B5 - Health and Disease

• Health


  • a state of complete physical, mental and social wellbeing
• Non communicable diseases 


  • diseases that can't be transmitted
  • heart/lung disease, lung cancer, obesity
• Communicable disease


  • diseases that can be transmitted
  • STI, malaria, cholera, tuberculosis
• Cholera


  • communicable
  • found bacteria found in water
  • symptoms: diarrhoea/vomiting
  • cure: have access to clean water
• Tuberculosis


  • communicable
  • transmission: bacteria coughed into air by infected
  • symptoms: coughing and lung damage
  • cure: isolate infected, good hygiene/ventilation, use PPE
• Malaria


  • communicable
  • transmission: protist with a mosquito vector
  • symptoms: damages red blood cells and liver in severe cases
  • cure: mosquito repellent and nets
• Stomach ulcers


  • communicable
  • found in bacteria in food or water
  • symptoms: stomach pain, nausea/vomiting
  • cure: clean/hygienic food, water, living conditions
• Ebola (virus)


  • communicable
  • found in bodily fluids
  • symptoms: haemorrhagic fever
  • cure: isolate infected, PPE, good hygiene
• Chalara ash dieback (fungus)


  • communicable
  • transmission: fugus carried in the air/infected trees
  • symptoms: leaf loss, bark lesions
  • cure: remove young infected trees and replant, restrict importation
• Chlamydia (bacteria)(STI)


  • communicable
  • may have no symptoms
  • can cause infertility in men/women
  • cure: wear condom, screen individuals to be treated or avoid sexual contact
• HIV (human immunodeficiency virus)


  • communicable
  • kills white blood cells which can lead to AIDS (acquired immune deficiency syndrome)
  • immune system fails
  • virus in bodily fluids
  • use condom, don't share needles,
  • mother to child - medication, screening and treatment
• Physical defences for plants


  • waxy cuticle = barrier to stop pathogens
  • cell wall made of cellulose (in case pathogen makes past cuticle)
• Physical defences for humans


  • skin (barrier to pathogens)
  • mucus trap pathogens/dirt
• Chemical defences of humans


  • hydrochloric acid in stomach kills pathogens
  • eye produce lysozyme (in tears) to kills microbes
• Chemical defences of plants 


  • poisons to deter herbivores
  • release toxins when attacked
  • excrete antibacterial chemicals (antiseptic)
• Detection of plant diseases


  • observation to detect symptoms of pathogen/environmental caused diseases
  • distribution patterns may indicate type of pathogen
  • detecting antigens using monoclonal antibodies
  • sample DNA from plants as pathogen genetic information will be present
• Immune system response

  1. antigen is identified as foreign by the body
  2. B-lymphocytes release antibodies to bind to the antigen and kill the pathogen (phagocytes also engulf pathogens)
  3. if it's the first time, memory lymphocytes are produced to the next attack the body will be ready
  4. the person is now immune and the response will be quicker
• Vaccines


  1. dead or inactive pathogen is injected into body
  2. immune response by body with memory lymphocytes
  3. so when body is actually attacked, the body responds quickly
• Monoclonal antibody production


  • antigen injected to mouse
  • mouse produced lymphocytes which produce antibodies for the antigen
  • spleen cells collected from mouse
  • fused with myeloma cells to form hybridoma cells
  • those divide to produce monoclonal antibodies
• Pros of immunisation 


  • epidemics, to a certain, degree can be prevented as herd immunity comes into play (fewer people to inject)
  • diseases such as smallpox have been wiped out cons
• Cons of immunisation 


  • doesn't always work as pathogen may always mutate
  • can have bad reaction to vaccine
  • expensive to work
• Lysogenic life cycle of a virus


  1. pathogen injects host cell with DNA
  2. pathogen remains dormant
  3. host cell continues division
  4. *enters lytic cycle*
• Lytic pathway


  1. pathogen injects DNA into host cell
  2. pathogen replicates it's DNA and protein coats
  3. assemble into new virus particles
  4. host cells undergoes lysis and bursts
  5. other cells are infected
• Non-communicable diseases

  • Cancer
  • Diabetes
  • Cardiovascular diseases
  • Chronic respiratory diseases e.g. asthma
• Risk factor


  A variable associated with a greater chance of developing a disease or infection
• Factors affecting the risk of non-communicable disease

  
  

  • Lifestyle factors - diet, exercise, alcohol, smoking
  • Environmental factors - exposure to pollution
  • Genetics - alleles that increase the risk of cancer
• "Correlation does not mean causation." Explain this statement.


  • Correlation between risk factor and disease doesn't mean risk factor causes it
• Effects of exercise on non-communicable diseases 


  
  

  • decreases fat stores
  • reducing obesity
  • decreases heart rate, recovery time and blood pressure
  • lowering the risk of CVD
• Effects of diet on non-communicable diseases

  Diet high in saturated fat

  • raises blood cholesterol levels
  • increasing the deposition of fatty deposits in the arteries

  Large amounts of simple-sugars

  • increases the risk of type 2 diabetes

  Malnourishment

  • increases the risk of deficiency diseases
• Deficiency diseases


  • Scurvy (vitamin C deficiency)
  • Anaemia (iron deficiency)
• Body Mass Index (BMI)


  A value based on height and mass used to categorise an individual as underweight, normal weight, overweight or obese
• How BMI is calculated

  BMI = mass (kg) / height^2 (m^2)
• How an individual's waist-to-hip ratio is calculated

  Waist measurement / Hip measurement
• What a waist-to-hip ratio higher than 1.0 in males or 0.85 in females indicates


  • Abdominal obesity
  • Increased risk of developing type 2 diabetes
• How alcohol affects the risk of some non-communicable diseases

  1. Alcohol broken down into toxic products in liver

  • build-up and cause cirrhosis (scarring of liver tissue)

  2. Raises blood pressure

  • increasing the risk of CVD

  3. Toxic products in alcohol can cause mutations to DNA

  • increasing the risk of cancer
• Effects of smoking on non-communicable diseases


  1. Nicotine raises heart rate

  • increasing the risk of CVD

  2. Carbon monoxide lowers the ability of red blood cells to carry oxygen

  • heart rate increases - increasing the risk of CVD

  3. Carcinogens in tar can cause mutations to DNA

  • increasing the risk of cancer

  4. Smoking increases the risk of lung diseases
• Effects of environmental factors on non-communicable diseases


  1. Long-term exposure to pollution damages the airways

  • increasing the risk of lung diseases and lung cancer

  2. Exposure to UV radiation damages DNA

  • increasing the risk of DNA mutations and skin cancer
• Effects of genetics on non-communicable diseases

  • Risks of some diseases are increased if family member has had these conditions
  • Faulty genes can be inherited which increase risk of conditions (breast cancer)
• How diseases interact with each other


  Diseases cause other infections to develop

  • HIV weakens the immune system
  • making an individual more susceptible to other infections (TB)

  Diseases reduce risk of contracting other infections

  • Trichinosis reduces development of Crohn's disease
• Effects of non-communicable disease on a local, national and global level


  Local

  • puts strain on the local hospitals
  • lack of resources, space, availability etc.

  National

  • increased pressure on NHS
  • sick related absence affects a country's economy

  Global

  • slows development