9.21 Injury, Inflammation, Healing 8

Question 1

What are the chemical mediators of inflammation?

Answer 1

• histamine
• platelet-activating factor
• arachidonic acid derivatives
• cytokines
• blood coagulation, fibrinolytic, and complement systems

Question 2

What are histamines?

Answer 2

mast cells circulating in the bloodstream

Question 3

What is the function of the blood coagulation, fibrinolytic, and complement systems?

Answer 3

3 main blood systems that help in mediating inflammation

Question 4

Mast cell synthesizes and stores this

Answer 4

histamine

Question 5

What does histamine do?

Answer 5

• increases blood vessel permeability
• allows fluids and blood cells to flow into interstitial spaces
• potent vasodilator and bronchoconstrictor

Question 6

histamine: time frame

Answer 6

• quick action

- lasts less than 30 mins

Question 7

What does platelet-activating factor do?

Answer 7

• induces platelet activation and secretion
• activates smooth muscle cells, endothelial cells, and leukocytes
• strengthens activity of other inflammatory mediators

Question 8

How do platelet-activating factors strengthen the activity of other inflammatory mediators?

Answer 8

by bringing the others in to the area

Question 9

How many pathways does arachidonic acid follow?

Answer 9

2

Question 10

How does arachidonic acid go into the 2 pathways

Answer 10

• split off from damaged cell’s membrane phospholipids

- metabolized into one of two pathways

Question 11

What are the arachidonic acid pathways?

Answer 11

• cyclooxygenase (COX) pathway

- lipooxygenase pathway

Question 12

Most NSAIDs control via this pathway

Answer 12

COX pathway

Question 13

COX pathway »

Answer 13

• prostaglandins

- thromboxanes

Question 14

prostaglandins involved in

Answer 14

• fever and pain responses
• vascular permeability
• neutrophil chemotaxis

Question 15

thromboxanes involved in

Answer 15

• vasomotor tone

- platelet aggregation

Question 16

lipooxygenase pathway »

Answer 16

leukotrienes

**respiratory response

Question 17

leukotrienes involved in

Answer 17

• bronchoconstriction

- seen in later stages of inflammation

Question 18

How do leukotrienes behave with respect to bronchoconstriction?

Answer 18

• similar to histamine
• slower, longer response
• later stages of inflammation only

Question 19

What happens if we shut things down above arachidonic acid?

Answer 19

don’t get COX pathway or lipooxygenase pathway responses

Question 20

What is a med that shuts down arachidonic acid pathways?

Answer 20

steroids

Question 21

If the body perceives an appropriate level of circulating steroids, what happens?

Answer 21

• won’t produce more

- get a crash

Question 22

If the body perceives an appropriate level of circulating steroids, what happens?

Answer 22

• won’t produce more

- get a crash

Question 23

Cytokines are produced by

Answer 23

leukocytes

Question 24

examples of cytokine types

Answer 24

• IL-1
• interleukins
• tumor necrosis factor (TNF)

Question 25

IL-1 and interleukins have these types of actions

Answer 25

local and systemic inflammatory actions - metabolic - hemodynamic - hematologic

Question 26

tumor necrosis factor (TNF) is involved with these processes

Answer 26

- cell proliferation, differentiation, apoptosis - lipid metabolism - coagulation - can induce many IL-1 factors except activation of lymphocytes

Question 27

What are the 3 systems of clotting and bleeding?

Answer 27

- blood coagulation - fibrinolytic - complement

Question 28

coagulation system

Answer 28

assembles and dissembles clots

Question 29

fibrinolytic system

Answer 29

dissolves clots

Question 30

complement system

Answer 30

inflammatory mediators

Question 31

Where does phagocytosis fit in?

Answer 31

included with the clotting/bleeding systems because all chemical mediators attract phagocytic cells for removal of dead tissue/microorganisms as part of tissue healing

Question 32

Why don't you want continued clotting?

Answer 32

blood vessel will become occluded