Health, Infection and Response

Health

State of physical and mental wellbeing

Factors affecting Health

• Communicable and non communicable diseases

• Diet

• Stress

• Exercise

• Life situation

Types of Diseases that Interact with Health

• Defects in immune system makes you more likely to suffer from infectious diseases

• Viral infection can trigger cancers

• Immune reactions initially caused by a pathogen can trigger allergies

• Severe physical ill health can lead to depression and other mental illnesses

Cancer

• Result of changes in cells that lead to uncontrolled growth and division by mitosis

• Rapid division of abnormal cells can form a tumour

Malignant Tumours

• Cancerous

• Invade neighbouring tissues and spread to other parts of the body in the blood, forming secondary tumours

Benign Tumours

• Non cancerous

• Do not spread in the body

Risk Factors: Diet and Amount of Exercise

Risks the Non Communicable Diseases:

• Type 2 Diabetes

• Cardiovascular Disease

Effects of Diet and Amount of Exercise on Type 2 Diabetes

Body does not respond properly to the production of insulin

• Blood glucose levels cannot be controlled

Effects of Diet and Amount of Exercise on Cardiovascular Disease

Increased blood cholesterol can lead to CHD

Risk Factors: Alcohol

Risks the Non Communicable Diseases:

• Impaired Liver Function

• Impaired Brain Function

• Affected development of Unborn Babies

Effects of Alcohol on Impaired Liver Function

Long term alcohol use causes liver cirrhosis (scarring)

• Liver cannot remove toxins from the body or produce sufficient bile

Effects of Alcohol on Impaired Brain Function

Damages the brain and can cause anxiety and depression

Effects of Alcohol on Affected Development of Unborn Babies

Alcohol can pass through the placenta

• Risking miscarriages, premature births and birth defects

Risk Factor: Smoking

Risks the Non Communicable Diseases:

• Lung disease and cancers

• Affected development of unborn babies

Effects of Smoking on Lung Diseases and Cancers

Cigarettes contain carcinogens, which cause cancers

Effects of Smoking on Affected Development of Unborn Babies

Chemicals can pass through the placenta

• Risks premature births and birth defects

Risk Factor: Carcinogens (ionising radiation, genetic risk factors)

Risks the Non Communicable Disease:

• Cancer

Effects of Carcinogens on Cancer

• Tar in cigarettes and ultraviolet rays from the sun can cause cancers

• Some genetic factors makes the individual more likely to develop cancers

Treatment of Non Communicable Diseases caused by Lifestyle

• Very costly to the individual and the government

• High incidence of these risk factors can cause high rates of non communicable diseases in a population

Communicable Diseases

Caused by pathogens that can be passed from organism to organism

Pathogen

A microorganism that causes a disease

• Bacteria

• Fungi

• Viruses

• Protists

Can be spread in the air, water or by direct contact

Viruses

• Live and reproduce rapidly inside an organisms cells

• Can damage or destroy the cells

Bacteria

• Reproduce rapidly inside organisms

• May produce toxins that damage tissues and cause illness

Vectors

Organisms that spread disease by carrying pathogens

Viruses: Measles is spread by…

Inhalation of droplets that are produced by infected people sneezing or coughing

Viruses: Symptoms of Measles

• Fever

• Red skin rash

• Complications can be fatal

Viruses: Prevention and Treatment of Measles

• Painkillers

• Young children are vaccinated to immunise them against measles

Viruses: HIV is spread by…

Exchange of Bodily Fluids:

• Sexual contact

• Blood when drug users share needles

Viruses: Prevention and Treatment of HIV

• Antiretroviral drugs

  • Very damaging to the body

• Barrier methods of contraception

• Using clean needles

Viruses: Prevention and Treatment of HIV

• Antiretroviral drugs

  • Very damaging to the body

• Barrier methods of contraception

• Using clean needles

Viruses: TMV is spread by…

• Direct contact of plants with infected plant material

• Animal and plant vectors

• Soil: pathogen can remain in soil for decades

Viruses: Symptoms of TMV

• Mosaic pattern of discolouration on leaves - where chlorophyll is destroyed

  • Reduces plants ability to photosynthesise

    • Affects growth

Viruses: Prevention and Treatment of TMV

Removing infected plants

Bacteria: Salmonella is spread by…

Bacteria in or on food being ingested

Bacteria: Symptoms of Salmonella

Salmonella bacteria and the toxins they produce cause:

