Pathophysiology of Atherosclerosis Flashcards
(39 cards)
What causes atherosclerosis?
The slow, excessive buildup of plaque on the arterial endothelium, which hardens and narrows the arteries.
What are contained in the plaques?
Lipids, inflammatory cells, smooth muscle cells, and connective tissue.
What are the narrowing of the arteries in the legs, arms, stomach, and head called?
Peripheral artery disease
What is it called when there is narrowing of the arteries of the blood vessels that supply blood and oxygen to the heart?
Coronary artery disease, or CHD.
Blood vessel anatomy: What is the outermost layer around the blood vessel called? What is it made up of?
The adventitia. It is made up of connective tissue.
What is the first visible lesion in the development of atherosclerosis?
A fatty streak.
Blood vessel anatomy: What is the middle layer around the blood vessel called? What is it made up of?
It is called the media. It is made up of an external elastic membrane and smooth muscle.
Blood vessel anatomy: What is the innermost layer around the blood vessel called?
The intima. It contains an internal elastic membrane, and is located over the endothelium.
What is the role of the endothelium?
- It acts as a barrier between the blood and the rest of the vessel wall.
- Also, it secretes proteins onto its surface to prevent clotting.
What are the steps in atherosclerosis?
- Irritants (lipids, toxins, hypertension)
- Damage of endothelium
- Cholesterol deposits in endothelium - LDL-c
- Monocytes - macrophages - foam cells
- Plaques
What are form cells?
Monocytes that have become activated to macrophages, that have started to remove plaque and then “died.” These dead macrophages are called foam cells.
What are fibrous caps?
Smooth muscle that has migrated into the blood vessel to cover the plaque formation. Smooth muscle cells also deposit calcium into the plaque which causes hardening of the arteries.
What causes a fibrous cap to rupture?
A necrotic core forms if dead cells are not transported or disposed of properly. This includes the cholesterol, calcium, and foam cells. Growth factor secretions also contribute to the plaque rupture. Clotting factors are produced when the plaque is exposed to the blood, and a clot forms (thrombus), preventing blood flow through the vessel.
What contributes to atherogenesis?
Excess of dietary fat and cholesterol.
What does vascular endothelium do?
Important in vascular tone (through NO production), platelet aggregation, inflammation, oxidation, and cellular proliferation. permeability barrier, regulate thrombosis,
What does migration and retention of lipoproteins in the arterial wall cause?
Helps initiate atherosclerosis.
Do all plaques rupture? What makes them rupture?
Large necrotic core, many inflammatory cells, thin fibrous cap. Usually a cause of acute coronary syndrome.
What does a thrombin consist of?
Platelets and fibrin
What are some modifiable risk factors for atherosclerosis?
cigarette smoking LDL <40 High HDL Diabetes Obesity Physical inactivity
What are some non-modifiable risk factor for atherosclerosis?
men>45 years
women post-menopause, >55 years
FH of CHD (male 1st degree <55yr, female 1st degree <65 yrs)
What adjusted odds ratio is the most important for risk of MI?
ApoB/ApoA ratio
What does an adjusted odds ration of >1 mean? <1?
> 1 means there is a risk, <1 means protective effect as long as the CI doesn’t cross one.
What molecular markers are emerging?
Lipoprotein a = Lp(a) High-sensitive creative protein (Hs-CRP) small-dense LDL (metabolic syndrome) Plasminogen Activator inhibitor-1 Apo-B lipoprotein-associated phospholipase A2 Vitamin D deficiency
What is the process of NO production?
- eNOS releases NO (endothelium nitric oxide synthase)
- NO activates guanylyl cyclase
- Guanylyl cyclase catalyzes GTP to GMP
- cGMP gets Ca into SR
- Smooth muscle relaxer and vessel dilates
