Circulatory system carries oxygen and glucose in blood to all body cells so that energy can be released through respiration.
Heart pumps blood around body:
- Heart relaxes to fill with blood
- Heart contrats to release blood into arteries
When heart contract, blood put under pressure and sent to arteries. Ensures blood reaches all parts of bofy supplying cells with oxygen and glucose for respiration. Surge of blood is heart beat/pulse. Blood in arteries under constant high preassure
Blood pressure is mesure of the force of blood per unit area as it flows through arteries. Mearsures in mm Hg (millimeters of mercury).
It is represented by two measurements, e.g. 120/80 mm Hg:
- Systolic (first number) is the pressure in arteries when heart contracts- bp at highest
- Diastolic (second number) is the pressure in arteries when heart relaxes.
Normal bp is about 120/80 mm Hg, can be affected by age and lifestyle.
Can reduce high bp and maintain normal bp by doing regular aerobic exercise to strengthen heart. Healthy diet can also help by weight steady.
High bp is dangerous because blood vessels can weaken and burst, and if they burst in the brain they may cause brain damage or a stroke; or in kidneys, kidney damge. Low bp means blood doesnt circulate effciently depriving some parts of the body of glucose and oxygen. this can lead to dizziness, fainting, and cold hands and feet. Pressure in kidneys may drop causng kidney failure.
Factors that can lead to High Blood Pressure
- Excess weight.
- High stress levels.
- A diet high in saturated fat, sugar, or salt- saturated fat can lead to the build up of cholestral in rteries froming plaques which can block blood flow, increasing the risk of heart attack.
- Smoking- CO produced greatly reduces oxygen carrying capacity of blood as it takes the place of oxygen in haemoglobin. Nicotine increase heart rate.
Causes of Heart Disease
- High blood pressure
- Too much salt
- High-fat diets
High-fat diets and high cholestral can block atreries and cause heart attacks. Heart attacks are more likely with narrow coronary arteries and thrombosis.
Health and Fitness
Healthy: free from infection
Fit: how much physical activity you're capable of and how quickly you recover.
Different types of exercise develope different aspects of fitness, all measurable. Best to use combination than just one to test fitness.
Cardiovasular efficiency: how well heart copoes with aerobic exercise and how quickly it recovers- often a measure of general fitness.
Fit person's heart will return to normal quicker than an unfit person's. During exercise a fitter person will have a lower heart rate than an unfit person.