Topic 1 - CVD 1.5 - 1.11 Flashcards
What is CVD
Any disease that effects the heart and blood vessels
What is atherosclerosis
A process where a plaque builds up in the artery
Describe the process of atherosclerosis
-High blood pressure damages the endothelium
- Inflamatory response is triggered and white blood cells move into arterial walls
- Cholesterol builds up under the arterial wall forming an atheroma
- Ca2+ salts in the blood + fibrous tissue cause the atheroma to harden into an atherosclerotic plaque
- The hardening of a plaque causes the arterial wall to lose elastcity (reducing stretch and recoil)
-The lumen is also narrowed by the plaque
-Blood pressure increases further
What is a positive feedback loop
Where increasing one factor results in a change that increases the factor further
What is thrombosis
The process of forming a blood clot
What is the blood clotting cascade
A series of steps that must happen in a specific order to form a blood clot after injury
Why does blood clot
To prevent blood loss
Toprevent pathogens from entering the body
What are platelets
Tiny fragments of cells (with no nucleus) which are activated when blood vessels are damaged / ruptured
Specifically, the platelets must be exposed to collagen
What happens in the blood clotting cascade
The arterial wall is damaged.
Platelets stick to the ruptured site and are exposed to collagen
Platlets clumping together forms a temporary blood clot
This causes the platlets to release thromboplastin
.
In the presense of ca2+ and vitamin K, thromboplastin converts prothrombin into thrombin.
Thrombin then acts as a catalyst to convert (abundant and insoluble) fibrinogen into (soluble) fibrin.
Strands of fibrin form a mesh which trap platelets and red blood cells
This forms a blood clot.
The blood clot CAN harden to form a scab
What is Prothrombin
A soluble plasma protein used in the blood clotting cascade.
It is converted into thrombin by Thromboplastin
What is thromboplastin
A chemical found in platelets and a tissue factor
It converts prothrombin in thrombin when in the pressence of ca2+ and vitamin K
What is thrombin
A globular enzyme that acts as a catalyst
It converts thrombin to fibrinogen
What is fibrinogen
An abundant plasma protein. It is soluble and always readily available
It is converted into fibrin by thrombin
What is fibrin
An insoluble, long stranded protein.
It forms a mesh to trap platelets and RBC’s
It is made when thrombin catalyses fibrinogen into fibrin
What are coronary heart diseases (CHD)
Diseases which affect coronary circulartion and the heart
(vessels that suppy the caridac muscle with oxygen)
What is angina
The partial blockage / narrowing of coronary arteries.
It causes mild discomfort /chest pain
How does angina cause heart / chest pain
During exercises the herat requires more o2 as it contracts more
The partial blockage reduces the amount of o2 supplied to cardiac muscle
This means there is less aerobic respiration and less ATP
This means more anaeronbic respiration will occur
This means there is an increase in lactic acid produced
Lactic acid causes heart pain.
What is a stroke - (Ischemic stroke)
Sudden loss of brain function due to a blockage in arteries
-strokes can be fatal depending on where oxygen is blocked from
How does blockage in arteries cause a stroke
Less oxygen is supplide to the brain, so less aerobic respiration occurs
Anaerobic respiration increases, and more lactic acid is produced.
this decreases the pH and causes vital enzymes to denature
What is a heart attack (Myocardial infraction)
Complete blockage of coronary arteries
Caused by blood clots or atheromas
Can lead to cardiac muscle or heart failure (as the blood stops no oxygen is delivered to the cardiac muscle, and the muscle dies)
How do Heart attack occur
Cessation of blood flow (it stops)
Less / no oxygen is supplied to cardiac muscle
Aerobic respiration decreases, so ATP decreaes
The heart muscle cant contratct (its dead)
What does Ischemic mean
The stoppage / restriction of blood flow
What is an anneurysm
The swelling / buldging of blood vessels
How do anneurysms occur
When the arterial wall is damaged, elasticity is damages, so it cannot stretch to accommodate blood volume.
as the blood volume increases the artery buldges