Science evision

• Disease


  A disorder that affects an organism's body, organs, tissues or cells
• Types of disease


  • Communicable
  • Non-communicable
• Communicable disease


  Can be transferred from one person to another, or from one organism to another
• Communicable diseases


  • Measles
  • Food poisoning
  • Malaria
• Non-communicable disease


  Not transferred between people or other organisms
• Non-communicable diseases


  • Cancer
  • Diabetes
  • Genetic diseases and conditions
  • Heart disease
  • Neurological disorders
• Health


  The state of physical and mental well-being
• Factors affecting physical and mental health

  • Diet
  • Lifestyle
  • Alcohol
  • Drugs
  • Stress
• Defects in the immune system

  Increase likelihood of suffering from infectious diseases
• HIV infections leading to AIDS

  Affect the immune system and lead to an increase in infectious diseases
• Viruses living in cells


  Can be the trigger for cancers
• Reaction of the immune system to pathogens and other foreign bodies


  Can trigger allergic reactions that lead to skin rashes and asthma
• Severe respiratory infections in babies

  Can lead to asthma in later childhood
• Severe physical ill health

  Can lead to depression and other types of mental illness
• Health


  The state of physical and mental well-being
• Factors affecting health

  • Work together
  • Affect physical and mental health
• Disease

  A disorder that affects an organism's body, organs, tissues or cells
• Cancer

  A disease caused by normal cells changing so that they grow and divide in an uncontrolled way. The uncontrolled growth causes a lump called a tumour to form.
• Tumour

  • A lump of cells formed as a result of uncontrolled cell division
• Types of tumour

  • Benign
  • Malignant
• Benign tumour


  • Grows slowly
  • Usually grows within a membrane, so can easily be removed
  • Does not invade other parts of the body
• Malignant tumour


  • Grows quickly
  • Invades neighbouring tissues
  • Can spread to other parts of the body in the bloodstream
  • As the tumour grows, cancer cells detach and can form secondary tumours in other parts of the body - this is called metastasis
• Cancer cells are undifferentiated - they do not carry out their normal function
• Carcinogen


  A chemical or other agent that causes cancer
• DNA


  Deoxyribonucleic acid. The material inside the nucleus of cells, carrying the genetic information of a living being.
• Mutation


  A random and spontaneous change in the structure of a gene, chromosome or number of chromosomes
• A single mutation will not cause cancer - several are required
• Risk factor


  Something that increases the likelihood of developing a disease
• Risk factors for cancer

  • Lifestyle factors (viruses, cigarette smoke, alcohol, UV radiation)
  • Industrial and environmental factors (ionising radiation, chemical carcinogens)
  • Genetic factors
• We are more likely to develop cancer as we get older
• Health


  The state of physical and mental well-being
• Factors work together and affect physical and mental health
• Disease


  A disorder that affects an organism's body, organs, tissues or cells
• Alcohol is a depressant that can be found in wines, spirits and beers
• Alcohol is also known as ethanol
• Drinking excess alcohol


  Can damage the liver, the organ responsible for processing and breaking down alcohol
• The liver can regenerate its cells
• Long-term alcohol abuse

  Causes serious damage to the liver
• Liver damage from long-term alcohol abuse


  • Patient begins by feeling sick, experiences weight loss, loss of appetite, there is a yellowing of the eyes, confusion, drowsiness and vomiting blood
  • Alcohol causes lipids to build up in the liver, leading to fatty liver disease
  • Alcohol damage leads to alcoholic hepatitis, which can lead to death
  • Cirrhosis of the liver can develop - the liver becomes scarred and loses its ability to function
• The changes to the liver from long-term alcohol abuse are now irreversible and the reduced ability to process alcohol can also lead to brain damage