these cards review the whole of the new 2011 GCSE biology B1 module.

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being fit is not the same as being healthy.

Healthy - being free of any infections or diseases.

Fitness - a measure of how well you can perform physical tasks.
fitness is measured in different ways:
strength, speed, agility, flexibility, stamina etc.

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blood pressure

Blood is pumped around the body under pressure of the hearts contractions.
contractions increase blood pressure.
blood pressure is highest when the heart contracts called Systolic pressure.
blood pressure is at its lowest when the heart relaxes called Diastolic pressure.
blood pressure is measured in mm of mercury (mmHg)

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Low blood pressure

Low blood pressure is quite uncommon.

It causes poor circulation which causes the tissues to not recieve all the food and oxygen they need. if your brain doesnt get enough food and oxygen it will make you feel dizzy and lead to fainting.

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smoking and High Blood Pressure

Smoking is a major cause of high blood pressure.
Cigarette smoke contains lots of chemicals which can increase blood pressure:

Carbon Monoxide
- combines with haemoglobin in red blood cells which reduces the amount of oxygen they can carry. this causes heart rate to increase and more contractions means higher blood pressure.

Nicotine- increases heart rate and more contractions means higher blood pressure.

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salt levels and high blood pressure

you need salt as part of a healthy diet, but eating too much can cause high blood pressure.

high blood pressure increases the risk of damage to the arteries - this damage can encourage the build up of plaques (a fatty deposit inside an artery wall) which restricts blood flow and increases the risk of a heart attack.

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Saturted fats and cholesterol

Cholesterol is a fatty substance. Too much saturated fat in a diet is linked with high cholesterol levels.
You need some Cholesterol for making cell membranes, but if you get too much it starts to build up in your arteries. this forms plaques (fatty deposits) which narrow the arteries. they restrict blood flow and can cause heart attacks.

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narrow arteries and the risk of heart attacks

The heart muscle is supplied with blood from the coronary arteries. if they become narrowed blood flow to the heart is restricted and the heart muscle recieves less oxygen. if a thrombosis (blood clot) occurs in an already narrowed artery blood flow to the heart may be cut off. the heart will be starved of oxygen. this causes a heart attack.

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Balanced diet

A ballanced diet provides you with all the essential nutrients you need:
Carbohydrate - (e.g. glucose) provide energy
Fats- provide energy, act as energy store & provide insulation
Proteins - for growth and repair of tissues and emergency energy supply
Water- to prevent dehydration.
Vitamins and minerals- various functions (e.g vitamin C prevents Scurvy)

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energy and nutritional differences for different p

A balanced diet isn't a set thing, its different for everyone.
AGE- children and teens need more protein for growth. older people need more calcium to protect against degenerative bone diseases.
GENDER- Females need to more iron to replace the iron lost in mentrual blood.
PHYSICAL ACTIVITY- active people need more protein for muscle development and crbohydrates for energy.

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Protein and diet problems

Eating too little protein can cause a condition called kwashiorkor. a common symptom is a swollen stomach. in developing countries many people have diets low in protein.
you can calculate a persons Estimated Average daily Requiremnet (EAR) of protein using the formula:   EAR (g) = 0.6 x body mass (kg)
EAR is juat an estimate though, it varies with age and changes during pregnancy. Pregnant women need extra protein to help their baby grow. women who are breast feeding need more protein to produce milk.

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Eating disorders

Some psychological disorders, e.g. anorexia nervosa and bulimia nervosa can also cause under nurtition. Anorexia nervosa leads to self starvation. bulimia involves bouts of binge eating followed by self-induced vomitting. these disorders result in poor diet which can cause a host of other illnesses e.g. liver failure, kidney failure, heart attacks, muscle wastage, etc. both disorders can be fatal.

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