Nichols- Atherosclerosis

Question 1

What is atherosclerosis

Answer 1

chronic inflammatory disease of tunica intima of arteries.. leads to hardening of arteries

Question 2

The hypothesized pathogenesis is response to injury. It consists of 5 steps, name them

Answer 2

1. Endothelial injury –> release of cytokines
2. Accumulation of LDL in intima –> oxidation of said LDL
3. Leukocyte & smooth muscle recruitment
4. Foam cell formation- macrophages take up oxidized LDL via scavenger receptors
5. ECM deposition

Question 3

First step of atherosclerosis pathogenesis?

Answer 3

Endothelial injury leading to cytokine release

Question 4

Step 2 of atherosclerosis pathogenesis?

Answer 4

Lipid accumulation in tunica intima. The LDL is recruited then oxidized

Question 5

Step 3 of atherosclerosis pathogenesis?

Answer 5

Recruitment of leukocytes and myocytes. The myocytes (smooth muscle cells) TRANSFORM into monocytes –> macrophages

Question 6

Step 4 of atherosclerosis pathogenesis?

Answer 6

Foam cell formation. The macrophages eat up all the oxidized LDL. It does this via SCAVENGER receptors, not LDL receptors.

Question 7

Why do macrophages gobble up all the oxidized LDL with scavenger receptors instead of LDL receptors and what is the significance of this?

Answer 7

Uses scavenger receptors because the LDL is not normal (oxidized) so macrophages cant use their normal LDL receptors. This is significant because LDL receptors have a limit to uptake via negative feedback. Scavenger receptors have no such limit. That is why the macrophages become big fat FOAM CELLS full of fat

Question 8

Step 5 of atherosclerosis pathogenesis?

Answer 8

ECM deposition

Question 9

Describe what a atheromatous plaque looks like

Answer 9

yellow/white fibrofatty lesion covered by white fibrous cap

Question 10

The atheroma itself (underneath the fibrous cap) is composed of?

Answer 10

FF ECS: fibrin, foam cells, eosinophilic debris, cholesterol clefts, smooth muscle cells

Question 11

The fibrous cap covering the atheroma is composed of?

Answer 11

MS LC: macrophages, smooth muscle cells, collagen, lymphocytes

Question 12

What 3 factors predispose to thrombosis superimposed on atherosclerosis?

Answer 12

1. Endothelial injury
2. Abnormal blood flow
3. Hypercoagulability

Question 13

When an atherosclerotic plaque ruptures, you get?

Answer 13

Thrombosis superimposed on atherosclerosis

Question 14

Describe an intraplaque hemorrhage

Answer 14

A blood vessel INSIDE the atherosclerosis bursts so the atheroma swells and further occludes the artery