Response to infection: Other terms/questions

Question 1

What is a phagocyte?

Answer 1

A cell that is able to break down any foreign matter and cell debris.

Question 2

What is a monocyte?

Answer 2

The largest type of white blood cells that give rise to macrophages.

Question 3

What is a macrophage?

Answer 3

A cell derived from a monocyte that is capable of engulfing foreign matter and destroying cell debris and microorganisms.

Question 4

What is a lymphocyte?

Answer 4

A non-phagocytic white blood cell that produces antibodies.

Question 5

What is an interferon?

Answer 5

Interferons are substances released by host cells in times of infection. They signal to surrounding cells to heighten their anti-viral defences, espicially during a fever.

Question 6

T-cells vs. B-cells (sites of maturation)

Answer 6

T-cells -> thymus

B-cells -> bone marrow

Question 7

Functions of antibodies

Answer 7

• inactivating foreign enzymes/bacterial toxins;
• binding to the surface of viruses and preventing them from entering into cells;
• coating bacteria to make them more easily consumable by phagocytes;
• causing agglutination; and
• reacting with solubles to render them insoluble.

Question 8

Identify the four types of vaccines.

Answer 8

1. dead/inactivated vaccines - contain dead microorganisms to stimulate the production of antibodies. This produces a weak response.
2. live/attenuated vaccines - use less virulent microorganisms incapable of producing proper disease. This produces a stronger and long-lasting response, but also an uncertain one.
3. toxoid vaccines - use toxin filtrates of bacterial cultures to encourage the production of antibodies.
4. sub-unit vaccines - utilise fragments of microorganisms to provoke an immune response.

Question 9

Functions of antibiotics

Answer 9

1. inhibit cell wall synthesis/growth;
2. inhibit a pathogen’s attachment to/recognition of a host;
3. inhibit DNA and RNA synthesis;
4. inhibit the general metabolic pathway; and
5. inhibit protein synthesis.

Question 10

Bactericidal vs. bacteriostatic antibiotics

Answer 10

Bactericidal - kill bacteria through changing the structure of the cell wall/membrane or by disrupting the functioning of essential enzymes.

Bacteriostatic - prevention of bacterial reproduction and disruption of protein synthesis.

Question 11

How can bacteria become resistant to antibiotics?

Answer 11

1. they can mutate;
2. they can develop an antibody-neutralising ability;
3. some can pump the antibiotic out of their system; and
4. some can even alter the antibiotic attack site, further reducing the strength of the antibiotic.

Question 12

How does the skin function as an external defence?

Answer 12

• protective barrier.
• heavily populated with bacteria already.
• tough, hard, and impermeable to pathogens.
• sebaceous glands secrete sebum which has anti-bacterial properties.
• contains salts and fatty acids which prevent the growth of many microorganisms.

Question 13

What is inflammation?

Answer 13

• A non-specific defence which responds to any damage to tissues by microorganisms.
• It tries to neutralise and destroy any harmful agents at the site of injury.
• Reduces spread of pathogens, destroys them, prevents entry of other pathogens, removes damaged tissue/cell debris, and begins repairing damaged tissue.
• Characterised by SHRP.