disease

What is a disease?

A disease is any malfunction of the body or mind which has an adverse effect on good health. It can produce symptoms effecting both physical and mental.

Types of disease:

• Infectious (eg common cold)
• Deficiency (eg scurvy)
• Genetic (eg huntington's disease)
• Occupational (eg cancer)
• Degenerative (eg alziehmers)
• Self-Inflicted (eg anorexia)
• Mental (eg schizophrenia)

What are pathogens?

Pathogens are micro-organisms which cause disease within the body. They can enter the body through a number of ways:

• Through a surface, for example, skin. Usually through cuts/bites, as the skin is broken and therefore less thick/ continuous.
• Though more usually through the digestive system, for example cholera...
• Or through gas exchange, for example, influenza and bronchitis.

How do pathogens cause disease?

• By damaging host tissues; sometimes lots of pathogens cause damage, for example, by stopping a tissue working properly. Viruses may inhibit the cell's mechanisms.
• By producing toxins; most pathogens produce toxins which in turn produce the symptoms of the disease.

What is a healthy lifestyle?

A healthy lifestyle is one which lowers the risk of getting diseases.

What makes a healthy lifestyle?

• Maintaining a healthy weight
• Taking regular exercise
• Eating a healthy diet
• Not smoking
• Limiting alcohol intake.

What is risk?

Risk depends on; The probability that a hazardous event will occur and the consequence of that event.

Unifactorial and multifactorial diseases

• Unifactorial: Some diseases have only one cause and may effect a certain organ or tissue (eg malaria)
• Multifactorial: Some diseases have several causes, usually depending on lifestyle (eg lung cancer)

Epidemiological studies

Epidemiological studies look at the incidence and pattern of a disease in order to find ways of prevention and cure. They look to see if a disease is ENDEMIC (naturally occuring in an area), EPEDEMIC (a disease in a small, certain area) or PANDEMIC (a disease spread across a large area, such as worldwide).

What is cancer?

Cancer is the result of uncontrolled cell division through mitosis, which forms dangerous growths called tumours, which invade surrounding tissue.

Factors which increase the risk of cancer:

• Smoking; the main cause of mouth, throart and lung cancer.
• Excessive exposure to sunlight; the main cause of skin cancer. Sunbathing without sunscreen and using sunbeds increases the risk.
• Excessive alcohol intake; can increase the risk of many types of cancer, especially liver cancer.