lifestyle and health

Health is a state of physical, mental and social wellbeing

. Communicable diseases- are infectious and caused by pathogens such as bacteria and viruses that can be passed from one person to another

. Non-communicable diseases- cannot be transmitted from one person to another.

Both physical and mental health can be affected by a variety of factors:

. Diet- not enough nutrients can result in starvation, anemia, rickets too much bad food can result in obesity, some cancers and type 2 diabetes

. Stress- too much stress can result in heart disease, cancer and mental health problems

. Life situations- your location, gender,financial status, ethnic group, free healthcare, children, sewage and rubbish disposal

There could be a correlation between stress and depression

Illnesess interacting can make each other worse

Viruses living in cells- can trigger changes leading to cancer

If your immune system is compromised -you are more likely to suffer from communicable diseases

Immune reactions- initially caused by a pathogen can trigger allergies

Physical and mental health- are closely linked severe physical ill health can lead to mental illnesess

Malnutrition- can be linked to deficiency diseases, a weakend immune system, obesiety, cardiovascular disease, type 2 diabetes and cancer

A non-communicable disease cannot be passed from one individual to another. eg cardiovascualr disease

Risk factors- make it more likely that you'll be affected by disease, these can include but are not limited to inherited genes, age, smoking, lack of exercise, overeating, ionising radiation, UV light from the sun, second hand tobacco smoke.

Correlations between diseases and lifestyle can be seen but this does not prove that one thing is the cause of the other.

After discovering a correlation dr's and scientists do futher research to see if there is a casual mechanism. A casual mechanism explains how one factor influences another through a biological process. If a casual mechanism is demonstrated then there is a link between the two. eg smoking and lung cancer.

Everyone suffers the effects of non-communicable diseases even if they arent directly affected. They cost nations huge sums of money in research and treatment and they have the greatest effect at both human and economic levels.

Nicotine is the addictive but relatively harmless substance found in tobacco. it produces a sensation of calm and being able to cope.

Carbon Monoxide is found in tobacco smoke, this gas is poisonus and it affects the oxygen-carrying capacity of blood. After smoking 1 cigarette up to 10% of the smokers red blood cells will be carring carbon monoxide rather than oxygen.

Smoking in pregnancy can lead to shortage of oxygen resulting in premature births, low birthweights and stillbirths. 700 babies a year are born dead due to smoking.

Cilla in the trachea and bronchi that move mucus, bacteria and dirt away from the lungs are anaesthetised by chemicals in tobacco smoke, they stop working for a while and this allows dirt and pathogens into the lungs. Mucus builds up over time and this causes coughing. Tar accumulates in the lungs and it turns them from pink to grey. This makes smokers more succeptable to bronchitis and chronic obstructive pulmonary disease (COPD). COPD reduces surface area of the lungs which leads to severe breathlessness and eventually death. Tar is also a carcinogen and it greatly increases the risk of lung cancer developing, it causes other cancers such as throat, larynx and trachea.

Chemicals in tobacco smoke affect the heart and blood vessels.

Smokers are more likely to suffer from cardiovascualr disease than non-smokers.

This is a proven casual mechanism.

Smoking narrows blood vessels in skin, ageing it. Nicotine increases heart rate, whilst other chemicals damage artery lining. This makes coronary heart disease more likely and increases the risk of clot formation. Smoking increases blood pressure and the risk of heart attacks and strokes.

If you eat more food than you need the excess is stored as fat. Constant overating results in you being overweight and then obese. Obesity can lead to serious health problems such as high blood pressure and heart problems. Type 2 diabetes is another illness caused by obesity and it occurs when blood sugar levels in the body cannot be controlled properly.

The food you eat tranfers energy from respiration to your muscles. People who exercise regularly have fitter hearts and bigger lungs. 60-75% of your daily food intake is needed for the basic reactions that keep you alive. 10% is needed to digest your food. 15-30% is affected by how much exercise you do.

There are a few casual mechanisms relating to this:

More muscle tissue increasing metabolic rate, resulting in less of a chance of being over-weight. Fitter heart developing a better blood supply. Regular exercise lowers blood cholesterol.

Type 2 diabetes can lead to problems with blood circulation, kidney function, eyesight and potentially you could die. There is now overwhelming evidence suggesting that it is linked to obesity. It can be controlled by eating a balanced diet, losing weight and doing regular exercise. in extreme cases insulin supplements can be taken.

Alcohol (Ethanol) is a commonly used social drug. It is poisonus but the liver can normally remove it before it does any damage. It is very addictive.

