Pathology of CVD Flashcards
Atherosclerosis
Build up of fatty material (such as cholesterol, fibrous material and calcium). Build up forms an atheroma (degeneration of walls of arteria) under endothelium (cells that line the interior surface of blood vessels).
Atheroma
Degeneration of walls of arterias
Increase of atheroma causes?
Artery loses elasticity
Blockage restricts blood flow due to decreased diameter of lumen
Restricted flow increases blood pressure
Atherosclerosis can lead too…
Various CVD such as angina, heart attack, stroke and peripheral vascular disease
Atheroma ruptures
Damage to endothelium of artery. Leads to cascade of events that form a blood clot.
Stages of blood clot
- damage to endothelium releases clotting factors
- clotting factors convert enzyme prothrombin to thrombin
- thrombin causes plasma protein fibronogen to form threads of fibrin
- fibrin threads mesh together clotting blood and sealing wound
- scar tissue forms on scaffold creating clot
blood clotting enzyme
prothrombin to thrombin
Protein in blood clot
Fibrinogen to Fibrin
Term given to formation of blood clot
Thrombosis
- blood clot (thrombus)
Thrombus breaks loose
Forms embolus which travels in bloodstream where it may end up blocking blood vessel completely
Embolus blocks a coronary artery
Can lead to heart attack (myocardial infraction) or stroke, if artery supplying brain - can cause death due to lack of oxygen
Coronary artery
Supplies heart muscle with o and glucose so can continually respire and contract
Peripheral vascular disease
Caused by narrowing of arteries that are not connected to heart or brain due to atherosclerosis
PVD often affects
Arteries in leg - pain due to lack of oxygen
Deep vein thrombosis
Blood clot that forms in a deep vein, usually in leg, can break off to form embolus and could cause pulmonary embolism
Cholesterol
type of lipid found in cell membrane, also used to synthesise sex hormones
Increased blood pressure can be caused by
diet in high saturated fats or cholesterol
Where does cholesterol come from?
produced by cells of 25% comes from liver
2 types of cholesterol carrying proteins?
HDL
LL
HDL
High density lipoproteins
Transport excess cholesterol from the rest of body to liver for elimination from body
LDL
Low density lipoproteins
Transport cholesterol from liver to rest of body and deposit cholesterol inside arteries
Cholesterol level negative feedback system
- Cells have LDL receptors on surface which allow cholestrol to be deposited inside cells by LDLs
- Once there adequate amounts of cholesterol inside cell, synthesis of LDL receptors are inhibited which reduces amount of cholesterol that is absorbed into cells
- As result, excess LDL carried cholesterol is deposited inside the arteries, lining endothelium causes atheroma to be formed
A higher ratio of HDL to LDL results in…
Lower blood cholesterol levels and reduces chances of atherosclerosis
How to raise HDL
diet of low saturated fats and regular activity can raise HDL levels
Drugs to manage cholesterol
Statins - inhibiting synthesis of cholesterol in liver
IN CHD what fatty deposits on walls of arteries called?
Plaques
Role of HDL
Transport excess cholesterol from rest of body to liver for elimination from body
