Health

Metabolism = energy needed to fuel chemical reactions in the body 

Metabolic Rate = the speed at which the chemical reactions take place

E.g. the more muscle, the higher the metabolic rate because more energy is needed

More energy needed when exercising so the metabolic rate increases

Temperature affects the metabolic rate, the colder it is the higher the rate

Developed countries = higher obesity rates

Obesity problems:

• Diabetes
• Arthritis 
• Heart Disease
• High Blood Pressure

Developing countries = higher malnutrition and starvation rates

Malnutrition and Starvation Problems:

• Slow growth
• Fatigue
• Poor Resistance to disease/infection
• Irregular periods 

High cholesterol is a risk factor for heart attacks

• Blood vessels can get clogged with fatty cholesterol deposits, this reduces blood flow to the heart <-- lead to angina or heart attack
• The liver controls the amount of cholesterol in the body
• The amount it makes depends on your diet

Cholesterol is transported round the body in the blood by lipoproteins (fat attached to proteins)

• Low density Lipoproteins (LDL) carry cholesterol from the liver to the body cells <-- any excess can build up in the arteries
• High Density Lipoproteins (HDL) carry cholesterol that isn't needed from the body cells to the liver for removal

Saturated Fats - raise cholesterol in the blood, Increase amount liver makes and decreases amount it gets rid of 
Polyunsaturated Fats - lower blood cholesterol by increasing its removal from body and improving the HDL/LDL balance
Monounsaturated Fats - same as polyunsaturated fats

Eating too much salt causes high blood pressure (hypertension). 30%  of the UK population are 'salt sensitive'.

Heroin, cocaine <-- v. addictive
Nicotine & caffeine <--  fairly addictive

Testing Procedure:

• Computer models <-- stimulate a humans response
• Tested on human tissue in a lab
• Develop and test the drug using live animals
• Tested on humans in clinical trials <-- determines any side effects

Thalidomide 1950s

• Intended as a sleeping pill but was found to effective in relieving morning sickness
• Hadn't been tested as a drug for this though and it affected the fetus causing stunted growth or no growth of fetus' arms and legs
• 10,000 babies affected, only half survived 
• Banned but has been re-introduced as a treatment for leprosy & AIDs 

Tobacco

• Tobacco smoke contains carbon monoxide which combines with haemoglobin in blood cells meaning they can carry less oxygen (baby born underweight)
• Also contains carcinogens (chemicals that can cause cancer)
• Smoking also causes disease of the heart & blood vessels and damage to the lungs 
• The tar in the ciggies damages the cilia in your lungs & windpipe <-- harder for the body to eject stuff that shouldn't be there <-- makes chest infections more likely
• Nicotine in the tobacco smoke is addictive

Alcohol

• Alcohol reduces the activity of the nervous system (slows reactions down)
• Alcohol in excess causes dehydration --> damage brain cells and severe damage to the liver