GCSE Biology B1

Healthy means being free of any infection or disease.

Fit is a measure of how well you can perform physical tasks.

- Fitness is measured in different ways, it is not precise.

- Fitness profiles measure strength, speed, agility and flexibility together with stamina.

- Stamina is a good indication of cardiovascular efficiency ( the ability of the heart to supply the muscles with oxygen). It can be tested by measuring oxygen uptake during excercise and blood pressure.

Blood is being pumped around the body under pressure.

1). It is pumped bu the contractions of the heart which increase the pressure of the blood.

2). The blood leaves the heart and flows through the arteries.These split into thousands of tiny capillaries, which takes blood to every cell in the body. It then flows back to the heart in veins - the pressure is lowered.

3). Blood pressure is at its highest when the heart contracts. (Systolic Pressure) When the heart is relaxed its at its lowest (Diastolic Pressure).

4). BP is measured in mm of mecury (mmHg)

5). Healthy Person -135 over 85

Factors that increase blood pressure - Smoking, Being overweight, too much alcohol, being under a lot of stress.

If BP is too high it can cause blood vessels to burst, leads to Strokes, Brain Damage and Kidney Damage.

If BP is too low, it causes poor circulation and tissues dont get all the food and oxygen they need. Leads to fainting.

Smoking can increase BP.

Carbon Monoxide - combines with haemoglobin in red blood cells which reduces the amount of oxygen they carry.

Nicotine - increases heart rate. The heart contracts more often.

Poor diet can lead to Heart disease

If diet is high in saturated fat or salt, more at risk of developing heart diseases - build up of cholestoral:

- fatty substance

- used for making cell membranes. Too much = builds up in arterys.

- forms plaques in artery walls, narrows arteries. Restricts the flow of blood.

Salt can also causes High BP, encourages the build up of plaque which can lead to a heart attack.

Narrow Arteries incease the risk of heart attack.