• Fever

• Abdominal pain

• Vomiting

• Diarrhoea

Bacteria: Prevention and Treatment of Salmonella

Poultry are vaccinated against salmonella bacteria to control spread

Bacteria: Gonorrhoea is spread by…

Direct sexual contact - STI

Bacteria: Symptoms of Gonorrhoea

• Thick yellow/green discharge

• Pain when urinating

Bacteria: Prevention and Treatment of Gonorrhoea

• Treatment with antibiotics

  • Many antibiotic resistant strains have appeared

• Barrier methods of contraception

Fungi: Rose Blackspot is spread by…

Water and wind

Fungi: Symptoms of Rose Blackspot

• Purple or black spots on leaves which turn yellow and drop early

  • Reduces plants ability to photosynthesise

    • Affects growth

Fungi: Prevention and Treatment of Rose Blackspot

• Fungicides

• Affected leaves removed and destroyed

Protists: Malaria is spread by…

Mosquitos feed on the blood of infected people and spread protist pathogen when they feed on another person

Protists: Symptoms of Malaria

• Recurrent episodes of fever

• Can be fatal

Protists: Prevention and Treatment of Malaria

• Prevent mosquito vectors breeding

• Mosquito nets to prevent bites

• Anti-malarial medicine

Controlling the Spread of Communicable Diseases: Hygiene

• Washing hands

• Disinfecting surfaces and machinery

• Keeping raw meat separate

• Covering mouth when coughing or sneezing

Controlling the Spread of Communicable Diseases: Isolation

Isolation of infected individuals - people, animals and plants to stop the spread of disease

Controlling the Spread of Communicable Diseases: Controlling Vectors

Destroying or controlling the population of the vector spreading disease can limit the spread of disease

Controlling the Spread of Communicable Diseases: Vaccination

• Protects a large number of individuals against diseases

• Cannot be used in plants because they don’t have an immune system

Vaccination

• Injecting small quantities of dead or inactive form of a pathogen into the body

• Stimulates lymphocytes to produce correct antibodies for the pathogen

• If the pathogen ever re enters the antibodies can now be produced quickly to prevent infection

Non Specific Defences: Skin

• Physical barrier to infection

• Produces anti microbial secretions

• Microorganisms that normally live on the skin prevent pathogens from growing

Non Specific Defences: Nose

• Cilia and mucus trap particles in the air, preventing them from entering the lungs

• Trachea and bronchi produce mucus, which is moved away from the lungs to the back of the throat by the cilia, where it is expelled

Non Specific Defences: Stomach

• Produces strong acid (pH2) that destroys pathogens in mucus, food and drink

White Blood Cells

• If a pathogen enters the body, the immune system tries to destroy the pathogen

• White blood cells function is to fight pathogens

• Two main types: Lymphocytes and Phagocytes

Lymphocytes: Antitoxins

• Produces antitoxins that bind to the toxins produces by some pathogen

• This neutralises the toxins

Lymphocytes: Antibodies

• Produces antibodies that target and help destroy specific pathogens by binding to antigens (proteins) on the pathogens surface

Treating Disease: Antibiotics

• Medicines that can kill bacteria in the body

• Specific bacteria needs to be treated with specific antibiotics

• Greatly reduced deaths from infectious bacterial diseases

  • But, antibiotic resistant strains are emerging

Treating Disease: Viral Diseases

• Antibiotics do not affect viral diseases

• Drugs that kill viruses often damage the bodies tissues

• Painkillers treat the symptoms of viral diseases but do not kill pathogens

Discovering and Developing New Drugs

• Drugs were traditionally extracted from plants and microorganisms

• Heart drug (digitalis) → foxglove plants

• Painkiller (aspirin) → willow trees

• Penicillin → Penicillium mould

• Most modern are now synthesised by chemists in labs

New Drugs are Tested and Trailed for…

• Toxicity - is it harmful?

• Efficacy - does it work?

• Dose - what amount is safe and effective?

Pre-Clinical Trial

Drugs are tested in cells, tissues and live animals

Clinical Trial

• Healthy volunteers received vary low doses to test whether the drug is safe and effective

• If safe, large numbers of healthy volunteers and patients receive the drug to find the optimum dose

Peer Review

• Before being published, results are tested and checked by independent researchers

Double Blind Trials

• Some clinical trials give some of their patients a placebo drug which has no effect

• Double Blind Trials → patients and doctors don’t know who has the real drug and who has the placebo

  • Reduces biases in the trial