Thermoregulation Flashcards
What determines the temperature set-point for the body?
hypothalamus
What is the normal temperature range of the body?
36.7 C to 37.1 C
When is body temperature the lowest?
in the morning around 6 a.m.
What pattern does body temperature fluctuation follow?
circadian rhythm
What types of sensors (thermoreceptors) detect core and environmental temperature?
- cutaneous thermoreceptors
- visceral thermoreceptors
- hypothalamic thermoreceptors
Do cutaneous thermoreceptors give information about core temps or environmental temps?
environmental temperature
Though sensitive to both hot and cold, which extreme are cutaneous thermoreceptors more sensitive to?
cold
10x as many cold receptors
What kinds of temperature information do visceral thermoreceptors detect?
- core temperature
- threats to temperature maintenance
ex: eating ice cream, visceral thermoreceptors will detect the cold food and prepare the body to warm up
What regions of the hypothalamus contain thermoreceptors?
pre-optic and superoptic regions of the thalamus
Are neurons more sensitive to changes in warmth or changes in cold?
-warm sensitive
3x as many heat receptors
Does the hypothalamus lower or raise body set point temperature during sleep?
-lower
Does the hypothalamus lower or raise body set point temperature during exercise?
-raise
Which area of the hypothalamus becomes more active in response to heat and thus generates heat loss activity?
anterior hypothalamus
Which area of the hypothalamus becomes more active in response to cold and thus generates heat production behaviours?
posterior hypothalamus
What are some ways the body can lose heat?
- sweat
- larger amount of blood sent to capillaries in the skin
What are some ways the body produces heat?
- shivering
- increase in thyroxin increases metabolic rate
- increase in food consumption raises metabolism
- uncoupling of ATP (brown adipose tissue in infants)
Definition of convection.
- mvmt of molecules away from the source
eg: hot air rising
Define conduction.
- transfer of heat b/w objects in physical contact
eg: warmth in a chair after sitting
Define radiation.
- transfer of heat b/w objects NOT in physical contact
eg: the walls warm up when ppl are in the room
How is sweat produced?
- 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
What are the properties of sweat when someone is sweating at a low rate, due to only being a little bit hot?
- 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+
What are the properties of sweat when someone is sweating a lot?
-fluid is moving up the duct too quickly for water or sodium to be reabsorbed
What is meant by “acclimation” in regards to sweating?
-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
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?
- the immune system releases cytokines in response to the pathogen
- prostaglandins stimulate the body into heat production behaviours
What are physical signs that a person’s core temperature is rising during the creation of a fever?
- palor
- shivering
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?
- flushing
- sweating
