Internal defenses - Fever

Question 1

What is a fever?

Answer 1

A fever is an elevated body temperature where the body’s thermostat is set at a higher point.

Question 2

What causes a fever?

Answer 2

A fever is caused by pyrogens.

Question 3

What is an example of a pyrogen?

Answer 3

Interleukin - 1

Question 4

What does interleukin - 1 do?

Answer 4

Is a pyrogen released by macrophages, dendrites and epithelial cells. It acts on the hypothalamus to induce a fever by increasing the set point.

Question 5

Describe what happens in a fever.

Answer 5

1. Macrpophae is activated and releases pyrogens.
2. Pyrogens act on the hypothalamus to increase the set point. The set point in a fever somewhat acts as the body’s optimal temperature. The set point is much high, however.
3. This causes vasoconstriction and shivering as the body temperature is still regulated by the hypothalamus and it detects a low temperature due to the high set point.
4. When the fever breaks the set point is returned to normal and the individual will feel hot and so vasodilation and sweating will occur.

Question 6

What are 3 benefits of a fever?

Answer 6

1. Inhibit the growth of some microbes
2. Inhibit replication of viruses through the release of interferons
3. Speed up chemical reactions

Question 7

What are interferons?

Answer 7

Proteins produced by cells as a defensive response to infection preventing the replication of viruses.