OCR AS Biology- Heart Disease

Complete set of notes for OCR AS Biology on Heart Disease and Cholestrol.

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  • Created on: 25-03-13 21:50
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BiologyAsLevelNotes
CMW
DietandCoronaryHeartDisease
Obesity can cause: cancer, cardiovascular disease and type 2 diabetes
Also been linked to: gallstones, osteoarthritis and hypertension (high blood pressure)
Coronary Heart Disease is the result of the deposition of fatty substances in the walls of
the coronary arteries (atherosclerosis.) Dietary Fibre, oily fish and moderate alcohol
consumption help reduce the risk of CHD.
Salt: decrease water potential of the blood, resulting in hypertension (which can damage
inner lining of the arteries, resulting in atherosclerosis.)
Fats: Saturated Fats such as animal fats are more harmful than unsaturated fats such as
plant fats. Polyunsaturated and monounsaturated fats are particularly beneficial to health.
Cholesterol: Similar properties to a triglyceride. Made from saturated fats in the liver and
found in meat, egg and dairy products. High blood cholesterol will increase risk of CHD.
Cholesterol level should be kept under 5.2 mmol dm-3.
Why is cholesterol in the blood?
It is essential to bodily functions. It is found in cell membranes and in the skin. It is used to
make steroid sex hormones and bile. It is not soluble in water, so is transported around the
body in the blood in the form of lipoproteins.
High density Lipoprotein: combination of unsaturated Fats, Cholesterol and Protein. Tend
to carry cholesterol from the body tissues back to the liver. Liver cells have receptor sites
that allow HDL's to bind to their cell surface membranes. It is then used in cell metabolism
and to make bile. They remove blood cholesterol, thus reducing fats in artery walls and the
risk of atherosclerosis.
Low density Lipoprotein: combination of saturated fats, cholesterol and protein. These
tend to carry cholesterol from liver to tissues. Tissue cells have receptor sites that allow
LDL's to bind to their cell surface membranes. The more saturated fat / cholesterol
consumed, the more LDL's present. High concentration of these in the blood causes
deposition in artery walls, Saturated fats decrease activity of LDL receptors, so less is
removed from the blood. Polyunsaturated and monounsaturated fats increase LDL
receptor activity so decrease LDL concentration in blood.

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