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Extended-Response Question -Pathology of Cardiovascular Disease - Coggle…
Extended-Response Question -Pathology of Cardiovascular Disease
Blood Glucose Levels & Obesity
- type 1 & type 2 diabetes (3 marks)
Glucose Tolerance Test
Patients drink glucose solution - glucose levels are monitored
A diabetics blood glucose will increase more than a non-diabetic and will take longer to return to normal
Insulin
a hormone produced in the pancreas which regulates glucose concentrations in the blood
if blood glucose is too high the pancreas produces insulin to move the glucose from the blood into cells, where it is stored
or the liver converts it to glycogen for storage
either as body fat
Blood Glucose Regulation
Too high
liver converts glucose to glycogen
blood glucose goes down
pancreas secretes insulin
Too low
pancreas secretes glucagon
glycogen is converted to glucose
blood glucose goes up
Adrenaline stimulates the liver to break down glycogen into glucose to provide energy to respond to "fight or flight"
Thrombosis
- what it is & its effects on the body
Atherscelerosis
Build-up of fatty material underneath the endothelium (such as fibrous material, cholesterol and calcium)
This accumulation forms an atheroma
As an atheroma continues to build-up a number of things happen:
artery loses its elasticity
the restricted blood flow increases blood pressure
the blockage restricts blood flow due to the decreased diameter of the lumen
Blood Clotting
If an atheroma ruptures it can damage the endothelium of the artery, resulting with events leading to a blood clot
3.
thrombin causes the plasma proteins finbrinogen to form threads of fibrin
3.
fibrin threads mesh together clotting the blood and sealing the wound
2.
clotting factors convert the enzyme prothrombin to thrombin
5.
scar tissue forms on the scaffold creating a clot
1.
damage to endothelium releases clotting factors
Thrombosis
The term given to the formation of a blood clot (thrombus) inside a blood vessel
If a thrombus breaks lose it forms an embolus where is travels in the bloodstream where it may block a blood vessel completely
If an embolus blocks a coronary artery it may lead to a heart attack
If an embolus blocks an artery supplying the brain with oxygen it may lead to a stroke
In either case, tissue death can occur due to a lack of oxygen
Deep Vein Thrombosis
Peripheral Vascular Disease (PVD) is caused by the narrowing of arteries that are not connected to the heart nor the brain
Arteries in the legs are commonly affected by PVD
Pain in legs may be felt due to lack of oxygen reaching muscle cells
Deep Vein Thrombosis is a blood clot that forms in a deep vein, commonly in the leg
The blood clot can break off to form an embolus and can cause a pulmonary embolism
Control of Cholesterol Levels in the Body
- what it is & its effects on the body
Is a type of lipid found in the cell membrane
And it is also used to synthesise sex hormones
Too much cholesterol in the blood can cause conditions like CVD
Increased levels can be as a result of a diet in high in saturated fats, or cholesterol
All body cells produce cholesterol but 25% of it comes from the liver
There are 2 types of cholesterol carrying proteins:
HDL
high-density lipoproteins
transport excess cholesterol from the rest of the body to the liver for eliminations
LDL
low-density lipoproteins
transport excess cholesterol from the liver to the rest of the body and deposit cholesterol inside the arteries
Cholesterol levels are also controlled by negative feedback system:
1.
cells have LDL receptors on their surface which allow cholesterol to be deposited inside the cells by LDLs
2.
once there is enough cholesterol inside the cell, synthesis of new LDL receptors are inhibited which reduces the amount of cholesterol absorbed into the cells
3.
excess LDL carried cholesterol is deposited inside the arteries, lining the endothelium, causing an atheroma to form
Controlling cholesterol levels
A higher ratio of HDL to LDL will result in lower blood cholesterol levels and will reduce chances of developing atherosclerosis
A low diet in saturated fats and regular physical activity will raise HDL levels
Cholesterol can also be managed with Statins which reduce blood cholesterol levels by inhibitting cholesterol synthesis in the liver
Diabetes
Type 1
Unable to produce insulin
Treated with regular insulin injections and a careful diet
Occurs in early childhood
Type 2
Able to produce insulin
Cells have a decreased number of insulin receptors on their surface, making them less sensitive to insulin - can't convert glucose to glycogen
Treated with exercise, diet control, weight loss and in some cases insulin
Occurs in adulthood
Obesity
Term for a person with high excess body fat
At greater risk of type 2 diabetes, heart disease and some types of cancer
BMI
BMI = m/h^2
25-30 is overweight & 30+ is obese