Health and Disease

• Define Health

  state of physical,mental and social wellbeing (WHO)
• Communicable diseases are caused by pathogens (virus, bacteria and fungus). These can be passed on from person to person.
• Pathogens-> Micro-organisms that causes diseases in humans and animals.
• Antibiotics work only for bacterial diseases
• Examples of Communicable diseases

  -HIV (Virus)

  -Common Cold (Virus)

  -Malaria (Protists)

  -Athletes Foot (Fungal)
• Examples for Non-Communicable


  -Cancer

  -Heart disease

  -Tuberculosis (Bacterial= can be treated with antibiotics)
• Non-communicable-> Diseases that cannot be passed from person to person.
• Define Disease


  A group of conditions that can cause lll health
• What is the role of the immune system?

  detect and destroy pathogens
• The immune system generally protects against communicable diseases
• Mental health-> encompasses emotional, psychological and social wellbeing
• Mental illness-> refers to a wide range of mental health conditions- generally disorders that affect mood, thinking and behaviour (schizophrenia, depression)
• Miccro-organisms are very small organisms, which include:

  -Bacteria

  -Fungi

  -Protists

  -Viruses
• how does hygiene reduce the spread of pathogens?

  Washing things (hands, foods) kills the pathogens on them. This stops the pathogen from spreading and infecting others
• How do vaccinations reduce the spread of pathogens?

  Vaccinations grant immunity to disease. Which makes it less likely for the person to catch/be infected and spread to others
• How does isolation reduce the spread of pathogens?

  If an infected person is isolated, they cant spread the disease as they cant come into contact with others.
• In the context of pathogens and disease, whats a vector?

  living organism that transmits pathogen from an infected organisms to another
• Example of a vector

  Mosquitos- transmits the pathogen (protist) that causes the disease, malaria
• How can pathogens enter the body?

  1. Breathed in through the mouth/nose (through the air). -e.g influenza spreads by tiny drops of saliva from a cough or sneeze
  2. Contaminated food or water- cholera spreads by water contaminated by diarrhoea of infected people and salmonella spreads when infected by salmonella and not cooked properly
  3. Through cuts or bites/ Direct contact- Athletes foot (fungal) spreads when people walk barefoot on surfaces contamindated with fungi
  4. Natural Openings
• The World Health Organisation (WHO) defines health as:

  'a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity'
• Communicable Diseases

  Communicable diseases are caused by microorganisms called pathogens which can spread between individuals or individuals and animals
• Non-Communicable Diseases

  • Non-communicable diseases are not caused by pathogens and cannot be passed on between individuals
  • Their effects on health tend to be longer-lasting; examples are asthma
  • However, the risk of developing non-communicable diseases may be increased by certain factors (including diet, stress and life situations) as these factors may have a profound effect on both physical and mental health
• balanced diet -> energy + nutrients provided = good health
• too much stress -> cardiovascular issues (high blood pressure) + poor mental health
• lifestyle + income -> standard of healthcare recieved + food bought
• the presence of having one disease makes a person be more likely to be susceptible to other diseases.

  this is because the immune system may be compromised (immune system = less effective)

  e.g. having HIV = immune system is impaired, so higher risk of other infections by bacteria, virus , fungi.

  someone with HIV, will eventually have a reduced number of lymphocytes. this reduces the ability of the immune system to fight infections
• A pathogen is any microorganism that causes disease in another organism
• Many microorganisms are pathogens including:

  • Bacteria
  • Fungi
  • Protists (protoctists)
  • Viruses
• Bacteria:

  • these are living cells that produce toxins and reproduce quickly (by binary fusion)
  • toxins damage cells
  • bacterial infections :
  • -tuberculosis
  • -bacterial menangitis
  • -cholorea
• Fungi:

  • more commonly found in plants
  • can be single celled or multi cellular
  • can produce spores + penetrate on human skin
  • on plants these are serious, as they can threaten entire crops
• Protists:

  • eukaryotic cells that spread through vectors
  • they are parasites, so it doesnt need a host to survive
• Tuberculosis: (BACTERIAL)

  • infects the lung = causes chronic cough and bloody mucus
  • associated with bad hygeine
  • airborne
• Cholrea: (BACTERIAL)

  • when bacteria infects the intestines = causes vomiting, diarrhoea and leg cramps
  • bad hygeine + water borne
• Chalara Ash Dieback: (FUNGI)

  • fungal infection
  • causes dark patched on leaves, leaf loss and bark leisons
• Malaria: (PROTISTS)

  • parasite that spreads by mosquitoes
  • causes damage to blood and liver
• HIV: (VIRAL)

  • flu-like symptoms
  • these destroy white blood cells
  • -> if untreated, compromises immune system, leading to onset of AIDS
• Helicobacter -> causes Stomach ulcers (BACTERIAL)

  • leads to stomach ulcers
• Ebola : (VIRAL)

  • infects and kills body cells
  • leads to haemorrhagic fever -> fever + internal bleeding
• Vaccination: By injecting a small amount of a harmless pathogen into an individual’s body, they can become immune to it so it will not infect them. This means they cannot pass it on to other individuals
• How are these pathogens spread:

  • cholera (bacteria) – water
  • tuberculosis (bacteria) – airborne
  • Chalara ash dieback (fungi) – airborne
  • malaria (protists) – animal vectors
  • e stomach ulcers caused by Helicobacter (bacteria) – oral transmission
  • Ebola (virus) – body fluids