After consuming ethanol it is absorbed into the blood from the gut and it passes easily into the body tissues, including the brain. It affects the nervous system, slowing down reactions and reflexes. In small amounts it makes people feel relaxed and cheerful but larger amounts lead to lack of self control and judgement. In some cases it can lead to unconciousness, coma and death.

Long term effects from alcohol can be expressed in the form of liver and brain damage. Cirrhosis of the liver occurs when healthy liver cells are destroyed and replaced with useless scar tissue. Because alcohol is a carcinogen sometimes people develop liver cancer. The brain can become soft and pulpy resulting in lack of function and death.

Alcohol consumption in pregnancy can result in: Miscarrige, stillbirth, premature birth and low birthweight. The baby may be born with: facial deformities, problems with its teeth, jaw or hearing; kidney, liver and or heart problems. This is known as Fetal Alcohol Syndrome (FAS)

Ionising radiation:

. Is a well known carcinogen.

. Radiation penetrates and damages the chromosones causing mutations in the DNA.

. The more exposure you have to ionising radiation the more likely you are to develop cancer.

. Breathing in radioactive materials is very dangerous as it allows the ionising radiation to penetrate directly into the cells.

. Well known sources of ionising radiation:

. Ultraviolet light from the sun- increases risk of skin cancer

. Radioactive materials- found in soil, water and air

. Medical and dental x-rays

. Accidents in nuclear power generators- Chernobyl Ukraine 1986

Leaky valves:

Over time heart valves may start to leak or become stiff and not open fully this results in breathlessness and without treatment death.

Mechanical valves are made of titanium and polymers and they last a very long time. However you have to take lifelong medication if you have a mechanical valve.

Biological valves are taken from pigs, cattle and even human donors, they work extremely well and the patient doesnt require medication but they only last 12-15 years.

In coronary heart disease the coronary arteries narrow. This is commonly caused by the buildup of fatty materials in the lining of the vessels. If blood flow is reduced so is oxygen and this results in pain, heart attack and death.

Doctors often treat coronary heart disease with a stent. A stent is a metal mesh placed in the artery, a tiny balloon is inflated to open up the blood vessel and the stent at the same time, the balloon is then deflated but the stent remains in place leaving the blood vessel open. Normal blood flow returns and the surgery can be completed without general anaesthetic.

Stents can be used to open up arteries almost anywhere in the body. Many stents also release blood thinners to prevent clots. 

Bypass surgery can also be carried out, replacing the coronary arteries with bits of veins from elsewhere in the body. This works for badly blocked arteries where a stent wouldnt work. It is an expensive surgery completed under general anaesthetic. 

Doctors are increasingly prescribing statins to anyone at risk of cardiovascular disease. They reduce blood cholestrol levels and this slows down the development of cardiovascular disease.

Heart faliure is a relatively common condition. Many people live for years with heart faliure managing the condition with different drugs.

However sometimes the heart can stop working completly and this results in someone needing a heart transplant or artificial heart.

Hearts can be transplanted by a donor, sometimes people need a heart-lung transplant. Succesful organ transplants can allow the recipient to live an almost completely normal life. 

the main problems with organ donation:

There are never enough donors and fewer potential donors fewer than about 60% of people who need a transplant get one.The antigens on the surface of the cells of the organ donor are different to those of a recipient, this may result in rejection. To reduce the risk of rejection:

Make the match between the donors and recipients organs as close as possible, treat the recipient with immunosuppressant drugs for the rest of their life, this makes organ donation more likely to be succesful. Transplants don't last forever and if the recipient becomes ill in anyway they have to take great care.

Artificial hearts:

Scientists have developed temporary artificial hearts that can support your natrual heart until it can be replaced.

They have not developed a completely artificial heart.

Artificial hearts require a lot of macheinery to keep them working

There is always a risk of blood clotting which could kill the patient

They are very expensive 

They allow the heart to rest for a few weeks/months

Your organs cannot work properly if your internal enviroment keeps changing. The balancing act of your internal enviroment is called homeostasis.

Enzymes only work at their optimum temperature and pH and they control all the functions of a cell. The functioning of individual cells is vital for the way tissues, organs, and whole organisms work. It is important for the body to be able to respond to changes in the internal or external enviroment to maintain optimum conditions for the cellular enzymes.

Internal conditions that are controlled include: Body temperature, the water content of the body and blood glucose concentration.

Homeostasis requires coordination and control. When you excercise your muscles get hotter, when you've eaten a meal your blood glucose levels rise and in hot weather you loses water and salt through sweating. Detecting changes requires automatic control systems. This includes nervous responses in your nervous systems and chemical responses in your hormone systems, they also involve many of your vital organs. 

