a&p chapter 16

exam 3

Discuss the location of the thymus

Mediastinum anterior to the aortic arch posterior to sternum extending from root of neck to pericardium

Discuss the function of the thymus

Houses lymphocytes and differentiates thymocytes into T lymphocytes

Discuss the location of the spleen

Upper left abdominal cavity inferior to diaphragm posterior and lateral to stomach

Discuss the function of the spleen

Houses macrophages removes damaged red blood cells contains lymphocytes and acts as blood reservoir

List innate body defense mechanisms

Skin mucus membranes chemical barriers fever natural killer cells phagocytes and inflammation

Describe the action of skin

Acid mantle inhibits bacteria and keratin forms tough barrier against pathogens

Describe the action of mucous membranes

Trap microbes mucus tears and saliva contain lysozymes connective tissue slows pathogens

Describe inflammation

Walls off infection white blood cells destroy pathogens fibrin network forms phagocytes remove dead cells and tissues repair

Describe chemical barriers

Interferon produces antiviral proteins complement proteins destroy pathogens by cytolysis and opsonization

Describe natural killer cells

Lymphocytes that destroy virus infected and cancer cells using perforins and enhance inflammation

Describe phagocytosis

Phagocytes remove foreign particles neutrophils and monocytes most active monocytes become macrophages chemotaxis attracts cells

Describe fever

Pyrogens from macrophages reset hypothalamus and increase body temperature

What are the two major types of lymphocytes

T cells and B cells

How are T cells formed

Originate in red bone marrow mature in thymus then released into bloodstream

How are B cells formed

Originate and mature in red bone marrow then released into bloodstream

How are T cells activated

Antigens presented by antigen presenting cells trigger multiplication and immune response

How are B cells activated

Bind to specific antigen and receive helper T cell signals to multiply and produce antibodies

How do T cells function in immune mechanisms

Directly attack infected cells and regulate immune response

How do B cells function in immune mechanisms

Produce antibodies that bind antigens and mark pathogens for destruction

Describe primary immune response

First exposure antibodies appear in 5 to 10 days memory B cells produced

Describe secondary immune response

Faster response 1 to 2 days higher antibody levels memory cells respond quickly

Describe active immunity

Permanent immunity from antigen exposure memory cells produced

Describe passive immunity

Temporary immunity from antibodies no antigen exposure no memory cells