Lecture 3

Question 1

Erythema

Answer 1

Redness and heat caused by vasodilation and increased blood flow to an area. Induced by histamine and nitric acid.

Question 2

Vascular permeability

Answer 2

Endothelial cells of vessel wall triggered by histamine, bradykinin, leukotrienes, substance P etc to contract, increasing inter-endothelial spaces. It is the immediate transient response.

Endothelial injury -> endothelial cell death causing damage in the vessel wall and allowing immediate extravascular leakage

Transcytosis leading to increased transport of fluids/proteins through cell channels. Promoted by specific factors triggered by inflammation e.g.. VGEF.

Question 3

Margination

Answer 3

RBC’s flow in the centre of the vessel lumen, WBC flow peripherally

Question 4

Rolling

Answer 4

Increased number of leukocytes along the edge of the damaged endothelium. Mediated by selectins

Question 5

Adhesion

Answer 5

Leukocytes stop and adhere to the endothelium. Cytokines secreted by injured cells encourage the adhesion of leukocytes.

Question 6

Transmigration

Answer 6

Leukocytes are encouraged to pass through endothelium -> extravascular space. Chemokine’s stimulate migration and leukocytes move towards chemical conc gradient.
PECAM-1 platelet endothelial adhesion molecule

Question 7

Chemotaxis

Answer 7

exogenous (bacteria) and endogenous (cytokines/complement) substances attract leukocytes towards the site of injury
Neutrophils arrive at 6-24h, monocytes at 24-48.

Question 8

Outcomes of inflammation

Answer 8

Complete resolution
Healing with connective tissue replacement (fibrosis)
Abscess formation
Progression to chronic inflammation

Question 9

Granulomas

Answer 9

Cellular attempt to contain offending agent it cannot contain.
Strong activation of macrophages and T lymphocytes leading to injury of normal tissues