CHAPTER 14: HOST DEFENSE

Question 1

Host Defenses in order

Answer 1

1. Anatomical & chemical immunity: mucus, saliva, stomach acid, tears, scabs
2. Intrinsic: autophagy, apoptosis, miRNA, CRISPRs
3. Innate: NK cells, complement, antigen-presenting cells, neutrophils
4. Acquired: T and B cells

Question 2

how do microbes circumvent the immune system?

Answer 2

• using counter measures APOBEC3 and HIV 1
• APOBEC3 is a cytidine deaminase (C to U base change)
• this interferes with HIV RT (reverse transcriptase) providing a specific defense against HIV

Question 3

First Line of Defense
- what is it
- what parts of body implement this
- specificity

Answer 3

• barrier blocks invasion at PORTAL OF ENTRY
• skin, mucous membrane, eyes, digestive tract
• outermost layer of skin/epithelial cells compacted with keratin
• flushing effect of sweating
• stomach acid
  (cholera sensitive to acid)

IT IS NON SPECIFIC

Question 4

Second Line of Defense
- what is it
- specificity

Answer 4

• protective cells and fluids
• inflammation and phagocytosis

IT IS NON SPECIFIC

Question 5

Third Line of Defense
- what is it
- specificity

Answer 5

• acquired with exposure to foreign substance
• produce protective antibodies and create memory cells

IT IS SPECIFIC

Question 6

Non Specific Chemical Defenses

Answer 6

born with them
- sebaceous secretions (sebum and acid mantle/film on the skin)
- lysozymes: enz in tears that hydrolyze peptidoglyc
- defensins: peptides made by cells that can damage cell membranes/lyse bac and fungi
- lactic acid and electrolytes in sweat
- HCl in stomach acid
- digestive juice/bile
- semen –> antimicrobial

Question 7

Genetic Defenses

Answer 7

• some hosts naturally immune to diseases of other hosts
• some pathogens have greater specificity

CCR5 mutation makes ppl resistant to HIV —> mutates receptor that HIV uses to get in

Question 8

Immunology is…

Answer 8

study of body’s second and third line defenses

Question 9

Functions of a healthy immune system

Answer 9

• surveillance of the body
• recognize foreign material
• destroy foreign entities

Question 10

WBC purpose

Answer 10

• leukocyte
• innate ability to recog and differentiate foreign material

Question 11

nonself vs. self

Answer 11

nonself=foreign material
self= healthy tissue

Question 12

PAMPs= pathogen-associated molecular pattern molecules

Answer 12

molecules are shared by microorganisms
- recognizes these patterns in pathogens

ex) LPS (lipopolysaccharide)

Question 13

PRR=pathogen recognition receptors

Answer 13

• receptors on WBC for PAMPs
• toll-like receptors (TLR)

Question 14

The immune system consists of

Answer 14

• network of cells and fluids that penetrate into every organ and tissue
• RES (reticuloendothelial system)
• ECF
• Bloodstream
• Lymphatic system