in local autoregulation of GFR and also regulates the release of the hormone Renin in response to changes in GFR |
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Term
| Describe how plasma K+ is regulated by the kidney (5) |
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Definition
K+ Excreted = (K+ Filtered + K+ Secreted)- K+ Reabsorbed
Most K+ Is Reabsorbed In The Proximal Tubule And Ascending Loop.
K+ Can Be Either Secreted Or Reabsorbed By Cortical Collecting Ducts.
Collecting Duct K+ Transport Is Regulated By Aldosterone (increased aldosterone increases K+ secretion).
The sensor and integrating center for regulation of plasma K+ is the adrenal cortex and Aldosterone secretion increases as plasma K+ increases. |
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Term
| Describe the age-related stages of reproductive function |
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Definition
Fetal And Infancy: Reproductive Hormones Secreted
Infancy To Puberty: Hormone Secretion Is Decreased
Puberty -Adulthood: Hormone Secretion Is Increased
Old-Age: Gonadal Responsiveness to Gonadotropins Decreases |
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Term
| Explain the function of the ~germ cells, sustentacular cells, and interstitial cells in the testis (7) |
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Definition
Sustentacular (sertoli) Cells: \ Support Cells (Regulated by Testosterone and FSH)
A. Blood Testis Barrier
B. Nourish Developing Sperm
C. Produce Androgen Binding Protein
D. Secrete Paracrine Agents That Stimulate Sperm Production And Maturation
E. Secrete Inhibin Which Inhibits FSH Secretion
Interstitial Cells Which Secrete Androgens |
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Term
| Describe the structure of a sperm |
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Definition
Head
Acrosome (Digestive Enzymes)
Nucleus (With 23 Chromosomes)
Body
Contains Mitochondria
Tail (Flagellum)
Propels the Sperm |
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Term
| Explain the roles of GnRH, LH (ICSH) and FSH in the control of male reproductive functions (4) |
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Definition
Hypothalamic GnRH Stimulates Release of LH (ICSH) And FSH From The Pituitary
ICSH Promotes Development of Interstitial Cells Which Secrete Androgens
FSH: Stimulates Growth of Sustentacular Cells And Causes Them To Become Responsive To Testosterone
Inhibin Is Secreted By Sustentacular Cells; Functions to Inhibit Pituitary FSH Secretion |
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Term
| Describe the actions of testosterone and inhibin (7) |
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Definition
1. Developmentally Promotes The Formation Of Male Reproductive Organs; Promotes Descent Of The Testes Into The Scrotum
2.At Puberty Promotes Development Of Testes And Accessory Structures
3 Promotes Secondary Sexual Characteristics
4. Promotes Spermatogenesis
5. Protein Anabolism/ Bone Growth
6. Maintains Sex Drive
Inhibin→ inhibit FSH secretion→ no sustentacular cells that resond to testosterone |
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Term
| Describe the structure of the ovary (5) |
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Definition
Medulla: Inner Region Composed Of Connective Tissue, Vessels And Nerves
Cortex: Contains The Ovarian Follicles
Follicles: Epithelial Cells (Follicular Cells) Surrounding An Oocyte
All Oocytes Are Formed Early During Development.
Oocytes: Are In An Arrested Stage Of Division Prior To Puberty |
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Term
| List the major steps in oogenesis and compare and contrast oogenesis and spermatogenesis |
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Definition
Oogenesis: Beginning At Puberty Primary Oocytes Are Stimulated To Continue Meiosis (A Few Each Month). The Second Meiotic Division Is Only Completed In Fertilized Eggs) (figure 28.15)
Spermatogenesis and Spermiogenesis) (figure 27.7-8)
Begins At Puberty And Continues Throughout Life |
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Term
| Describe maturation of a follicle and the process of ovulation (8) |
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Definition
Stimulated By FSH
Several Follicles Begin Maturation but Generally Only One Matures
1. Oocyte Enlarges
2. Follicular Cells Proliferate
3. A Fluid Filled Cavity Is Formed That Produces A Secondary Follicle
4. Ovarian Cells Form Two Layers Around The Follicle
A. Theca Cells
Secrete Androgens Locally
B. Granulosa Cells
Nourish Oocyte
Secrete Estrogen And Inhibin |
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Term
| Explain the role of GnRH, LH and FSH in regulating female reproductive functions (9) |
