Chapter 14 Flashcards
Functions of a healthy functioning immune system
Surveillance, recognition, destruction
Surveillance
Surveillance of the body
Recognition
Recognition of foregin material
Destruction
Destruction of entities deemed to be foreign
Defense mechanisms of the host
Innate, natural defenses and adaptive immunities
Innate natural defenses
Present at birth, provide nonspecific resistance to infection ( general response)
Adaptive immunities
Specific, must be acquired
Defense mechanisms of the host
First line of defense, second and third.
First line of defense
Barrier that blocks invasion at portal of entry, NONSPECIFIC, INNATE
Second line of defense
Protective cells and fluids, inflammation and phagocytosis, NONSPECIFIC, INNATE
Third line of defense
Produces protective antibodies and creates memory cells, SPECIFIC, TARGETED , ADAPTIVE
Physical barriers first line of defense
Skin; highly impervious and waterproof
Tears, saliva, urine; physically flush out microbes ( mechanically flush fluid)
Mucous membranes; line the respiratory, digestive, reproductive and unitary tract
Resident bacteria/ normal flora: take up space, inhabit the body use available nutrients and space
Defense of respiratory tract
- Mucous coat attachment and entry of bacteria
- nasal hair traps larger particles
Chemical first line of defenses
- sebaceous secretions ( sweat, pH)
- LYSOZYME; enzyme hydrolyzes cell wall of bacteria in tears
- High lactic acid and electrolyte in sweat ( sweat=salty)
- skin acidic pH
- hydrochloric acid in stomach ( low pH)
- digestive juices and bile
- semen contain antimicrobial chemical
Genetic defenses
Some host genetically immune to disease of other hosts
