Temperature – decreasing or temperature – increasing mechanisms when the body temperature is either too high or too low. Fever.

Question 1

fever definition

Answer 1

= pyrexia

temporary change in body temperature

caused by inflammation or infection

deviating away from normal of 37.6°C

Question 2

mechanism of fever - steps

Answer 2

1 - initiation

2 - role of pyrogens

3 - role of hypothalamus

4 - response of hypoathalamus

Question 3

mechanism of fever - step 1

Answer 3

initiation

body detects stimulus (pyrogen)

Question 4

mechanism of fever - step 2

Answer 4

PYROGENS

exogenous
- originate from outside body
- toxins
- lipopolysaccharides
- gram- negative bacteria

exogenous pyrogens stimulates production of exogenous pyrogens

endogenous
- originate from from inside body
- cytokines (IL1/IL6)
- tumour necrosis factor

endogenous pyrogens interact with hypothalamus

Question 5

mechanism of fever - step 3

Answer 5

hypothalamus

• endogenous pyrogens activate COX enzyme
• prostaglandin E2 produced
• binds to anterior hypothalamus peptide region receptors

Question 6

mechanism of fever - step 4

Answer 6

response of hypothalamus

• increase in body temp

Question 7

fever - advantage 1

Answer 7

enhancing immune response
- enhancing phagocytic activity to effectively remove pathogen for next time

Question 8

fever - advantage 2

Answer 8

inhibiting pathogens
- high temps = killing of certain pathogens

Question 9

fever - advantage 3

Answer 9

fever reduces the iron present in the bloodstream that bacteria rely on for growth

Question 10

fever - disadvantage 1

Answer 10

hyper-pyrexia = 41.5C+ leads to seizures/ delirium/ irreversible protein damage

Question 11

fever - disadvantage 2

Answer 11

dehydration

high temp = more fluid loss by sweating = kidney damage

Question 12

fever - disadvantage 3

Answer 12

febrile seizures
- common in small children
- triggered by rapid increase in body temp