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Definition
FSH follicle stimulating hormone
Stimulates Follicle Growth
LH
1. Stimulates theca cells
2. LH surge simulates ovulation.
primary oocyte completes 1st meiotic division
follicle blood flow and antrum size increase
lytic enzymes and prostaglandins break down follicular-ovarian membranes
corpus luteum develops from theca and granulosa cells
3. LH stimulates development and maintenance of the corpus luteum |
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Term
| Describe the functions of estrogen, progesterone and inhibin |
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Definition
Estrogen (From Follicles And Corpus Luteum)
1. Female Secondary Sexual Characteristics
2. Follicle Sensitivity To FSH
3. Positive Feedback Effects On Hypothalamus And Pituitary To Stimulate LH Surge
4.Endometrial Growth (Proliferative Phase)
5.Growth Of Internal And External Reproductive Structures
6.Breast Growth
Progesterone (From Corpus Luteum)
1.Secretion By The Endometrium (Secretory Phase)
2. Induces Thick Cervical Mucus
3.Contractions Of Uterine Tubes And Myometrium
4.Breast Growth
5. In Combination With Estrogen it inhibits Secretion of GnRH By The Hypothalamus
Feedback Effects Of Hormones
Low Levels Estrogen
Negative Feedback On LH And FSH
Inhibin---Inhibits FSH
High Levels Estrogen
Positive Feedback On LH And FSH
High Levels Progesterone + Estrogen (corpus iullum)
Negative Feedback On LH And FSH |
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Term
| Describe the ovarian cycle and how the phases are related to hormone levels (3) |
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Definition
Ovarian Events
1. Follicular Phase: Follicle Develops and Secretes Estrogen
2. Ovulation: stimulated by LH.
The Follicle Ruptures Releasing The Oocyte
The Oocyte Is Drawn Into The Uterine Tube
3. Luteal Phase: Empty Follicle Develops Into Corpus Luteum and Secretes Both Estrogen And Progesterone |
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Term
| Summarize the major phases of the uterine cycle and relate the phases to the effects of hormones (3) |
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Definition
1. Proliferative Phase: Growth Of Endometrium
2. Secretory Phase: Further Development Of Endometrium In Preparation For Implantation (Mucus Glands Develop) nessecary for implation to occur
3. Menstrual Phase: Necrosis And Sloughing Of Endometrial Lining |
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Term
| What are the functions of the kidney? (6) |
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Definition
Primary Function: regulation of the extracellular fluid (plasma and tissue fluid) environment of the body.
1. Elimination of metabolic wastes (e.g. urea, uric acid and creatinine) and excretion in the urine.
2. Removal of foreign chemicals from the blood and excretion in the urine.
3. Regulation of plasma water and concentrations of H+, Na+ K+ Ca+2 , HCO3- and other ions
4. Control of blood pressure (by helping to maintain blood volume)
5. Secretion of hormones (e.g erythropoietin and renin). |
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Term
| Describe The Processing of Blood Plasma and Formation of Urine (4) |
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Definition
1.Glomerular Filtration: bulk flow of an essentially protein free plasma from glomerular capillaries into the glomerular capsule.
2.Tubular Reabsorption: Transfer of Substances From The Renal Tubules Into The Peritubular Capillaries.
3.Tubular Secretion: Transfer of Substances From The Peritubular Capillaries Into The Renal Tubules.
