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