Unformatted text preview: Genes and the Immune System
Chapter 17 Body Defense
Three basic Levels: Level 1 Barriers Level 2 Nonspecific responses Level 3 Specific response Barrier Defense
Main barrier defense = the skin Waterproof Keeps out bacteria & viruses Mucous membranes also a barrier If whole Nonspecific Defenses Respond to any invading microbe Nonspecific Defenses involve: Complement system Inflammation Fever Complement System Produces chemicals that kill bacteria Membrane Attack Complexes (MAC) Drill holes in bacteria Cause them to explode (lysis) Also helps with inflammation Inflammation What are the symptoms of inflammation? Caused by: Mast cells (wbc's) release histamines Histamines cause fluid to move to area Activates WBC's which eat invaders The Inflammatory Response Fig. 17.3 Fever What happens in a fever? Why does your body do this? Specific Defenses Involves chemical and cellular responses Can destroy: viruses, bacteria, fungi, cancer cells Very effective Has memory fast resonse to second exposure Specific Defenses Macrophage = Antibody = Antigen = Anaphylaxis = Antibodies Fig. 17.8 Lymphocytes
B lymphocytes (B cells) mature in bone marrow (made there too) Make antibodies T lymphocytes (T cells) Mature in thymus (made in bone marrow) Assist B cells, deal with viruses Let's say bacteria invade...
1. B cells start making antibodies Antigens detected by B cells 1. 1. B cells activate T cells T cells cause B cells to divide Let's say bacteria invade
Once B cells divide they become either: Effector B cells make antibodies against invader OR Memory B cells brought out later if invader shows up again Let's say a virus invades.. Virus resides inside normal cells Harder to detect Macrophages & T cells interleukins Memory = resistance to disease on second Immune System Memory exposure Result of memory T and B cells Second response = faster and on a larger scale Vaccines What is a vaccine? Can you get disease from a vaccine? Vaccine creates memory T and B memory cells Blood Types Controlled by codominant genes: IA, IB, I Genes produce cell ID proteins on cell membrane Antibodies produced against foreign blood types Two blood groups: ABO system and the Rh blood group Rh blood type Rh rhesus factor Can be + or Gene for Rh+ is dominant Hemolytic Disease of the Newborn Rh females & Rh+ males fetus is Rh+ Mom makes antibodies against fetus Second pregnancy mom's immune system attacks fetus Prevented by immunoglobin shots Organ Transplants Must match cell surface antigens of donor and recipient Major Histocapatibility Complex (MHC) genes that make cell surface ID antigens Millions of combinations are possible Unrelated donors have a 1/100,000 1/200,000 chance of matching Genetic Engineering: Animal Human Organ Transplants Xenotransplantation = 18,000 transplants/year 100,000 die before receiving transplant 50,000 on waiting list Disorders of Immune System Allergies Autoimmune response Genetic disorders of the immune response Severe combined immunodeficiency (SCID) Severe Combined Immunodeficiency Fig. 17.16 HIV Fig. 17.17 ...
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