4. Excretion: Urine leaves the collecting ducts and empties into minor calyces that drain into major calyces that drain into the renal pelvis and through the ureters to be stored in the urinary bladder until urination |
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Term
| Where do reabsorption and secretion occur? What percentage of water that is filtered is returned to the blood? |
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Definition
Reabsorption and Secretion occur in all segments of the renal tubule after the glomerular capsule.
Reasorption is the most important process in the Proximal Tubule (~65% of The salt and H2O That Was Filtered Is Always Returned To The Blood) (figure 25.13-14) |
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Term
| how can the concentration of the urine be varied when H2O is always transported passively by osmosis? |
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Definition
a concentration gradient must be created to favor movement of H2O
Dependent on variable permeability of tubular segments and to H2O and the loop of Henle. |
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Term
| Water Permeability Of Renal Tubular Segments (5) |
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Definition
Proximal Convoluted Tubule: Very Permeable
Descending Loop Of Henle: Permeable
Ascending Loop Of Henle: Not Permeable
Distal Convoluted Tubule: Not very permeable
Collecting Duct: Permeability is regulated |
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Term
| Describe the countercurrent multiplier system of the loop of Henle, and the overall result |
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Definition
Exchange between the ascending and descending limbs of the loop of henle.
Increases the osmolarity of the extracellular fluid in the medulla of the kidney.
Concentrated extracellular fluid in the medulla provides a gradient for water absorption when the collecting duct is made permeable to water by ADH
The interstitial fluid becomes more concentrated within the medulla
The fluid in the renal tubule becomes more dilute.
The system allows excretion of either urine ~1/3 the concentration of blood plasma or up to ~4x more concentrated than blood plasma. Urine concentration also depends on the permeability of the collecting duct, and is, therefore, dependent on ADH |
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Term
| What two factors can affect sodium excretion? |
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Definition
1. Changed by changes in GFR: increasing GFR tends to passively increase sodium excretion and decreasing GFR tend to decrease sodium excretion (unless there are regulated changes in reabsorption)
2. Changes in Na+ Reabsorption |
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Term
| What factors affect GFR? (3) |
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Definition
GFR Is Changed By Vasoconstriction or Vasodilation of Afferent and Efferent Arterioles
1. Local autoregulation keeps the GFR fairly constant with small changes in blood pressure
2. Sympathetic Nervous System promotes vasoconstriction of the afferent arteriole and decreases GFR when blood pressure decreases significantly |
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Term
| What is Atrial Natriuretic Peptide? |
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Definition
| hormone secreted in response to high blood volume and pressure. The hormone stimulates a decrease in Na+ Reabsorption |
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Term
| What is the formula for bicarbonate excretion? |
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Definition
| HCO3- excretion = (HCO3- filtered + HCO3- secreted) - HCO3- reabsorbed |
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Term
| Describe the body's response to acidosis and alkalosis (4) |
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Definition
Acidosis
1. All of the HCO3- is reabsorbed via H+ ion secretion.
2. Excess H+ ions are secreted to add HCO3- to blood.
3. Tubular HCO3- synthesis is increased to add HCO3- to blood
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Alkalosis
H+ secretion is inadequate to reabsorb all of the HCO3- and HCO3- is excreted |
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Term
| What are the causes of alkalosis and acidosis? (4) |
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Definition
1. Respiratory:
acidosis: impaired CO2 removal;
alkalosis: excess CO2 removal.
2. Metabolic:
acidosis: excess production of metabolic acids; loss of HCO3- from GI tract.
alkalosis: loss of H+ by vomiting |
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Term
| Describe the homeostatic control for GnRH in males (3) |
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Definition
| GnRH leads to ICSH and FSH, ICSH leads to--Interstitial cells secrete testosterone in blood and locally. Inhibits FSH and GnRH (negative feedback) |
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Term
| What three substances are secondary active transport and their reabsorption is subject to the number of transporters |
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Definition
These are totally reabsorbed as long as plasma levels are within a normal range but will be lost in the urine when the filtrate concentrations exceed the maximum rate of transport.
Glucose, Water Soluble Vitamins, Amino Acids |
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