Chapter 21 Defenses Flashcards
External membranes
Skin and mucosa
Pathogen
Disease carrying microorganism
Lymph tissue guards
Tonsils, peyers patches, scattered embedded lymph tissue
Two lines of defense
Surface barriers
Internals ellipse and chemical
First line of defense
Epidermis and mucosa
Epidermis mechanical barrier
Stratified squamous epithelium is impermeable to water
Keratin
Resists against acids, bases, bacterial enzymes and toxins
Acid mantle in sweat and sebum is ___ to bacteria
Toxic
Mucosa mechanical barrier
Stratified squamous epithelium
Mucus
Traps microbes in the digestive and respiratory tracts
Nasal hairs
Filters and traps microbes
Cilia
Upper Respitory tract propels debris upwards to keep it away from lower resp. Tract
_____, _____, and ______ wash away microbes and contain lysozyme enzyme which killed microbes
Saliva
Sweat
Lacrimal secretions
Gastric juices
HCl and protein digesting enzymes kill microbes
Vaginal and urethra acidity inhibits
Bacteria and fungi growth
Phagocytes
Macrophages and neutrophils
Phagocytosis
Cytoplasmic extensions (pseudopods) engulf foreign matter forming a phagosome vacuole. Lysosomes joins up with phagosome and releases digestive enzymes, destroying microbe with release of residual material.
Macrophages
Wander free in the Extracellular spaces or are fixed in tissues (monocytes in lung alveoli, microglia in the brain and Kupffer cells in the liver)
Neutrophils
Phagocytic; but destroys themselves in the process
Pathogen capsule
A complex covering that identifies microbes as foreign. May make some bacteria hard to adhere to, so first needs an opsonizaton
Opsonizaton
Coating the pathogen capsule with complement protein or antibodies to aid adherence of phagocytes
Natural killer cells are
Nonspecific; Unique lymphocytes
Function of natural killer cells
Kills tunors and virus infected body cells
Natural killer cells mode of killing
Cytolytic chemicals penetrate invader’s membrane; not by phagocytosis
Parts of anti microbial proteins
Interferons and complement system
Interferons
Group of proteins made by WBCs and fibroblasts
Viral infected cells send interferon out from infected cells to
Non infected
Neighboring cells
Synthesize a chemical that interferes with viral replication
Complement system
Group of plasma proteins
Cell lysis
Creates stable hole in pathogen membrane
Opsonizaton
Coats membrane to aid adherence of phagocytes
Inflammation
Stimulates histamine release to enhance inflammation
Chemotactic
Attracts phagocytes to the area
Inflammation causes
Injury from trauma, heat, chemicals, or infection
Purpose of inflammation
Prevent spread, dilute, and dispose of pathogens, healing chemicals into area for time to repair
Cardinal signs of inflammation
Redness from hyperemia(blood to area) Heat from hyperemia; ups metabolism Swelling(edema) from exudate Pain from pressure, toxins, and chems Sometimes loss of function
Stages of inflammation (3)
Increased vasodilation and vascular permeability
Phagocyte mobilization
Tissue repair
Fever
Systemic reaction to infection
Benefits of low grade fever
Increased metabolism speeds up defense repair reaction rates
High fever is
Dangerous because of enzymes
Adaptive body defense
Immunities
Properties if adaptive defense
Recognizes antigens and acts with either a specific B or T lymphocyte
Works with nonspecific defenses
Has a memory
2 types of immunity
Humoral (antibody mediated)
Cellular (Cellmediated)
Cellular immunity usually for
Viruses
antigens
Non self molecules, mobilized immune response
Exogenous vs endogenous
Exo- invading foreign antigen
Endo- virus or cancer
Immunogenicity
Ability to stimulate an immune response
Reactivity
Ability to react with immune system
Antigenic determinant
Certain parts bind to a particular antibody
Complete antigen
Large molecule; protein or nucleic acid
Incomplete antigen (hapten)
Small molecules can bind to hosts own protein, causing to have immunogenicity.
Major histocompatibility complex (MHC) proteins
Denote self vs nonself and signal immune system when invaders (viruses) hiding in our cells by processing and displaying them
Antigen presenting cells
Major initiators of adaptive immunity by engulfing foreign protein and presenting it on it’s surface for others (especially T lymphocytes)
Cells if immune system
B and T lymphocytes
B Lymphocytes
Become immunocompetent in bone marrow; humoral immunity (antibodies)
T Lymphocytes
Become immunocompetent in thymus; Cellmediated immunity (cell killing)
T Cell mediated response
Target intercellular invaders that antibodies can’t get to.
Either Helper T or Cytotoxic T
Helper T cells (CD4)
Release cytokines to
Nonspecific def. - increase macrophages activity
Humoral immunity- stimulate B cells to proliferate
Cellular immunity- stimulate cytotoxic T cells
Cytotoxic T Cells
Attach to and cause lysis (death
Suppressor T cells
Release cytokines to prevent activity of both T cells against self
Autograft
Same individual translate
Allograft
Same species transplant
Xenograft
Different species transplant
Tissue/antigen cross matching (histocompatibility testing)
Reduce as much self as possible for transplant
Immunosuppressive therapy
Suppress reactions to nonself transplants
Clinal selection
When antigen challenges a B lymphocyte, it becomes specific vs the microbe and multiples rapidly to either plasma or memory cells
Plasma cells vs memory cells
Plasma makes the antibodies
Memory cells speed up response next time microbe is met
Lag period of primary immune response
3-6 days. Antibodies peak at 10
Secondary response lag period
Hours, antibodies peak in 2 days
Antibodies function
Can’t destroy antigens themselves but can inactivate them and tag them by forming Ag-Ab complexes
Neutralization
Ab binds to Ag sites preventing bacteria or virus from targeting host cell
Agglutination
Invader cells are cross linked
Precipitation
Ab cross links soluble chemicals
Antibody classes
IgM IgA IgD IgG IGE
IgA
Found in body secretions; protect mucosa and skin
IgG
Most plentiful Ab; main antibody in lymph and blood
IgE
Cause tissue mast cells and basophils to release histamine mediating allergic reactions
AIDs
From HIV virus, attacks helper T cells causing opportunistic infections
Lymphoma
Lymph node cancer, depress lymph cell functions
Hypersensitivity
Immune system overprotects vs relatively harmless substances
