Immune Chapter Flashcards
Innate Defenses:
- General, non-specific defenses that all healthy
individuals are born with
Surface Barriers
Skin & mucosal membranes
Internal Defenses
Cells, Antimicrobial proteins, Inflammation, Fever
Innate Defenses: Surface Barriers
Function: Physically and chemically block the entrance of pathogens
External Surface Barrier: Skin
oSpecial Features: Keratinized, stratified squamous epithelium
oExternal Secretions: Sweat, sebum, hyaluronic acid
Internal Surface Barrier: Mucosa
oSpecial Features: Contains MALT
oInternal Secretions: Mucus, saliva, stomach acid (HCl), urine
Innate Defenses: Internal Defenses
- Cells
oPhagocytic, proinflammatory, apoptosis-initiating, parasite-destroying - Antimicrobial Proteins
oIFNs & complement proteins - Inflammation
- Fever
Phagocytic cells
engulf pathogens, foreign
particles, and cellular debris
Proinflammatory cells
release inflammatory chemicals to recruit
immune cells (leukocytosis)
Apoptosis-Initiating cells
secrete perforins to perforate target membranes.
Leads to targets lysing. Secrete granzymes to initiate
target apoptosis (cell suicide).
Parasite-Destroying cells
Secrete enzymes and toxins lethal to parasites
Antimicrobial Proteins: IFNs
Interferons (IFNs) interfere
with protein synthesis to
prevent viral replication.
It protects neighboring cells
from the spread of infection.
Antimicrobial Proteins: Complement
Opsonization
Complement proteins called opsonins bind and tag
targets to attract phagocytic cells
- Enhances Inflammation
Complement proteins activate mast cells and basophils
Complement proteins also attract neutrophils and
macrophages
Antimicrobial Proteins: Complement
- Enhances Cell Lysis (via MACs)
Complement proteins form large membrane channels
called Membrane Attack Complexes (MACs) to cause
cytolysis - Enhances Phagocytosis
Complement proteins link antibody-antigen complexes
to RBCs to be sent to the liver where macrophages will
eliminate the complexes
Inflammation
Immediate, localized response within vascularized
tissues