Week 12 - Human Defense

innate defense

always active; 1st and 2nd lines of defense; present at birth

acquired (adaptive) defense

must be stimulated to become active; 3rd line of defense; immune system learns how to attack antigens and develops memory; specific immunity attacks specific antigens

physical barriers

unbroken skin; mucous membranes (eyes, nose, mouth, respiratory, vagina, GI tract)

mechanical barriers

movement of cilia, sticky nature of mucus, hair in nose, coughing, sneezing, shedding of skin cells and mucous membrane cells

antimicrobial chemicals

HCI in the stomach, organic acid on the skin and vagina, interferon, complement system (special group of proteins in blood and tissue fluids, working with immune response)

cellular barriers

phagocytes (neutrophils and macrophages)

antigens

foreign to the body; activate the immune responses (bacteria, viruses, fungi, protozoa)

lysosome

enzyme produced in sweat, tears, saliva kills bacteria

gastric juices

stomach acid kills bacteria and toxins

saliva

dilutes mo’s and washes oral cavity

phagocytosis

phagocytes destroy microbes in body tissues

inflammation

localized response to damage

fever

response to infection that inhibits bacterial growth and increases rate of repair

3rd line of defense

relies on antigens found in foreign microbes to initiate response

t-lymphocytes

cell mediated response; helper t cells (activate more wbcs, driving force in maintaining defense system) and killer t cells (track down cells infected with viruses)

b-lymphocytes

antibody mediated response; memory cells; plasma (produces antibodies)

white blood cells

cells of the immune system; protect body against infectious diseases and foreign invaders; aka leukocytes

lymphocytes, monocytes, neurophils, eosinophils, basophils

what are the 5 main types of wbc?

lymphocytes

more common in lymph than in blood; have longest lifespan (memory cells); includes b cells and t cells

monocytes

largest wbc; phagocytic; turn into macrophages when they leave the bloodstream

neutrophils

most abundant wbc; first responders to bacterial, fungal infections; make pus; phagocytic; aka PMNs

eosinophils

found mostly in mucous membranes; deal with parasitic infections and allergic reactions

basophils

rarest of wbc; responsible for allergic and antigen response by releasing histamine

dental caries, periodontal disease, gonorrhea, common cold

what are some exceptions to getting infectious disease repeatedly?

artificial immunity

involves being immunized or vaccinated against a specific disease

damage by the immune system

activation of the immune system by certain antigens can cause damage to body

anaphylactic shock

allergy to a substance distributed throughout the body may result in a widespread reaction affecting the blood system, lungs and heart

contact dermatitis

cell-mediated allergic reaction (nickel, poison ivy, latex gloves)