Unit 3: Neurobiology and Immunology - Key Area 5: Non-specific Defences Flashcards Preview

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Flashcards in Unit 3: Neurobiology and Immunology - Key Area 5: Non-specific Defences Deck (27)
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1
Q

What is immunity?

A

The ability of the body to recognise and neutralise or destroy harmful foreign substances in the body.

2
Q

What are pathogens?

A

Disease causing organisms.

3
Q

What does the body defends itself against by means of immune system?

A

Disease - causing organisms (pathogens), some toxins (poisons produced by living things) and cancer cells.

4
Q

What are the 3 lines of defence of the body?

A

1) Non-specific - physical and chemical defences.
2) Non-specific - inflammatory response, phagocytosis, natural killer cells.
3) Specific - Lymphocytes, production of antibodies.

5
Q

What do non-specific defences mean?

A

They work against ANY type of disease causing agent.

6
Q

What do specific defences mean?

A

That its components each work against a particular pathogen.

7
Q

What are the cells involved in the immune system?

A

White blood cells along with others.

8
Q

What do epithelial cells do?

A

Epithelial cells form a physical barrier.

9
Q

Where are epithelial cells found?

A

In the skin and line the respiratory and digestive systems.

10
Q

What do epithelial cells provide?

A

The first line of defence against pathogens provided they remain intact as they form a protective barrier.

11
Q

Where are lysosomes produced?

A

Tears and saliva.

12
Q

What is the defensive effect of lysosomes?

A

Digest the cell walls of bacteria.

13
Q

Where is acid produced?

A

Stomach

14
Q

What is the defensive effect of acid?

A

Destroys microbes that have been swallowed.

15
Q

Where is mucus produced?

A

Mucus membranes.

16
Q

What is the defensive effect of mucus?

A

Traps microorganisms.

17
Q

Where is chemical secretions produced?

A

Sebaceous glands and sweat glands.

18
Q

What is the defensive effect of chemical secretions?

A

Keeps the pH of the skin at a level too low for most pathogens to grow.

19
Q

When the body suffers a physical injury such as a cut, what is its response?

A

The body responds with a localised defence mechanism called an inflammatory response.

20
Q

What are mast cells related to?

A

White blood cells

21
Q

What do mast cells release?

A

Histamine

22
Q

What does histamine released by mast cells do?

A

Cause vasodilation and increased capillary permeability, resulting in an increased blood flow leading to an accumulation of phagocytes and clotting elements at the site of infection.

23
Q

What are phagocytes?

A

A type of white blood cell.

24
Q

What do phagocytes do?

A

They recognise pathogens and destroy them in the process of phagocytosis.

25
Q

What does phagocytosis involve?

A

The engulfing of pathogens and their destruction by digestive enzymes contained in lysosomes.

26
Q

Following phagocytosis what do phagocytes release and what do they do?

A

They release protein molecules called cytokines which attract more phagocytes to the site of infection. Cytokines also signal to the white cells of the specific immune system to accumulate at the site of infection.

27
Q

What is the process of phagocytosis?

A

1) Phagocyte detects chemicals released by bacteria.
2) Phagocyte adheres to the bacteria.
3) Bacteria becomes engulfed in the cell membrane.
4) phagocyte forms a vacuole around the bacterium.
5) Lysosomes fuse with the vacuole and release their digestive enzymes.
6) The bacterium is destroyed by digestive enzymes.

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