how the CVS fails

Question 1

How does vessel size affect wall tension?

Answer 1

In a cylinder, wall tension is directly proportional to pressure times radius. Therefore, the larger the vessel, the greater the wall tension.

Question 2

What is vessel compliance?

Answer 2

Vessel compliance is the change in volume caused by a change in pressure.

Question 3

Does vessel compliance change with age or wall pathologies?

Answer 3

Yes, vessel compliance decreases with age and with wall pathologies like atherosclerosis and calcification.

Question 4

What conditions may cause turbulent flow in vessels?

Answer 4

Turbulent flow is more likely with increased velocity and low fluid viscosity. It may be caused by junctions, obstacles, or mixing.

Question 5

What is turbulent flow, and how does it differ from laminar flow?

Answer 5

Laminar flow refers to the smooth, even movement of fluid through a vessel. Turbulent flow, on the other hand, is more chaotic and disorganized, with faster velocities and lower fluid viscosity. Turbulent flow can be caused by vessel branching, foreign bodies, or mixing defects.

Question 6

What is an aneurysm, and how can it be caused?

Answer 6

An aneurysm is an abnormal bulging or ballooning of a blood vessel. Aneurysms can be caused by factors like genetic predisposition, atherosclerosis, infection, or trauma. They can also be associated with hypertension or other cardiovascular diseases.

Question 7

How is aneurysm treated, and what are the potential risks and complications of treatment?

Answer 7

Treatment of aneurysms depends on their size, location, and potential risks. Some aneurysms may be treated with medications, while others may require surgical intervention. Risks of treatment can include bleeding, infection, and damage to surrounding tissues or organs.

Question 8

What is atherosclerosis?

Answer 8

Atherosclerosis refers to the build-up of fats, cholesterol, and other substances in and on the artery walls (plaque), which can restrict blood flow.

Question 9

What is the structure of the arterial wall?

Answer 9

The arterial wall has three layers:
- adventitia
- media
- has external elastic membrane
- smooth muscle
- internal elastic membrane
- intima
- endothelium is the innermost part

Question 10

What is the ischaemic cascade?

Answer 10

The ischaemic cascade is the sequence of events that occur when there is a lack of oxygen supply to the heart muscle, and it includes hypoperfusion, metabolic disturbance, arrhythmia, diastolic dysfunction, systolic dysfunction, acute heart failure, ECG changes, chest pain, and myocyte necrosis.

Question 11

What is a vulnerable plaque?

Answer 11

A vulnerable plaque is a type of plaque with a thin cap that covers a lipid-rich core. It is more likely to rupture and expose the collagen and lipid, which can activate the platelets and the blood clotting pathways, leading to coronary thrombosis.

Question 12

What is coronary thrombosis?

Answer 12

Coronary thrombosis is the formation of a blood clot inside a coronary artery, which can lead to a heart attack.

Question 13

What is the role of endothelial function in vessel health?

Answer 13

The endothelium plays an important role in maintaining vessel health. It helps control vessel tone, perfusion, and thrombogenicity, and it also secretes antithrombotic factors and regulates capillary filtration. Nitric oxide and prostacyclin are vasodilator substances released by the endothelium.

Question 14

What is plaque rupture?

Answer 14

Plaque rupture occurs when the thin cap covering a plaque breaks, exposing the collagen and lipid, which can activate the platelets and the blood clotting pathways, leading to coronary thrombosis.

Question 15

What are the stages of atherosclerosis?

Answer 15

The stages of atherosclerosis are fatty streak, fibrous plaque, occlusive atherosclerotic plaque, and plaque rupture.

Question 16

What happens during a myocardial infarction?

Answer 16

During a myocardial infarction, plaque rupture can occur, exposing collagen and lipid, which can trigger platelet adhesion and activation of the blood clotting system. This can lead to the formation of a blood clot (thrombus) that can occlude the coronary artery and cause ischemia, leading to a cascade of events that can include hypoperfusion, metabolic disturbances, arrhythmias, diastolic and systolic dysfunction, ECG changes, chest pain, and myocyte necrosis.

Question 17

What happens if LV contractility decreases?

Answer 17

Increased LA/PV pressures which can cause pulmonary edema and increased PA/RV/RA pressures which can cause peripheral edema. Increased venous return (preload) can also occur, leading to an increase in cardiac output.

Question 18

What happens if there is a decrease in cardiac output?

Answer 18

There are two pathways that can occur:

An increase in renin/ angiotensin/ aldosterone, resulting in increased renal Na+ and H2O retention, increased contractility, and increased cardiac output.
Increased sympathetic activation, leading to an increase in renin/ angiotensin/ aldosterone, increased renal Na+ and H2O retention, increased contractility, and increased cardiac output.

Question 19

What are the potential consequences of increased LA/PV pressures?

Answer 19

Increased LA/PV pressures can cause pulmonary edema.

Question 20

What are the potential consequences of increased PA/RV/RA pressures?

Answer 20

Increased PA/RV/RA pressures can cause peripheral edema.

Question 21

How does tissue fluid exchange occur?

Answer 21

Tissue fluid exchange occurs through the interaction of hydrostatic and oncotic pressures across capillary walls. Hydrostatic pressure drives fluid out of the capillaries, while oncotic pressure draws fluid back in.

Question 22

What is oedema?

Answer 22

Oedema is the accumulation of excess fluid in the tissues.

Question 23

What is pulmonary oedema?

Answer 23

Pulmonary oedema is the accumulation of excess fluid in the lungs.

Question 24

What is ascites?

Answer 24

Ascites is the accumulation of excess fluid in the peritoneal cavity.

Question 25

What is remodelling in the context of the cardiovascular system?

Answer 25

Remodelling is the chronic response to injury in the cardiovascular system that results in changes in shape, size and function.

Question 26

What can cause remodelling in the cardiovascular system?

Answer 26

Pressure overload, volume overload, and myocardial damage (e.g. myocardial infarction, alcohol, viruses) can cause remodelling in the cardiovascular system.

Question 27

What is the result of remodelling in the cardiovascular system?

Answer 27

The result of remodelling in the cardiovascular system is hypertrophy and/or dilation, which can initially be compensatory but eventually pathological.

Question 28

What happens when the sympathetic nervous system is activated in response to low cardiac output?

Answer 28

When the sympathetic nervous system is activated in response to low cardiac output, it increases contractility and cardiac output, but can also increase afterload and cause catecholamine cardiotoxicity.