Infection and Response

• The cancer cell can invade other tissues, spread to different parts of the body (metastasis) and form secondary tumours
• The uncontrolled growth and division of cells form a tumour (a mass of cells)
• Tumours can be benign or malignant
• Benign tumours are contained in once place (usually within a membrane) and do not spread to other parts of the body. They are not cancerous.
• Malignant tumours grow and spread to neighbouring, healthy tissues. Cells can split up and spread to other parts of the body through the bloodstream or lymphatic system. This is known as metastasis. Malignant tumours are cancerous.
• Causes of cancer include:

  1. Genetics
  2. Mutation
  3. Ionising radiation
  4. Carcinogens
  5. Virus infections
• What is a carcinogen?

  A chemical or other agent that causes cancer.
• Two main ways we can treat cancer at the moment are radiotherapy and chemotherapy.
• Non-communicable diseases - diseases that are not transferred between people or other organisms.
• Risk factors for non-communicable diseases:

  1. Diet
  2. Obesity
  3. Fitness levels
  4. Smoking
  5. Alcohol
  6. Exposure to carcinogens
• Examples of non-communicable diseases include:

  1. Cancer
  2. Diabetes
  3. Genetic diseases
  4. Heart disease
  5. Neurological disorders
• Nicotine is addictive but relatively harmless.
• People like smoking as it produces a sensation of calmness.
• Carbon monoxide is a poisonous gas found in cigarettes. After smoking a cigarette, up to 10% of the blood will be carrying carbon monoxide instead of oxygen.
• Oxygen shortage is a particular problem in pregnant women who smoke
• If the mother is carrying carbon monoxide, the foetus may not get enough oxygen to grow properly
• Lack of oxygen in a foetus can lead to:

  1. Premature births
  2. Low birthweight
  3. Stillbirths
• Tar is another toxic compound found in cigarettes
• Tar is a sticky, black chemical that accumulates in the lungs, turning them from pink to grey
• The build up of tar in the lung tissue can lead to a breakdown in the structure of the alveoli, causing chronic obstructive pulmonary disease. This reduces the surface area to volume ratio, leading to breathlessness.
• Chemicals in cigarettes also affect the heart and blood vessels
• Smoking damages the lining of the arteries. The damage encourages the build-up of fatty material in the arteries. This can lead to a heart attack or a stroke.
• The nicotine in cigarettes increase the heart rate
• What is bronchitis?


  Inflammation of the bronchi and bronchioles.
• You need some body fat to cushion you internal organs and act as an energy store but if you eat more food than you need, the excess is stored as fat and you will become obese.
• Obesity can lead to serious health problems such as type 2 diabetes, high blood pressure, and heart disease.
• The food you eat transfers energy to your muscles as they work from respiration
• People who exercise regularly have fitter hearts and bigger lungs than people who do not exercise
• Regular exercise lowers your blood cholesterol levels and reduces coronary heart disease
• Type 2 diabetes is when the body can't produce enough insulin or the body cells don't respond to insulin
• Type 2 diabetes can lead to problems with circulation, kidney function, and vision.
• Type 2 diabetes gets more common with age, but can also be caused by obesity, lack of exercise, and a diet high in simple carbohydrates
• Alcohol is commonly used as a social drug
• Alcohol is poisonous but the liver can usually remove it before permanent damage
• Alcohol increases the risk of developing a non-communicable disease
• After drinking alcohol, the ethanol is absorbed into the blood from the gut and passes easily into the body tissues
• Alcohol affects the nervous system, slowing down reaction time
• Large amount of alcohol lead to lack self-control and judgement
• Heavy drinker's may suffer long-term brain and liver damage
• Cirrhosis - scarring of the liver, which can lead to liver failure