Infection and response

• What is health?


  Health is the state of physical and mental well-being.
• What is a pathogen?

  A microorganism that causes infectious disease
• Pathogens can cause communicable diseases, what is a communicable disease?

  Communicable - An infectious disease
• List 4 different types of pathogens.

  1. Virus

  2. Bacteria

  3. Fungi

  4. Protists
• Give 3 examples of viruses.

  1. Measles

  2. Rubella

  3. HIV

  
• Give an example of a disease caused by a Fungi?

  Athlete's foot

  
• Give an example of bacteria and what does bacteria look like (picture in head)?

  food poisoning (salmonella)

  
• General info about bacteria (3)

  1. very small

  2. living single-celled organisms

  3. the majority are harmless and even useful to us (e.g. in yoghurt) but some are pathogenic
• Give an example of protist?

  The pathogen that causes malaria
• How do bacteria make us ill?

  1. Divide rapidly

  2. May produce toxins that damage your tissues and affect body functions

  3. May damage cells directly
• General info about viruses (3)

  1. non-living microbes that need host cells to reproduce and survive

  2. extremely small (much smaller than bacteria)

  3. cause disease in every type of organism
• List the way diseases can spread, giver further examples of these ways.

  -Air; Colds, TB

  -Contaminated water; Cholera

  -Body fluid; AIDS, Chicken Pox, Cholera

  -Mother to unborn baby; Rubella

  -Vector;Insects or rats

  -Direct contact; Chicken pox, Athlete's foot,

  Rubella

  -Cuts/Sharing needles; AIDS, Tetanus

  -Contaminated food; food poisoning

  -Contaminated blood; AIDS
• How do viruses make us ill?

  1. take over cells in the body

  2. live and reproduce inside cells, damaging them and destroying them
• List 3 facts about protists

  1. all Eukaryotes

  2. majority are single-celled

  3. often transferred by vector
• How can we reduce the spread of diseases? (4)

  1. Simple hygiene measures; handwashing, tissues

  2. Destroying vectors; pesticides, fuming mosquitos

  3. Isolation of infected individuals

  4. Vaccination
• How are pathogens spread? Give examples (3)

  1. By air - droplet infection

  2. Direct contact

  3. By water
• How are pathogens spread by direct contact? (4) Give examples for each

  1. Animals act as vectors between infected and non-infected individual e.g. malaria

  2. STIs via direct skin contact and bodily fluids e.g. syphilis

  3. Pathogens enter body via cuts or needle punctures e.g. HIV

  4. In plants where infected material infects new crop e.g. TMV
• How are pathogens spread by air? Give 2 examples

  Droplets with pathogen released when person coughs or sneezes and another person breathes them in. e.g. coughs & colds, athlete's foot
• How are pathogens spread by water?

  Pathogens enter digestive system by:

  1. Drinking water containing sewage e.g. cholera

  2. Eating raw, undercooked or contaminated food e.g. salmonella
• Measles: symptoms, transmission, prevention and treatment


  1. Symptoms: fever, red skin rash

  2. Transmission: droplets through sneezes and coughs

  3. Prevention: vaccination

  4. Treatment: no treatment
• HIV: symptoms, transmission, prevention and treatment

  Symptoms:

  -initially flu-like illness

  -unless controlled virus attacks immune cells

  - late stage HIV/AIDS when immune system so badly damaged it cannot deal with other infections/cancers

  
  

  Transmission:

  - sexual contact

  - exchange of bodily fluids e.g. sharing needles

  
  

  Prevention:

  -contraception

  -no sex

  
  

  Treatment:

  -antiretroviral drugs
• Salmonella: symptoms, transmission, prevention and treatment

  Symptoms:

  - fever

  - abdominal cramps

  - vomiting

  - diarrhoea

  
  

  Transmission:

  - bacteria ingested in food/on food prepared in unhygienic conditions

  
  

  Prevention:

  - poultry vaccinated against Salmonella

  
  

  Treatment:

  -drink lots of fluids

  -stay comfortable

  - antibiotics (if serious)
• Gonorrhea - symptoms, transmission, prevention, treatment

  Symptoms:

  - thick yellow/green discharge from vagina/penis

  - pain on urinating

  
  

  Transmission:

  - STI; sexual contact

  
  

  Prevention:

  - barrier method of contraception

  
  

  Treatment:

  - antibiotics

  - treated easily with antiobiotic penicillin until resistant strains appeared
• Malaria: how it works, symptoms, transmission, prevention and treatment

  How it works:

  - caused by protists

  - malarial protist has a life cycle that includes the mosquito

  - affects the liver and damages red blood cells

  
  

  Symptoms:

  - recurrent episodes of fever

  - shaking when protists burst out of red blood cells

  - can be fatal

  
  

  Transmission:

  - vector; mosquito

  
  

  Prevention:

  - mosquito nets

  - preventing vectors from breeding

  
  

  Treatment:

  -antimalarial medicine
• what do vaccines contain?

  -dead pathogens

  OR

  -live but weakened pathogens

  OR

  -parts of the pathogen
• Name and describe the non-specific defence systems of the human body (4)

  1. skin - physical barrier, waterproof, anti-microbial secretions, microorganisms living on it outcompete pathogens

  2. nose - mucus + nasal hairs trap pathogens

  3. trachea + bronchi - mucus and cilia waft mucus to back of throat where it can be swallowed

  4. stomach - hydrochloric acid to kill pathogens
• How do white blood cells help defend against pathogens? (3)

  1. phagocytosis

  2. antibody production

  3. antitoxin production
• What is a lymphocyte?

  a white blood cell
• What is phagocytosis?


  White blood cells called phagocytes engulf foreign cells (pathogen) and digest them
• phagocyte


  a type of white blood cells that engulfs a pathogen and breaks it down
• What is an antigen?

  proteins produced by pathogens that are foreign to the body
• antibodies are specific to the...

  antigen
• How does vaccination work? (3)

  1. small quantities of dead/inactive forms of a pathogen introduced into body

  2. this stimulates white blood cells to produce antibodies

  3. if the same pathogen re-enters the body, white blood cells response quickly to produce the correct antibodies
• what is herd immunity?

  when a large population is immune to the disease, the spread of the pathogen is reduced a lot and the disease may disappear
• Pencillin: taken as, role, cons


  1. taken as pill, syrup, or injected

  2. role: cures bacterial diseases by killing infective bacteria inside the body, however specific bacteria should be treated by specific antibodies

  3. cons: strains of resistant bacteria emerging, cannot be used to kill viruses as these live inside cells
• Why is it difficult to develop drugs that kill viruses?

  Viruses are inside cells so it is difficult to develop drugs that won't damage the body's tissues
• What are painkillers used for?

  Treating the symptoms of disease, however they do not kill pathogens
• Traditionally where do we drugs extracted from?

  Plants and microorganisms
• Give 3 examples of drug discoveries

  1. heart drug digitalis originates from foxglove

  2. painkiller aspirin originates from willow

  3. penicillin was discovered by Alexander Fleming from the Penicillum mould
• How are most new drugs created?

  Synthesised by chemists in a pharmaceutical industry - however starting point may still be a chemical extract from a plant