Chapter 31 The Bodys Defense System The Germ

Chapter 31 The Body’s Defense System

The Germ Theory of Disease n. Infectious disease is caused by pathogens that can spread the disease from one organism to another

Pathogen n. Disease causing organism n. Ex. ) bacteria, fungi, virus, protists

Transmission of Infectious Diseases n. Airborne n. Sexual contact n. Animals (ex. Lyme n. Contaminat disease) ed food or n. Physical

The human body has three lines of defense against infections

The First Line: Barriers n. Physical & chemical (non-specific defenses)

Examples: n. Skin, Hair n. Mucous membranes n. Saliva n. Stomach acid & enzymes n. Sweat, tears

The Second Line: Internal Nonspecific Defenses n 3 types: n. White blood cells n. Inflammatory response

White Blood Cells n. Travel through the body engulfing foreign invaders or destroying infected & abnormal acting cells

Macrophage

Macrophage and E. coli

White Blood Cells They are able to recognize “self” from “non-self” based on proteins on cell membranes n

These cells are from the same person so they have the same “self” proteins on their cell membranes

Inflammatory Response n. Body tries to isolate pathogen n. Proteins are released that create blood flow and

Inflammatory Response n. Causes redness, heat, swelling, pain at the location of injury

n. If Inflammatory Response pathogen enters the blood the body spikes fever to try to destroy it…

Specialized Proteins (cytokines): released by cells to help destroy invaders n Histamine – increase blood flow, can cause watery eyes and runny nose n Interferon – prevents viral reproduction in infected cells n Interleukins – call WBC

The Third Line: Targeted Defense n. The immune response is a specific response to a “non-self” protein

STARTING AN IMMUNE RESPONSE Foreign invaders - viruses, bacteria, allergens, toxins and parasites - constantly bombard our body. The response to this assault is a carefully orchestrated and controlled interaction between immune cells with the ultimate goal to eliminate the invader by pathogenspecific mechanisms.

Antigens cause a Specific Immune Response n. Antigen: n. A protein that is on the cell membrane and triggers an immune response

Macrophage ingesting yeast

Macrophage n. A large WBC that travels the body and engulfs foreign invaders (phagocytosis) n It displays the specific antigen and activates Helper T lymphocytes

Helper T Lymphocytes n. Recognize the antigen displaying WBC n. Secretes chemicals that activate both cytotoxic T cells and B lymphocytes

B Cell Lymphocytes n. Defend primarily against bacteria & viruses by creating antibodies n. Develop in Bone

Antibodies Attach to Antigens n. Antibodies - proteins found on the surface of WBCs or free in the plasma. Bind to SPECIFIC antigens to inactivate pathogens.

Cytotoxic T Cell Lymphocytes ndevelop with the ability to attack infected cells or kill the body’s abnormal cells (to prevent cancer)

Memory Cells n. Both type B & T lymphocytes produce memory cells that will activate when exposed to the same pathogen

A Summary of the Immune Response – 3 min https: //www. youtube. com/wa tch? v=Bf 2 t 8 n 1 ibw. Q

The Third Line of Defense The Immune Response

n 1. Macrophage (WBC) takes in pathogen by phagocytosis n 2. Pathogen completely engulfed n 3. Pathogen is

PATHOGEN ANTIGEN WBC

n 4. WBC “displays” the antigens; WBC releases chemicals to attract Helper T cells n 5. Helper T cells (WBCs) n 6. Helper T cells bind

WBC w/ ANTIGENS Helper T Cells Bind To Antigens HELPER T CELLS

n 7. chemicals are secreted to begin a response n 8. Helper T cells activate cytotoxic T (9) cells and memory

Helper T cells activate TC & TM cells TC cells destroy pathogen Chemical Secretion Memory T cells

n 7. chemicals are secreted to begin a response n 11. B cells are activated n 12. B cells divide n 13. Memory B cells are made n 14. Plasma B cells secrete…

B cells are activated & divide Chemical Secretion Memory B cells which make antibodies B cells develop into plasma cells Plasma

The Third Line of Defense The Immune Response

Vaccines stimulate the immune response

Vaccine development n. Edward Jenner n 1796, used cowpox to provide immunity to small pox

Vaccine development n. Louis Pasteur n 1885, developed vaccines for rabies & anthrax

Vaccine development n. Jonas Salk/Albert Sabin n 1955, Salk developed injectable vaccine for polio n 1961, Sabin developed an oral

Vaccines n. Dose of a pathogen or part of a pathogen that is disabled or destroyed no

Vaccines n. Different n. Use types: just antigens of pathogen n. Grind or heat pathogen so it can’t function n. Similar version of

Stages in Vaccine-Induced Immunity

Active Immunity n. When your body produces antibodies against an infection n. Memory Cells are Made

Active Immunity n 2 examples: n. Previous n. Vaccines infection

Passive Immunity n. When you receive antibodies from another source

Passive Immunity n. Examples: n. Fetus from mother n. Traveling antibodies temporarily protect

Disorders of the immune system are major health problems Use textbook to fill in page 6 in your notes

ABO Blood Groups n. Blood typing is determined by the antigens present on the surface of the RBCs.

Blood Groups n. This results in Four possible blood types: n. A, B, AB, O

BLOOD TYPE A

BLOOD TYPE B

BLOOD TYPE AB

BLOOD TYPE O

BLOOD TYPE RBC Antigens Present A B A&B neither A nor B Blood Type A B AB O

BLOOD TYPE Blood Type Antibodies Present in Plasma A B AB O B A None A&B

How Many Blood Types? Type A Type B Type AB Type O

BLOOD TYPE Blood Type Can Receive Type: A A O B AB A B AB O OUniversal Recipient. O

BLOOD TYPE Blood Type Can Donate To: A A A B Universal. B B AB ABDonor AB O A B AB O

Organ Transplants n. Possible rejection because body is recognizing “self” versus “non-self” tissues

Organ Transplants n. Medications suppress immune system to decrease rejection but lowers defense system against other

Plasma Donations In an emergency situation plasma may be transfused instead of blood cells. Why? ? No typing is necessary!

Blood Typing Game Turn to Page 8

Add the Rh Factor… A+ A-

Determining Blood Type:

When we add a patients blood to each test tube: If test tube A clumps, the blood contains the _______ antigen. A If test tube B clumps, the blood contains the _______ antigen. B If test tube Rh clumps, the blood contains the _______ antigen. Rh

Blood Typing Game