Thermoregulation

Question 1

What determines the temperature set-point for the body?

Answer 1

hypothalamus

Question 2

What is the normal temperature range of the body?

Answer 2

36.7 C to 37.1 C

Question 3

When is body temperature the lowest?

Answer 3

in the morning around 6 a.m.

Question 4

What pattern does body temperature fluctuation follow?

Answer 4

circadian rhythm

Question 5

What types of sensors (thermoreceptors) detect core and environmental temperature?

Answer 5

• cutaneous thermoreceptors
• visceral thermoreceptors
• hypothalamic thermoreceptors

Question 6

Do cutaneous thermoreceptors give information about core temps or environmental temps?

Answer 6

environmental temperature

Question 7

Though sensitive to both hot and cold, which extreme are cutaneous thermoreceptors more sensitive to?

Answer 7

cold

10x as many cold receptors

Question 8

What kinds of temperature information do visceral thermoreceptors detect?

Answer 8

• core temperature
• threats to temperature maintenance

ex: eating ice cream, visceral thermoreceptors will detect the cold food and prepare the body to warm up

Question 9

What regions of the hypothalamus contain thermoreceptors?

Answer 9

pre-optic and superoptic regions of the thalamus

Question 10

Are neurons more sensitive to changes in warmth or changes in cold?

Answer 10

-warm sensitive

3x as many heat receptors

Question 11

Does the hypothalamus lower or raise body set point temperature during sleep?

Answer 11

-lower

Question 12

Does the hypothalamus lower or raise body set point temperature during exercise?

Answer 12

-raise

Question 13

Which area of the hypothalamus becomes more active in response to heat and thus generates heat loss activity?

Answer 13

anterior hypothalamus

Question 14

Which area of the hypothalamus becomes more active in response to cold and thus generates heat production behaviours?

Answer 14

posterior hypothalamus

Question 15

What are some ways the body can lose heat?

Answer 15

• sweat

- larger amount of blood sent to capillaries in the skin

Question 16

What are some ways the body produces heat?

Answer 16

• shivering
• increase in thyroxin increases metabolic rate
• increase in food consumption raises metabolism
• uncoupling of ATP (brown adipose tissue in infants)

Question 17

Definition of convection.

Answer 17

• mvmt of molecules away from the source

eg: hot air rising

Question 18

Define conduction.

Answer 18

• transfer of heat b/w objects in physical contact

eg: warmth in a chair after sitting

Question 19

Define radiation.

Answer 19

• transfer of heat b/w objects NOT in physical contact

eg: the walls warm up when ppl are in the room

Question 20

How is sweat produced?

Answer 20

• coiled region at base of sweat gland filters serum from nearby blood vessels (plasma, ions, etc.)
• fluid travels to surface of skin as water and Na+ are absorbed along the duct to control amt of sweating

Question 21

What are the properties of sweat when someone is sweating at a low rate, due to only being a little bit hot?

Answer 21

• lots of water has been reabsorbed
• sodium has been reabsorbed in a smaller proportion

-sweat at a low rate of flow has a relatively high concentration of Na+

Question 22

What are the properties of sweat when someone is sweating a lot?

Answer 22

-fluid is moving up the duct too quickly for water or sodium to be reabsorbed

Question 23

What is meant by “acclimation” in regards to sweating?

Answer 23

-after a while of exposure to situations in which a person sweats a lot, the body can’t tolerate the cnt’d loss of Na+, thus aldosterone ensures that Na+ is reabsorbed while still allowing the release of water in sweat

Question 24

How does the body create a fever to raise the core temperature up to the new set-point directed by the hypothalamus in response to a pathogen?

Answer 24

• the immune system releases cytokines in response to the pathogen
• prostaglandins stimulate the body into heat production behaviours

Question 25

What are physical signs that a person’s core temperature is rising during the creation of a fever?

Answer 25

• palor

- shivering

Question 26

What are physical signs that a person’s core temperature is lowering back down to the normal set-point directed by the hypothalamus after the pathogen has been eliminated?

Answer 26

• flushing

- sweating