Section III: Innate Immunity

Question 0

How does the skin provide protection

Answer 0

• dermis is tightly woven fibrous connective tissue
• outermost cells contain water repelling keratin creating an arid environment
• outermost cells continually slough off taking with them microbes that are adherent

Question 1

What are the first line defenses of innate immunity

Answer 1

• Skin
• Mucous membranes
• Antimicrobial substances
• Normal flora

Question 2

How do the mucous membranes provide defense

Answer 2

• intestinal tract produces various enzymes and acid to retard microbes. IgA immunoglobulin in mucous
• cilia lining respiratory surfaces beat constantly upward to propel microbes to throat to be swallowd
• flow of urine flushes microbes from UT

Question 3

What are the antimicrobial substances that act as first line defenses

Answer 3

• sweat: evaporates and leaves salty residue
• lysozyme: enzyme in tears, saliva, and respiratory secretions, degrades peptidoglycan, so more effective against gram pos.
• Acid in stomach: kills many ingested bacteria

Question 4

How does the normal flora act as a first line defense

Answer 4

• provide considerable protection
• competitive exclusion of pathogens
• production of toxic compounds

Question 5

What are the sensor systems when the first line defenses have been breached

Answer 5

• Toll like receptors

- complement proteins

Question 6

What are toll-like receptors

Answer 6

• r/c recognize compounds unique to microbes
• each receptor (TLR#) recognizes small range of conserved molecules from a group of pathogens
• allows cell to send cytokines to other systems

Question 7

What are complement proteins

Answer 7

• series of proteins always present in blood that act in conjunction with adaptive defenses
• can become activated leading to a chain of events that results in microbe destruction

Question 8

What are phagocytes

Answer 8

cells that specialize in engulfing and digesting microbes

Question 9

What are macrophages

Answer 9

always present in tissue, can be recruited to site of injury, activated macrophages have greater killing power

Question 10

How do neutrophils behave in innate immunity

Answer 10

have more killing power than naive macrophages, rapidly recruited to site of injury

Question 11

What and how do NK cells kill

Answer 11

Kill tumor cells, and virus infected cells

• do not phagocytize
• inject perforin proteins into target cell to cause holes in target cell
• do not require activation, spontaneously kill target cell

Question 12

What is the process of inflammation

Answer 12

1: injury invasion
- cells sense and communicate trauma via cytokines. Bacteria may also release chemotactic factors that draw macrophages
- complement proteins also assist in sensing invasion
2: dilation of blood vessels
3: Fever
- induced by cytokines, or bacterial endotoxin