Human biology. 2.7

What is Atherosclerosis?

Atherosclerosis is the accumulation of fatty material (cholesterol, fibrous tissue, calcium) beneath the endothelium, forming plaques (atheromas) that narrow and thicken the arteries, restricting blood flow and increasing blood pressure.

What is the effect of Atherosclerosis on blood pressure?

Atherosclerosis narrows the arteries, increasing resistance to blood flow. The reduced lumen size leads to higher blood pressure and reduced arterial elasticity.

What is Thrombosis?

Thrombosis is the formation of a blood clot (thrombus) in a blood vessel, often triggered by damage to the endothelium. It can obstruct blood flow and cause tissue damage.

What is the role of prothrombin and thrombin in the clotting process?

Prothrombin is converted into thrombin, which then activates fibrinogen to form fibrin threads. These fibrin threads create a mesh that stabilizes the clot.

What is an Embolus?

An embolus is a clot or other debris that breaks loose from its original site and travels through the bloodstream, potentially blocking a blood vessel and causing complications like strokes or pulmonary embolism.

What is Peripheral Vascular Disease (PVD)?

PVD is the narrowing of arteries outside the heart and brain, most commonly affecting the legs. It causes pain and cramping in the muscles due to insufficient oxygen supply.

What is Deep Vein Thrombosis (DVT), and how can it lead to a Pulmonary Embolism?

DVT is a blood clot in a deep vein, typically in the legs. If the clot breaks loose, it can travel to the lungs, causing a pulmonary embolism, which can block the pulmonary arteries.

How does Cholesterol contribute to Cardiovascular Disease (CVD)?

High levels of LDL cholesterol can accumulate in the arterial walls, forming plaques that narrow arteries, reduce blood flow, and increase blood pressure, contributing to heart disease and stroke.

What is the difference between HDL and LDL cholesterol?

HDL (high-density lipoprotein) helps remove excess cholesterol from the bloodstream, reducing the risk of atherosclerosis. LDL (low-density lipoprotein) carries cholesterol to body cells, but excess LDL can contribute to plaque buildup in arteries.

How do LDL Receptors and Negative Feedback regulate cholesterol?

LDL receptors take LDL cholesterol into cells. Once a cell has enough cholesterol, it reduces the number of LDL receptors, leading to increased LDL in the bloodstream, which can form plaques in arteries.

What is the importance of the HDL

LDL ratio in cardiovascular disease risk?

How can lifestyle changes control cholesterol levels?

Physical activity increases HDL cholesterol, and a diet low in saturated fats and cholesterol can lower total cholesterol. Replacing saturated fats with unsaturated fats also reduces the risk of cardiovascular disease.

How do statins help manage cholesterol?

Statins inhibit HMG-CoA reductase, an enzyme that produces cholesterol in the liver. This reduces blood cholesterol levels and lowers the risk of cardiovascular diseases.