Cardiovascular 1 Flashcards
What are the different types of blood vessels and their functions?
- The aorta is a large blood vessel with a thick wall and elastic tissue because it has to withstand high pressure.
- As the blood goes forward it goes to smaller and smaller arteries, diameter gets smaller and walls get thinner (less elastic tissue),
- until the capillary which only have 1 layer in the wall since is made for exchange.
- Veins are bigger since they are made for capacity (at any moment they contain the majority of the blood in the body).
- They also have valves (in the larger ones) in order to control the one-way flow and can also contract to some extent.
What is atherosclerosis and what does it cause?
Atherosclerosis is a pathological change in the wall of the artery and is the fundamental cause of many circulatory problems. It causes cardiovascular disease and cerebrovascular disease.
Describe the timeline of atherosclerosis.
The initial event is endothelial injury and dysfunction, leading to the formation of a fatty streak. This can advance and buildup, leading to the abnormal buildup of atheroma (fibrous tissue) within the intima. This can progress from mild to moderate to severe, with plaques sticking into the wall of the aorta.
What are the consequences of atherosclerosis?
Atherosclerosis can be asymptomatic until highly advanced. It can cause angina, myocardial infarct, transient ischemic attacks, stroke, and peripheral arterial disease. The stability/fragility of the atherosclerotic plaque can also be determined depending on the thickness of the wall of the plaque.
What are capillaries made for?
They are made for exchange, hence they only have 1 layer in the wall.
What is the function of veins?
They are made for capacity and contain the majority of the blood in the body at any moment
What is a fatty streak in atherosclerosis?
It’s the normal lipid accumulation in proliferating intimal smooth muscle and extracellular matrix.
What happens in the preclinical phase of atherosclerosis?
There is formation of a normal fatty streak, which can advance and buildup, but no symptoms are felt as there is enough space for blood to flow.
What happens in the clinical phase of atherosclerosis?
This phase can involve rupture/fissuring of the surface of the plaque, erosion/ulceration, or hemorrhage in the plaque. All can lead to aneurysm and rupture of aorta, occlusion by a thrombus, or critical stenosis (complete block by fat).
What is a stable plaque in atherosclerosis?
A stable plaque has a small lipid core with a thick fibrous cap, allowing enough blood to pass through.
What is an unstable plaque in atherosclerosis?
An unstable plaque has a big lipid core with a thin fibrous cap, which has much more potential to rupture.
What is the function of valves in veins?
They control the one-way flow of blood.
What is the role of endothelial cells in blood vessels?
They release signaling molecules and can alter coagulation, inflammation, blood flow, etc. in response to injury or stress.
What is the consequence of a ruptured atherosclerotic plaque?
It can lead to aneurysm and rupture of aorta, occlusion by a thrombus, or critical stenosis.
What is an aneurysm in the context of atherosclerosis?
It’s a weakening of the wall of the blood vessel, which can rupture and cause significant bleeding.
What is the key component of multifactorial risk in pathogenesis?
The key components are endothelial dysfunction and chronic inflammation.
What is a critical feature in atherosclerosis?
Endothelial injury is a critical feature in atherosclerosis.
What may cause chronic endothelial injury?
Chronic injury may be due to hyperlipidemia, hypertension, smoking, etc.
What are the most vulnerable places for injury and plaque formations? Why?
Branch points are the most vulnerable places for injury and plaque formations since blood is flowing through here and has to hit the endothelial to diverge
What changes can inflammation within the arterial intima lead to?
It can lead to cytokine release promoting cellular changes.
What are the most important cells in the pathogenesis?
Macrophages and T-cells are the most important cells in the pathogenesis.
What happens when cells migrate through the altered endothelium into the intima?
They alter their properties, which can lead to injury induced smooth muscle cell proliferation
What are foam cells?
Foam cells are macrophages filled with lipids, which causes the buildup up lipid in the vessel wall.
What is the structure and function of lipoproteins?
Lipoproteins have an outside phospholipid membrane with cholesterol and is surrounded by different apoproteins. Inside is triglycerides and cholesterol esters but varies with their types. They have different functions based on their different apoprotein receptor signaling
What happens when oxidized LDL is internalized by scavenger receptors on macrophages within the intima?
Macrophages can then accumulate LDL and becomes foam cells. This also activates inflammatory response: releases cytokines, chemokines, ROS, etc.
What are the functions of smooth muscle cells?
They can accumulate lipid, become foam cells, and synthesize collagen, elastin, and glycoproteins
What changes can smooth muscle cells undergo?
They can change from contractile (normal) to secretory when responding to secreted factors. They can also exhibit many other phenotypes: mesenchymal, fibroblast, macrophage, osteogenic, adipocyte, contractile.
What is the result of hypercholesterolemia in the context of pathogenesis?
In hypercholesterolemia, monocytes attach and migrate along the wall of the vessel.
What happens when foam cells die?
If foam cells die, they then release all their accumulated lipid in the circulation.