CH. 9 The Immune System & Defense Mechanisms

viral diseases

AIDS, hepatitis, encephalitis, rabies, influenza, colds, warts, chicken pox

prion diseases

Bovine spongiform encephalitis (BSE, mad cow disease, incurable), Creutzfeldt-Jakob disease (CJD)

phagocytic cells

WBCs that surround and engulf invading bacteria (neutrophils, macrophages, eosinophils)

B lymphocytes

antibody-mediated immunity, make antibodies that bind with and neutralize specific antigens, active against viruses, bacteria, and soluble foreign molecules

interferons

antiviral proteins

antigen

any substance that triggers an immune response, usually a protein of a polysaccharide on the outer surface of an invading cell or virus

living pathogens

bacteria (unicellular prokaryotes), fungi (uni and multicellular eukaryotes), parasites (unicellular and multicellular eukaryotes)

T lymphocytes

cell-mediated immunity, directly attack foreign cells, coordinate immune response, active against parasites, viruses, fungi, intracellular bacteria, cancer cells, cells with "non-self" MHC

cytotoxic T cells

directly attack/destroy abnormal cells and foreign cells (tumor or viral-infected)

pathogens

disease causing organisms

viruses

extremely small infectious agents, smaller than bacteria, open to debate whether living or not, unable to reproduce outside a host cell, no metabolic activity, contain DNA or RNA but not both at once, nucleic acid is surrounded by a protein coat

transmissibility

how easily a pathogen is passed from person to person

virulence

how much damage is caused by the infection

prions

infectious proteins; normal proteins that aren't folded correctly, resist cooking/freezing/drying

components of lymphatic system

lymphatic vessels that transport lymph, lymph nodes that cleanse lymph, spleen to cleanse blood, thymus gland to facilitate maturation of T lymphocytes, tonsil and adenoids to protect throat

compliment proteins

lyse invading bacteria

functions of the lymphatic system

maintenance of blood volume in cardiovascular system, transport of fats/fat soluble material from digestive system, filtration of foreign material to defend against infection

2 types of B cells

memory cells (store info for future immune responses), plasma cells (actively secrete antibodies, which will bind to antigen) both are B cells activated when they recognize antigens

primary immune response

occurs on 1st exposure to antigen, lag time of 3-6 days for antibody production, peak at 10-12 days

secondary immune response

occurs on 2nd subsequent exposure to antigen, lag time in hours, peak in days

T cells

originate from stem cells in bone , mature in thymus, must be presented w/antigen by antigen-presenting cells (APCs)

non-specific defenses

phagocytic cells, inflammation natural cell killers, compliment proteins, interferons, fever response

examples of bacterial infections

pneumonia, tonsillitis, TB, botulism, toxic shock syndrome, syphilis, Lyme disease, etc. (all generally treated with antibiotics)

memory T cells

reactivate during later exposures

specific defense mechanisms (3rd of line defense/The Immune Response)

recognizes/targets specific pathogens and foreign substances, has "memory" and remembers initial exposure and responds more quickly and aggressively on subsequent exposures, able to distinguish between self cells and foreign invaders, healthy cells, abnormal/tumor cells

modes of disease transmission

respiratory, fecal, oral, body fluids

helper T cells

secrete cytokines which stimulate other immune system cells, play a key role in directing the immune response, are a target of the HIV infection

major histocompatibility complex (MHC) proteins

self-antigens that are on human cell surfaces enabling recognition of "self," enable immune system to distinguish "self" from "nonself"

characteristics of bacteria

single celled, prokaryotic, use a variety of resources for growth and reproduction

defense mechanisms

skin, stomach acid, tears, vomiting, phagocytosis, inflammation, immune response, antibodies, T cells

1st line defenses

skin, tears, ear wax, mucus, stomach, vagina, vomiting, resident bacteria, urination, defecation

inflammation

swelling, warmth, redness, pain

natural cell killers

types of lymphocytes that attack tumor cells and virus infected cells

nonliving pathogens

viruses, prions