What are the major elastic/large arteries?
Aorta and its branches and the pulmonary arteries
What makes up the majority of the tunica media in medium sized arteries?
Smooth muscle cells
What type of blood vessels are more prone to dilation, external compression, and penetration by tumors or inflammatory processes?
What types of arteries are most commonly affected by atherosclerosis?
Elastic and muscular arteries
What types of arteries are most commonly affected by hypertension?
Small muscular arteries and arterioles
Do smooth muscle cells synthesize ECM molecules like collagen, elastin, and proteoglycans?
What are the three types of arteriosclerosis? Define each.
- Atherosclerosis: Hardening of medium and large (elastic) arteries due to accumulation of lipid in the tunica intima, leading eventually to fibrosis and calcification.
- Monckeberg’s arteriosclerosis aka medial calcific sclerosis: Involves peripheral muscular arteries, especially in lower limbs. Calcium deposits in the tunica MEDIA - not usually clinically significant.
- Arteriolosclerosis: Atherosclerosis of small arteries and arterioles, seen in chronic hypertension and DM. Causes downstream ischemic injury.
What are four non-modifiable risk factors for atherosclerosis?
Age, gender, family history, genetics
What did Dr. Kwan say is a very good indicator for atherosclerosis prognosis?
Is estrogen protective against atherosclerosis?
Describe the response-to-injury hypothesis of atherosclerosis pathogenesis.
Atherosclerosis develops due to a chronic inflammatory response of the arterial wall to endothelial injury. It progresses through aggregation of platelets, macrophages, smooth muscle cells and build up of lipids in the tunica intima. Macrophages eat lipids and turn into foam cells, etc.
Which cell type is primarily responsible for the synthesis of ECM molecules in the tunica intima of an atherosclerotic plaque?
smooth muscle cells
What is an atheroma?
The characteristic lesion of atherosclerosis. The accumulation of macrophages, lipids, calcium, smooth muscle cells, and fibrous CT in the tunica intima that result in arterial stenosis.
Does the endothelium need to be denuded for early atherosclerotic lesions to form?
Nope. This is the case most often
Where do plaques generally tend to occur?
Where there is a higher risk for turbulent flow like at branch points and along the posterior wall of the abdominal aorta.
What is dyslipoproteinemia?
Gene mutation that causes increased LDL, decreased HDL, higher risk for atherosclerosis
What is a fatty streak?
The first stage of atherosclerosis: lipid-filled foam cells that aren’t raised into the lumen and don’t disturb flow. An atheroma evolves from the fatty streak.
Name five vessels that are commonly affected by atherosclerosis in descending order.
- Lower abdominal aorta
- Coronary arteries
- Popliteal arteries
- Internal carotid
- Vessels of the circle of Willis (cerebral arterial circle)
In the very early stages of development of the atherosclerotic lesion, is lipid present?
No, just proliferating smooth muscle cells and ECM molecules.
Describe the cellular component of a fatty streak.
Many foam cells, smooth muscle cells (with a little fat, not too much)
What are the three principal components of atherosclerotic plaques?
- Cells: macrophages, smooth muscle, T cells
- ECM: collagen, elastic fibers, proteoglycans
- Intra and extracellular lipid
What is the superficial fibrous cap of an atherosclerotic plaque comprised of? What is found around it?
Smooth muscle cells and dense collagen. Underneath and at the shoulder there are macrophages, T cells and more smooth muscle cells. Deep to that is the necrotic core with fat, foam cells, cholesterol clefts, ECM molecules.
Rupture, ulceration, or erosion of the luminal surface of a plaque can cause _________ formation.
What is the difference between a true aneurysm and false aneurysm? What is a dissecting aneurysm?
Bulging of a vessel is a true anuerysm. A false aneurysm is weakness in three walls, with a hematoma forming inside the extravascular tissue. A dissecting aneurysm is when blood extravasates and forms a hematoma between two of the vessel walls.
____% blockage of an artery results in critical stenosis, where chronic hypoperfusion causes serious effects.
What are the two major causes of aortic aneurysms?
Atherosclerosis and hypertension.
Name three genetic mutations that can cause aneurysms.
- TGF-beta receptor mutation that affects elastin-collagen interaction.
- Mafran (fibrillin)
- Ehlers-Danlos (collagen)
What are the three classifications of aneurysms?
DeBakey I, II, and III
Monckeberg’s medial calficic stenosis affects ________ arteries, especially in the lower extremities. It is not usually clinically significant.
Hyaline atherosclerosis affects _________ and _______ and is characterized by a homogenous pink hyaline thickening of the walls with loss of underlying structural detail and lumen narrowing.
small arteries and arterioles
Hyperplastic arteriosclerosis is seen in severe ________ and is characterized by “onion skin:” concentric laminations of smooth muscle cells and BM resulting in thickened arteriole walls with luminal narrowing.
Do early fatty streaks have a fibrous cap/covering?