Term
| Functions of lymphatic system |
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Definition
i. House phagocytic cells & lymphocytes
ii. Important in body defense & disease resistance
iii. Collects excess water & proteins from intercellular fluid (in between cells)
iv. Transports fat from GI tract to the blood stream
v. Destroys microbes & foreign substances
vi. Cleanses blood of defective and old RBCs, WBCs, & platelets |
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Term
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Definition
1. Lymph vessels
2. Lymph nodes
3. Spleen
4. Thymus gland
5. Tonsils |
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Term
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Definition
1. Meandering (wondering) system of small thin-walled vessels
2. Drains excess intercellular fluid & returns it to the circulatory system |
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Term
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Definition
1. Bean shaped organs along lymph vessels, 1-25mm diameter
2. Nodes are full of cells that phagocytize foreign substances to fight infection
3. Large numbers of nodes in arm pits, neck, groin, & around the intestines
4. Contain T-cells, fixed macrophages,& B-cells
5. Unidirectional lymph flow through the nodes permits the filtration & destruction of foreign substances (like gas flow) |
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Term
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Definition
1. Fist-sized, purplish, just below diaphragm on the left side
2. Large single mass of lymphatic tissue
3. Phagocytizes dead RBCs & WBCs, microbes, toxins, & debris
4. Removes & stores iron from hemoglobin for recycling into new hemoglobin
5. Produces RBCs in fetus
6. Stores RBCs & blood platelets |
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Term
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Definition
1. Located in the thoracic cavity between the lungs
2. Consist of two lobes
3. Has two layers
a. Cortex
b. Medulla
4. Large in an infant & reaches its max size 10-12 yrs old
5. As a person ages, the gland becomes smaller |
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Term
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Definition
1. Form a ring of lymphatic tissue around the throat
2. Four sets, named based on its location
a. Palatine- on soft palate
b. Lingual- beneath tongue
c. Pharyngeal- on pharynx or throat
d. Tubal- base of auditory tube
3. Capture pathogens & phagocytize foreign substance |
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Term
| List parts of nonspecific pathogen disease resistance |
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Definition
1. skin & mucus
2. antimicrobial substance
3. natural killer cells
4. phagocytosis |
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Term
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Definition
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Term
| Mecahnical protection of skin & mucus |
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Definition
a. Epidermis
i. Physical barrier
ii. Continual shedding removes bacteria & fungi from the surface
iii. If barrier is not broken one rarely has an infection
b. Mucus membranes
i. Line body cavities
ii. Secretes mucus
iii. Lubricates surface, traps microbes, & foreign particles
iv. Ciliated cells, trap particles & sweep them toward the surface
c. Lacrimal apparatus
i. Functions to make tears
ii. Lubricate the eyes
iii. Wit the aid of the eyelids, prevents microbes from becoming established on the eye
iv. Tears also wash away particles
d. Saliva, sweat, urine, & vaginal secretions
i. All function as washing mechanisms |
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Term
| Chemical protection of skin & mucus |
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Definition
a. Sebaceous glands (oil glands)
i. Oil contains unsaturated fatty acids that retard bacterial growth
b. Perspiration
i. Flush bacteria from skin
ii. Lysozyme breaks down bacterial cell walls
iii. Lysozyme is also found in tears, saliva, & nasal secretions
c. Gastric juice
i. pH 1.2 – 3, has hydrochloric acid, destroys many bacteria |
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Term
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Definition
1. Interferons
a. Produced by body cells infected with a virus
b. Produced by lymphocytes, macrophages, and fibroblasts (cell that makes connective tissue)
c. Stimulate nearby uninfected cell to produce antiviral proteins
d. Proteins interfere with viral replication
2. Complement system
a. Composed of ~20 proteins that are normally inactive
b. Enhance certain immune, allergic & inflammatory reactions when activated
c. Some contribute to the development of inflammation (flood the tissue with fluid) |
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Term
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Definition
1. Lymphocytes that destroy intruding microbes & some tumor cells
2. Found in the spleen, lymph nodes, red bone marrow, & blood
3. Must have direct contact to kill
4. Kill by making the bacteria leaky or by damaging the cell |
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Term
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Definition
1. Phagocytic ingestion of foreign particles
2. Two kinds
a. Neutrophile
i. WBC eat bacteria & fungi
b. Macrophage
i. Develop from monocytes (agranulocyte)
ii. They are scavengers
iii. Fixed or wandering
3. Mechanism of phagocytosis
a. Chemotaxis – moving along a chemical gradient
i. Chemical attraction of the phagocyte to a particular location
ii. Chemical from the bacterial or damaged cell
b. Adherence- attaching to
i. Phagocyte attaches to the bacteria ot foreign material
c. Ingestion
i. Endocytosis
d. Digestion
i. Vesicle containing the particle or microbe if formed
ii. Lysosomes bind & pores enzymes into the vesicle
iii. Microbe or particle is oxidized
1. Hydrogen peroxide |
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Term
