Human Health and Disease

- an absence of disease

- an absence of pain

- to be fit and have good muscle tone

- an absence of stress

- also to have good mental and social health

- to have a long life expectancy

Carbs

          sugars and starch

          metabolic energy

Proteins

          metabolic energy

          needed in growth and repair and enzymes

Fats/Oils

          metabolic energy

          cell membrane formation

Vitamins

         needed in small quantities for various reactions

Minerals

          inorganic ions

          needed in small quantities for many roles

Malnutrition

          too much or too little of any food group

- too many sat fats

- fat deposits collect under the lining of the endothelium on the inside of an artery - an artheroma

- this is made from cholesterol

- dense fibrous tissue develops with it

- if the endothelial lining splits, blood comes into contact with the atheroma, which may lead to a blood clot and a blockage

- reduces blood flow, increases blood pressure

- can cause an aneurysm or an embolism

If the coronary artery is blocked, less blood and oxygen get to the heart.

This is coronary heart disease. Angina and myocardial infarction are consequences of this.

Risk factors;

- high amounts of sat fats and salt in diet
- excessive alcohol consumption
- smoking
- constant stress
- lack of excercise

Sat fats increase the levels of LDLs in the blood, which deposit cholesterol in arteries and seem to increase the resk of an atheroma

Nicotine - addictive

Tar - coat alveoli, slows down as exchange
      - coat cilia, destroys them, can't remove pollutants from the lungs

Carbon monoxide - combines with Hb, less oxygen in blood stream

Smoking related diseases;

Bronchitis - bronchi and bronchioles become inflamed, irritating fluid in lungs, coughing, increased risk of heart disease, shortness of breath

Emphysema - alveoli walls break down, less surface area, less oxygen absorbed, breathlessness, heavy breathing, 

Cancer - lung, mouth, throat, caused by carcinogens in the cigarettes

Also, blood vessel elasticity is reduced, this may lead to a heart attack

A disorder of a tissue, organ or system of an organism. Symptoms are evident. Normal bodily processes may be disrupted.

Types of disease;

Infectious, caused by pathogens. Pathogens cause disease, and can be passed from one person to another. Pathogens include bacteria, viruses, protozoa, fungi, parasites and worms.

Genetic, passed on from parent to offspring.

Dietary related diseases, caused by diet

Environmentally related, eg radiation sickness

Auto-Immune diseases, the body in some way attacks its own cells so that processes fail to function effectively

Direct contact

Droplet infection - sneezes

Via a vector - mosquito

Via food/water

Via blood transfusions/sharing needles

Caused by a bacterium via droplet infection through coughs and sneezes of sufferers. People then inhale the droplets and contract the disease.

Lesions occur on the alveoli and capillaries, inflammation occurs. This causes painful coughing. Intense coughing causes bleading. Weight loss occurs. Weak groups of people are more prone to the disease.

Prevention - mass screening using x-rays can identify scar tissue in lungs
                - sputum testing identifies the prescence of the bacteria
                - skin testing

Cure - course of antibiotics such as streptomycin 

Caused by a protozoa parasite - Plasmodium.

Carried by a vector - female mosquito - they feed off of someone who has the disease, the parasites burrow into the stomach, then move to the salivary glands, from there they pass into the mosquito's next victim

The parasite enters the blood, infecting the red blood cells, causing a fever. Symptoms include pains, exhaustion, aching, feeling cold, sweating and fever. Increased body temp. attracts more mosquitos.

Prevention - destroy the mosquitos
                - prevent them from breeding
                - introduce predators, drain ponds
                - mosquito nets

Cure - isolation, drugs 

Caused by HIV - human immune deficiency virus

Passed on by exchange of bodily fluids, transfusion of contaminated blood, or by sharing needles

HIV protein coat attahes to protein in csm of a T-lymphocyte. They fuse, release RNA and reverse transcriptase into the cell. The enzyme causes cell to produce DNA from the viral RNA. It enters the nucleus and is inorporated into the host cell chromosomes. The gene is permanently in the nucleus, and may not be activated for a long time.

Other T-lymphocytes are attacked, and cells of the lymph nodes and spleen are destroyed. The immune system becomes very weak, and can't fight of many diseases.

Prevention - screening of blood, no use of contaminated needles, protected sex