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Flashcards in Immune system Deck (94)
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1

What is a communicable disease?

Diseases caused by foreign organisms invading the body and multiplying there. They can be transmitted from one person to another.

2

What is a pathogen?

Disease causing organisms

3

Contagious communicable diseases

Passed on by direct contact with a person suffering from the disease

4

Vectors

spread the disease from person to person trough intermediate hosts of the pathogen, such as mosquitos or fleas

5

Types of pathogens

- Bacteria
- Viruses
- Fungi
- Animal parasites

6

What are bacteria?

- Many are non-pathogenic and harmless to humans
- Consists of a single cell
- Cell shape is used to clarify bacteria

7

Examples of bacteria

- Chlamydia
- Meningitis (bacterial)
- Tetanus
- Whooping cough

8

What are viruses?

- Molecule of DNA or RNA surrounded by a coat of protein
- When a virus infects a living cell, the DNA or RNA induces the cell to manufacture more virus particles
- The new virus particles leave the host cell to infect other cells

9

What are bacteriophages?

Viruses that multiply in bacterial cells, causing death of the bacterium

10

Examples of viruses

- HIV/AIDS
- Chicken pox
- Colds

11

Examples of fungi

- Ring worms
- Thrush
- Tinea

12

Examples of animal parasites?

- Tape worms
- Thrush
- Ticks

13

6 ways pathogens can be transmitted?

- Transmissions by contact
- Transfer of body fluids
- Infection by droplets
- Ingestion
- Airborne transmission
- Transmission by vectors

14

Transmission by contact

- Through direct (touching an infected person) or indirect means (toughing an object that has been touched by an infected person)

15

Transfer of body fluids

- Such as blood, semen, or breast milk
- HIV, hepatitis B and C are spread this way

16

Infection by droplets

- Emitted when breathing, sneezing or coughing
- Spreads diseases such as measles, mumps, colds and influenza

17

Airborne transmission

- Can cause infection when inhaled

18

Transmission by vectors

- Transfer of pathogens by other animals, such as insects, ticks or mice

19

What are non-specific defences?

Work against all pathogens

20

What are specific defences?

Directed at particular pathogens

21

What is the purpose of the first line of defence?

- Prevents pathogens from entering and multiplying inside the body

22

The skin

- Provides a tough impervious barrier
- Oily secretions called sebum (produced in the oil glands) contain substances that kill some pathogenic bacteria
- Sweat also contains salts and fatty acids that prevent the growth of many micro-organisms

23

Mucous membranes

- Line body cavities that open to the exterior
- Secrete mucous which inhibit the entry of micro-organisms to organs of the body
- EG. in the digestive, urinary and reproductive tracts

24

Hairs and cilia

- EG. nose cavity and ears
- Trap microbes
- The beating of the cilia moves mucous containing trapped particles and micro-organisms towards the throat
- It is then coughed up or swallowed

25

Acids

- Gastric juices and vaginal secretions are acidic
- Inhibit or destroy microbes
- Sweat is slightly acidic

26

Lysozyme

- An enzyme that kills bacteria
- It is in our tears, saliva, sweat and nose secretions
- Our eyes are protected by the flushing actions of our tears, which contains this enzyme

27

Cerumen

- Traps microbes and debris
- Slightly acidic and contains lysozyme

28

Flushing action

- Urine flows from the urethra
- Has a cleansing action
- Flushes microbes out of the body
- Prevents bacteria growth and helps to stop bacteria from reaching the bladder and kidneys
- Tears, sweat and saliva are also involved in flushing out microbes

29

Protective reflexes

helps to protect the body from injury or infection
1. Sneezing
2. Coughing
3. Vomiting
4. Diarrhoea

30

Second line of defence

Non-specific and occurs if a pathogen gets past our external defences