All control systems in the body require certain key feature in order to function:

Receptors- cells that detect changes in the enviroment, these changes are called stimuli and receptors can be part of the nervous or the hormonal control systems of the body.

Coordination centres- areas that recieve and process information from the receptors.v They send out signals and coordinate the bodies response. They include the brain, the spinal cord and some major organs such as the pancreas.

Effectors- muscles or glands that bring about responses to the stimulus that has been recieved. The responses restore conditions in the body to optimum levels.

The pancreas constantly monitors and controls your blood glucose concentration using two hormones- insulin and glucagon.

Insulin- allows glucose to move from your blood into your cells. Soluble glucose gets converted into an insoluble carbohydrate called glycogen. Insulin controls the storage of glycogen in the liver and muscles. Stored glycogen can be converted back into glucose when its needed, this keeps your bllod glucose concentration stable.

Glucagon- makes the liver break down the glycogen store in your liver and convert it back in to glucose releasing glucose back into the blood. By using the two hormones the pancreas keeps blood glucose levels fairly constant. It does this using negative feedback control.

If your pancreas does not make enough (or any) insulin then your blood glucose concentration isn't controlled and you have Type 1 diabetes. Symptons include; frequent excessive urination, feeling thirsty all the time, you lack energy, you lose weight. It normally starts in childhood and the teenage years.

Type 2 diabetes occurs when your cells stop responding to the insulin you make.

Type 1 diabetes- is normally treated with insulin injections, this allows it to get straight into the blood and stops the blood glucose levels from getting too high. You can't eat too much carbohydrate and you have to plan before excercising. Insulin injections treat the disease but they do not cure it.

Doctors can perform pancreatic transplants but they are risky and expensive. There is a lack of donors and one lifelong medication is replaced with another. They are working on genetically engineering stem cells to combat the disease.

Type 2 diabetes- eat a balanced diet, lose weight, do excercise. If this doesn't work there are drugs that help insulin work better on the body cells, help the pancreas make more insulin and reduce the amount of glucose you absorb from your gut.

During puberty the reproductive hormones control the development of the secondary sexual characteristics.

The main female reprodoctive hormone is oestrogen, produced by the ovaries. Rising oestrogen levels trigger the development of the female secondary sexual characteristics. Once puberty has occured females start menstruating. Menstruation occurs every 28 days and it is a cycle. An egg starts to mature in the ovary and the uterus lining thickens this process is called ovulation. If the egg is not fertilised after 14 days the uterus lining and the egg is shed. After 35-40 years a woman goes through menopause and can no longer have any children.

Hormones involved in controlling the menstrual cycle:

Follicle stimulating hormone (FSH)- causes the egg to mature.

Luteinising hormone (LH)- stimulates the release of an egg.

Oestrogen and Progestrone- stimulate the buildup and maintenance of the uterus lining.

Male hormone is called testosterone produced by the testes

The interaction of four hormones control the maturation and release of an egg from the ovary and the build-up of the lining of the uterus in the menstual cycle.

FSH- from the pituitary gland stimulates eggs to mature in the follicles of the ovary and stimulates the ovary to produce oestrogen.

Oestrogen- secreted by the ovaries stimulates growth of the lining of the uterus and the release of LH and inhibits FSH.

LH-stimulates ovulation

Progestrone- is produced by the empty follicle after ovulation. It maintains the lining of the uterus for around 10 days and inhibits FSH and LH.

Oral contaceptives use hormones to inhibit the production and release of FSH they also stop the uterus lining from thickening. Some contraceptives only contain Progestrone but they aren't as effective as the mixed pill. The contraceptive patch is like the mixed pill except it is a patch you stick on your skin and replace every 7 days.

There are chemicals called spermicides but they do not prevent pregnancy effectively.

Barrier methods include; condoms and diaphragms. Condoms are self applied whereas diaphragms must be put in place by a doctor.

Intrauterine device (IUD)- small devices inserted by doctors, they last for 3-5 years and can be removed at anytime. Some contain copper, others contain progestone. They are very effective but could cause infections.

Abstinence- some people use the abstinence method and they abstain from intercourse during ovulation. Sometimes called the rythm method, its very unreliable.

Surgical methods- Vasectomy for men- sperm ducts are cut and tied. In women the ovaducts are cut or tied.

FSH and LH- can be used as a fertility drug to stimulate ovulation in women with low FSH levels.

In vitro fertilisation (IVF)- uses FSH and LH to stimulate the maturation of ova that are collected, fertilised, allowed to start development, and replaced in the uterus.

IVF- is emotionally and physically stressful, often unsuccsessful, very expensive and can lead to risky multiple births.