Inflammation & Wound Healing

Question 1

T/F: Necrotic or dead tissue can mount an inflammatory response.

Answer 1

False.

Question 2

What are the 5 Cardinal Signs of inflammation?

Answer 2

1. Calor (heat)
2. Rubor (redness)
3. Tumor (swelling)
4. Dolor (pain)
5. Functio laesa (loss of function)

Question 3

Describe the Circulatory changes that occur in inflammation.

Answer 3

• 1st response = changes in blood flow
• mechanical stimulus (burn) –> nerve signals smooth muscle cells to relax on pre-capillary arterioles –> inflow of blood to capillaries (RBC’s single file line)
• results in redness, swelling, and warmth

Question 4

Describe the Circulatory changes that occur in inflammation.

Answer 4

vasoconstriction of arterioles (seconds) –> vasodilation of pre-capillary sphincters (Redness and swelling) –> influx of blood flow & pressure leads to plasma filtration through vessel wall (edema) –> blood flow slows, due to hemoconcentration –> congestion of WBCs and RBCs

Question 5

What is “Rouleaux” formation and what type of cells undergo this change?

Answer 5

• sludged erythrocytes form stacks that impede and slow down circulation

Question 6

What is “Pavementing?”

Answer 6

when WBC’s marginate and become attached to the edge of the endothelium, which are anchored by platelets via fibrin strands

Question 7

What is one of the most important triggers for the release of mediators of inflammation (i.e Interleukins)?

Answer 7

• adhesion of leukocytes to the endothelial cells

Note: WBCs can stick bc they develop protrusions (pseudopods) on their surface

Question 8

What is the most common cell type in acute inflammation? What are these cells replaced by as inflammation proceeds into chronic stages?

Answer 8

Neutrophils or PMN’s

- lifespan is 2-4 days so replaced by macrophages, lymphocytes, and plasma cells

Question 9

What are the 4 phases of leukocyte emigration through the vessel wall? and what is this process called?

Answer 9

• “Chemotaxis”
  1. adhesion of PMN’s to endothelium
  2. Insertion of cytoplasmic pseudopods between junctions of the endothelial cells
  3. passage through basement membrane
  4. ameboid movement away from vessel toward cause of inflammation (i.e. bacteria)

Question 10

Describe cellular events involved in inflammation.

Answer 10

• PMN’s that reach bacteria or other sources of chemotactic substances, lose their mobility and begin “phagocytosis”
• PMN recognizes bacterium as foreign by pseudopods extending from surface of the PMN
• attachment of PMN cell membrane to bacterial cell wall; facilitated by immunoglobulins or complement acting as opsonins

Question 11

Many leukocytes have receptors for ___ and ___ which mediate contact with bacteria.

Answer 11

-C3 complement and Fc portion of immuno-globulin

Question 12

Dead and dying PMN’s + tissue debris forms ___ which are known as ___ inflammations.

Answer 12

• viscous yellow fluid called pus

- purulent or suppurative

Question 13

Describe characteristics of a fever and how it is mediated.

Answer 13

• body temperature exceeds 37 deg C
• caused by endogenous pyrogen
• Interleukin-I and Tumor Necrosis Factor (TNF) act on hypothalamus which serves as a thermostat
• PMN’s and macrophages release pyrogens (IL-2 & TNF) in hypothalamic center, which then release prostaglandins that mediate the fever

Question 14

Describe Leukocytosis.

Answer 14

• Normal blood is 10k WBC’s/mm3. Mediators of inflammation act on bone marrow stimulating rapid release of WBC’s.
• if > 12-15k then leukocytosis and in acute inflammation neutrophils predominate