STUDY GUIDE: INNATE vs. ADAPTIVE IMMUNITY
INNATE IMMUNITY (Nonspecific / First Line of
Defense)
Key Characteristics
● Present at birth
● Immediate response
● Nonspecific (same response regardless of pathogen)
● No memory
Natural Barriers (First Line of Defense)
Physical Barriers
● Skin
● Epithelial cells lining:
○ GI tract
○ GU tract
○ Respiratory tract
● Normal microbiome (normal flora) prevents pathogen overgrowth
, Mechanical Barriers
● Sloughing of dead skin cells
● Coughing
● Sneezing
● Vomiting
● Urination
● Temperature & pH
○ Acidic environments reduce pathogen survival
Chemical / Biochemical Barriers
● Acidic protective substances:
○ Mucus
○ Tears
○ Sweat
○ Earwax
○ Saliva
● These contain lysozymes (lysosomes) → destroy bacterial cell walls
● Sebaceous glands secrete:
○ Fatty acids
INNATE IMMUNITY (Nonspecific / First Line of
Defense)
Key Characteristics
● Present at birth
● Immediate response
● Nonspecific (same response regardless of pathogen)
● No memory
Natural Barriers (First Line of Defense)
Physical Barriers
● Skin
● Epithelial cells lining:
○ GI tract
○ GU tract
○ Respiratory tract
● Normal microbiome (normal flora) prevents pathogen overgrowth
, Mechanical Barriers
● Sloughing of dead skin cells
● Coughing
● Sneezing
● Vomiting
● Urination
● Temperature & pH
○ Acidic environments reduce pathogen survival
Chemical / Biochemical Barriers
● Acidic protective substances:
○ Mucus
○ Tears
○ Sweat
○ Earwax
○ Saliva
● These contain lysozymes (lysosomes) → destroy bacterial cell walls
● Sebaceous glands secrete:
○ Fatty acids
