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What is a 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)
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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.
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Healthy lifestyles and risk

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.

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Disease and Data

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).

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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.
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