IV. The Body’s Defense Against Disease

A. Non Specific Defense Mechanisms: Innate Immunity

1. The Skin and Mucus Membrane: External Defenses are Physical barriers

a)Perspiration, tears and saliva contain ______an enzyme that attacks the cell wall of bacteria

b)______destroys proteins in germs by low pH

c)______traps germs

2. Phagocytes and Natural Killers: Internal Defenses

a)______-long living cells which develop from monocytes and engulf cells which display antigens (foreign protein patterns)

b)______-short living phagocytes which usually die after engulfing a germ

c)______-identify and destroy infected body cells by lysing membranes

3. Antimicrobial Proteins: Internal Defenses

a) ______-inhibits the production of viral proteins

1)Makes cancer cells less likely to metastasize

2)Triggers inflammatory response

3)Attracts macrophages

b) ______-group of about 30 proteins which facilitate phagocytosis and lysis of infected membranes

4. Inflammatory Response

a) ______release ______which dilate and increase the permeability of blood vessels

1)Increase blood supply to infected area

2)Causes a leakage of plasma into area

b)Release of ______which stimulates the release of WBC from the bone marrow

c)Chemical signals also attract phagocytes

d)______-increase body temperature which facilitates phagocytosis and inhibits bacterial growth

B. The Immune Response

  1. Active Vs Passive Immunity

a)______-the body is stimulated to produce its own antibodies

b)______-fetus gets antibodies from mother or antibodies are injected into a patient

  1. Duality of the Immune System

a)______-the production of antibodies which circulate as soluble protein in the blood and attack free germs

b)______- produces cells which attack infected cells directly

C. The Humoral Immune Response

  1. ______or B cells are activated by antigens directly or by T lymphocytes
  1. Activated B cell begin to produce two other types of cells

a)______-survive for long periods of time and proliferate rapidly when exposed to the same antigen

b)______-begin producing as many as 2000 antibodies per second for 4 to 5 days

c)

3. One Method of B Cell Activation

4. Antibodies constitute a group of proteins called ______Ig

a) Antibody Structure

•Y shaped molecule composed of 4 polypeptide chains: 2 light (small), 2 heavy chain (larger)

•All four chains have regions that are constant and regions that are variable

•The variable regions function as ______and are specific to each antigen

b) Types of Immunoglobulins:

1)______Five Y-shaped monomers arranged in a pentameter. Appear in initial antigen exposure and trigger agglutination.

2)______: Y-shaped monomer. Most abundant. Readily crosses blood vessels. Binds to antigen and activates compliment

3)______: Dimer of 2 Y-shaped monomers. Abundant in mucus membrane, saliva & tears

4)______: Y-shaped monomer bound to B cells. Used as a receptor for T independent antigens

5)______: Y-shaped monomer on basophils and mast cells. Antigen binding stimulates release of histamines

c) How Antibodies Work:

1)______-block viral and bacterial binding sites

2)______-attach and immobilize germs forming clumps which are then engulfed by macrophages

3)______proteins which lyse cell membranes

5. Activation of B Cells by Macrophages

a)When a macrophage engulfs a germ, partially digest antigens are displayed on its membrane

b)The antigens are mounted of Major ______(MHC): a series of glycoproteins which allow the body to recognize self from non-self

c)The macrophage is now an ______or APC and it

attracts ______

d)______bind with the APC and are activated by il-1. TH cells then release il-2 which:

1) Causes TH cells to reproduce and stimulates Killer T cells

2) Activates B Cells

e) B cells attach to T cells and begin to make ______(which

produce antibodies) and ______

6. T dependent and T independent Antigens

a)______-only stimulate the production of antibodies with the help of T cell

b)______-can bind directly with Ig D appearing on the B cell and stimulate the B cell without T cells

C. Cell Mediated Responses

  1. T cells cannot be activated by free antigens in the body fluid
  1. ______on APCs attract T cell. T cells bind with the complex and trigger:

a)Activation of B cells

b)The production of more Helper T cells

c)The production of ______(T killers)

3. T Helper Cells are able to stimulate other lymphocytes by sending and receiving

______

a)When T Helpers bind to APCs, the APC releases ______

b)The cause the T Helper to release ______which causes T Helpers to divide and helps activate B Cells and Cytotoxic T cell

4. ______(T-Killers) are cells which destroy cells with antigens directly

a)Attach to cells with antigens

b)Release ______, a protein which will lyse cell membranes

c)This kills the cell the cell and prevents it from reproducing new viruses