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Definition
1. Body’s ability to defend itself against a specific kind of invader
2. Includes a memory for most of the antigens encountered
3. Uses T-cells & B-cells that develop immunocompetence
4. During development these lymphocytes develop distinctive peripheral proteins which acts as antigen receptors
a. Antigen receptors recognize specific antigens
b. T-cells develop into CD4+ or CD8+ cells
c. Cells have proteins named CD4 or CD8 in the plasma membrane |
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Term
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Definition
a. Characteristics
i. Ability to stimulate the immune response by producing antibodies or making specific T cells
ii. Ability to react with these specifically produced antibodies or T cell
b. Antigen examples:
c. Antigens are usually large proteins
i. Peripheral proteins in a bacterial cell membrane
d. Antigenic determinant
i. The specific region of the antigen that triggers the immune response
ii. Body can recognize and bond to at least one billion different antigenic determinants
e. Major histocompatibility complex (MHC)
i. Every one MHC is unique
1. Identical twins may be an exception because of environment
ii. MHC of an individual helps the immune system recognize foreign antigens
iii. Two types of MHC antigens
1. MHC-I- molecules built into the cell membrane of all body cells except RBC’s
2. MHC- II- molecules that only appear on the surface of antigen-presenting cells
a. Cells of the thymus or T cells that have been activated by the presence of an antigen |
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Term
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Definition
a. Antigen presenting cells (APCs) process antigens
b. APCs include macrophages, B-cells, & dendritic cells
c. APCs are located in regions that are likely invasion routes, skin, respiratory, & GI tract
d. Steps
i. Ingestion of antigens by a WBC- phagocytosis
ii. Digestion of antigen into peptide fragments
iii. Production of MHC-II molecules by the cell
iv. Fusion of the vesicles containing the MHC-II molecules with the vesicles that contain the antigen peptide fragments
v. Binding of the antigen peptide fragments to MHC-II molecules
vi. Antigen peptide MHC-II complex is embedded into the plasma membrane
vii. APC migrates to lymphatic tissue & gives the antigen to a T cell
viii. T cell recognize & bind to the antigen- MHC-II complex
ix. T cell indicates an antibody or cell mediated immune response |
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Term
| Antibody-mediated immune responses |
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Definition
a. System works against antigens dissolved in body fluids
b. Antigetic bacteria that is locater between then cell-Extracellular pathogens
c. B cells transform into plasma cells
i. Plasma cells make the antibodies
ii. Plasma cells are larger than B cells
iii. They contain lots of rough ER
1. Rough ER makes proteins
iv. Found in the bone marrow & lymph nodes
v. Live 4-5 days
vi. Can produce ~ 2,000 antibodies/sec |
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Term
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Definition
a. Bind to the antigentic determinant on the antigens that trigger their production
i. Lock and Key Model
b. Are glycoproteins
c. Made of 4 polypeptide chains
i. Heavy Chains- 2 chains with ~450 AA & small carbohydrates
ii. Light chains – 2 chains with ~220 AA
iii. Each antibody has two variable regions which function as antigen binding sites
iv. The rest of the light & heavy chains are constant in their shape |
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Term
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Definition
a. To neutralize the antigen
b. Immobilize bacteria so that it can be attacked
c. Agglutination & precipitation of the antigen
i. Antibodies in blood
d. Activation of complement system
e. Enhancing phagocytosis
f. Provide fetal or newborn immunity |
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Term
| Cell-mediated immune responses |
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Definition
1. Introduction
a. Involves cells attacking cells
b. Here CD8+ T cells develop into killer T cells and directly attack the invading antigen
c. Effective against
i. Intracellular pathogens
ii. Some cancer cells
iii. Foreign tissue transplants
2. Starts with the activation of small numbers of T cells by a particular antigen
3. Activated T cells proliferate & differentiate into a group of identical cells
4. These cells recognize the same antigen & can eliminate the antigen |
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Term
| Activation of cell -mediated immune responses |
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Definition
a. First signal
i. Antigen receptors on the surface of the T cell recognize & bind to antigen fragments presented by MHC II molecules ( APCs and peptide fragments are presented )
b. Second signal
i. Molecules on the surface of the T cell & on the surface of the APC cause the cells to bind t each other temporarily
ii. Binding of these molecules is the second signal
c. Proliferation & Differentiation
i. T cell divides several times & changes into a more highly specialize cell |
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Term
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Definition
a. Helper T cells- function to stimulate the proliferation of other T & B cells that are already bound to the antigens
b. Cytotoxic T cells
i. Only T cells that directly attack & kill other cells
ii. Move around the body looking for specific antigens
c. Suppresser T cells
i. Are regulatory cells
ii. Function to suppress the activity of T cells & B cells
iii. Thought to shut off the immune response when the job is done
d. Memory T cells
i. Recognize the original invading antigen
ii. Permits faster response when the antigen is encountered in the future ( give you immunity) |
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