Innate Immunity

Question 1

Two defense systems

Answer 1

-Nonspecific defense system (innate immunity)
-Specific defense system (adaptive immunity)

Question 2

Immunity

Answer 2

Ability to resist or eliminate potentially harmful foreign invaders

Question 3

Innate Immunity

Answer 3

-Physical barriers
-Chemical barriers
-Cellular defenses

Question 4

First line of defense of innate immunity

Answer 4

Barrier defenses

Question 5

Innate immunity

Answer 5

Protection from or resistance to infection by non-immune response mechanisms

Question 6

Body coverings

Answer 6

-Intact skin (contains keratin - structural protein that helps form protective barrier)
-Mucous membrane (trap pathogens)

Question 7

Chemicals produced by the body

Answer 7

-Acid in the stomach
-Fatty acids and secretion form tears, sweat, and oil glands are toxic to bacteria and fungi

Question 8

Barrier defenses

Answer 8

-Trachea lined with ciliated cells and cells that secrete mucus
-Esophagus leads to stomach with a pH of 1-2 (acidic) which kills most pathogens
-Urinary tract has lower pH (acidic) and is flushed with urine
-Tear ducts with lysozymes
-Reproductive tract also has a lower pH (acidic)

Question 9

Stomach mucosa

Answer 9

-Secretes hydrochloric acid
-Has protein-digesting enzymes (these kill many bacteria)

Question 10

Barrier defenses

Answer 10

-Saliva and lacrimal fluid contains lysozyme (an enzyme that catalyzes the destruction of the cell walls of certain bacteria)
-Mucous traps microorganisms in digestive and respiratory pathways

Question 11

Phagocytes

Answer 11

1. Neutrophils : most abundant WBC
2. Monocytes/macrophages
   -Engulfs foreign material into a vacuole
   -Enzymes from lysosomes digest the
   material

Question 12

Natural killer cells

Answer 12

-Can lyse and kill cancer cells
-Can destroy virus-infected cells

Question 13

Immune cells that are granulocytes

Answer 13

Neutrophils, basophils, eosinophils

Question 14

Chemical responses (#1)

Answer 14

1. Kinins or chemokines (microbial peptides) are released by certain phagocytes
   -These molecules increase circulation and capillary permeability
   -Attract leukocytes to site of injury
   -Affect nerve cells making area tender

Question 15

Chemical responses (#2)

Answer 15

2. Complement proteins (approx. 30 proteins) work by a number of different methods
   -These proteins create pores in invading bacteria, causing water to rush in

Question 16

Chemical responses (#3)

Answer 16

3. Interferons secreted proteins made by virus-infected cells. Bind to healthy cell surfaces to inhibit virus bonding

Question 17

Chemical responses (#4)

Answer 17

4. Histamine is released by mast cells and basophil cells which are attracted to an injury site. When the skin is penetrated, cells are ruptured releasing chemical signals to attract the mast and basophil cells. These cells release histamine

Question 18

Second line of defense

Answer 18

inflammation

Question 19

Inflammation

Answer 19

-Increases capillary permeability. The area becomes swollen, red, temp increases from the increased blood flow
-Phagocytes leave the capillary bed because they are attracted to histamine and other signals
-Phagocytes clean up pathogens and cell debris

Question 20

Homeostasis and inflammatory response

Answer 20

-Inflammation continues as long as the triggers (pathogens) are present
-When phagocytes complete their job by removing the pathogens, macrophages begin to secrete substances that: suppress inflammation, promote tissue repair

Question 21

Fever

Answer 21

-Abnormally high body temp
-Hypothalamus heat regulation can be reset by pyrogens (response to pathogens proteins and secreted by WBCs)
-High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria
-Fever also increases the speed of tissue repair