U2 KA7 - The Pathology Of Cardiovascular Disease Flashcards
What is Atherosclerosis?
The formation of plaques called an atheroma beneath the inner lining of the wall of an artery is known as Atherosclerosis
Describe the Process of Atherosclerosis
- Endothelium becomes damaged due to high blood pressure/cigarette toxins.
- Fatty deposits (mainly cholesterol), fibrous material and calcium form an atheroma/plaque in the endothelium.
- Plaque causes narrowing of arteries. (reduce diameter of lumen) and Artery thickens and loses its elasticity.
- Difficult for blood to pump – rise in blood pressure.
- Plaque leads to high blood pressure which leads to more plaque.
- Oxygen and nutrients can’t get to cells.
Consequences of the atheroma
This conditioning can then lead to various cardiovascular diseases
*Myocardial infarction
*Coronary heart disease
*Stroke
What is a Thrombus?
The formation of a blood clot (thrombus) is referred to as thrombosis.
Describe the Formation of a Thrombus
- Atheroma may rupture.
- Clotting factors released.
- The enzyme prothrombin is converted to its active form thrombin.
- Thrombin promotes fibrinogen to form threads of fibrin.
- Fibrin threads form a meshwork that clots the blood ands seals the wound forming a thrombus
What is an Embolus?
If a thrombus breaks loose it becomes known as a embolus
What are som of the consequences of an Embolus
As this occurs in arteries, the embolus may be carried along in circulation until it blocks narrower vessels
This results in blood flow being severely restricted or stopped
If this occurs in the coronary artery of the heart, it results in coronary thrombosis. The heart muscle is deprived of oxygen and may lead to a myocardial infraction (heart attack)
A blockage of arteries supplying brain leads to stroke. The brain cells supplied by that artery may die as they are deprived of oxygen.
What are Peripheral arteries
Arteries in the body that are not the aorta , coronary and carotid arteries
What does atherosclerosis/embolisms in the peripheral arteries cause?
If these peripheral arteries are affected by atherosclerosis, their central cavity becomes narrower
This can lead to a peripheral vascular disease, which most commonly affects the leg arteries.
Blood flow becomes restricted to these arteries and pain is felt in the leg muscles as the cells are receiving insufficient oxygen
Describe DVT
A deep vein thrombosis (DVT) is a thrombus that forms in a deep vein most commonly in the leg.
This causes a painful swelling in the leg and veins towards the surface of the skin become engorged with blood
Describe Pulmonary embolism
If a blood clot (embolus) travels to the lung it results in a pulmonary embolism.
Where in the body is cholesterol found?
Cell membrane
What is the role of Cholesterol
It is an important substance as a precursor for the production of steroids, such as sex hormones.
How is cholesterol removed from the body
In Bile
What is the function of Lipoproteins and where are they found?
They are found in blood plasma and are responsible for transporting lipids (including cholesterol) form one part of the body to another
What are the two types of Lipoproteins
*Low-density lipoproteins (LDL)
*High-density lipoproteins (HDL)
Where does LDL transport Cholesterol to and how does it transport it?
To body cells from Liver
When LDL carries cholesterol (LDL-cholesterol) to cells it becomes attached to a receptor. The cell engulfs the LDL-cholesterol and then the cholesterol is used by cell.
Describe negative feedback in terms of LDL and the consequences of a lack of LDL receptors
Once body cells have enough cholesterol, a negative feedback system is triggered which inhibits the synthesis of new LDL receptors.
Fewer cholesterol receptors means that less cholesterol is absorbed by body cells and is instead, absorbed into the endothelium lining of arteries.
The deposition of cholesterol in the wall of the artery forms an atheroma, potentially leading to atherosclerosis
Atheroma’s are more likely to develop in someone who
*Eats a diet rich in saturated fat throughput their life
*Suffers from a genetic condition known as hypercholesterolemia
Treatments for High Cholesterol
*Modification of diet- reducing saturated fats.
*Medication – statins.
Where does HDL transport Cholesterol to and why?
** From body cells** to liver to be broken down. ‘Good Cholesterol’
This prevents high level of cholesterol accumulating in the blood stream and HDLs do not contribute to atherosclerosis.
