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PHYSIOLOGY (CH 19/40 – Human Immune Response)
Date:
CH 19: Bacteria & Viruses (p.470)
 Bacteria
o prokaryotic (unicellular, no nucleus) (fig 19-2)
o can be autotrophic or heterotrophic
o reproduce asexually by binary fission – parent splits to form 2 identical daughter cells
o can exchange genetic info by conjugation  ↑’s genetic variation (fig 19-5)
 Viruses
o require host cell to reproduce
 specific to cells they infect
o consist of DNA/RNA core & capsid (protein coat) (fig 19-9)
o NOT living things (fig 19-11)
40-1: Infectious Disease (p.1030)
*pathogens: disease-causing agents
 Treatment
o antibiotics: kill bacteria w/o harming human cells
 NOT effective against viruses
o antiviral drugs
o over-the-counter drugs- treat symptoms of disease (not cause)
 Prevention
o vaccines: preparation of weakened or killed pathogens that stimulates production of antibodies
 effective against bacteria AND viruses
Date:
40-2: The Immune System (p.1036)
*immunity: fighting infection by producing white blood cells (WBCs) that inactivate pathogens
 Nonspecific Defenses
o skin acts as barrier against infection, secretes oil & sweat to kill pathogens
o inflammatory response (fig 40-7)
 WBCs called phagocytes rush to injured/infected tissue to kill pathogens
o fever: elevated body temp slows or stops growth of pathogens
 Specific Defenses – the immune response
o humoral immunity –B cells provide immunity against pathogens in body fluids (fig 40-9)
 antibodies: proteins that recognize & attack specific pathogens (fig 40-8)
 memory B cells reduce chance that same disease could develop twice
secondary response leads to production of same antibodies
o cell-mediated immunity – T cells provide defense against pathogens inside infected cells (fig
40-10)
 memory T cells trigger secondary response if pathogen returns
Date:
40-3: Immune System Disorders (p.1043)
 immunodeficiency – compromised immune sys. cannot adequately fight infection
 AIDS – results from HIV
a. HIV evades immune sys. defenses
b. destroys helper T cells  body cannot defend against other pathogens