hypothalamus Flashcards
how does temperature affect cellular function
enzyme activity (CoQ10)
what are the three locations of thermoreceptors
brain
viscera
cutaneous
how do the thermoreceptors of the viscera differ from those of the brain
they not only detect core temperature, but also “threat” of temperature changes from hot/cold ingested food
are there more warm or cold cutaneous thermoreceptors
10x more cold sensitive
what structures in the brain hold the thermoreceptors
pre-optic and supraoptic regions of the hypothalamus
are there more warm or cold hypothalamic thermoreceptors
3x more warm
what thermoreceptors sense core temperature
visceral and brain
what three aspects of thermoregulation are carried out in the hypothalamus
- determining set point (goal core temp)
- receipt of current temp info
- deciding how to adjust
which part of the hypothalamus is responsible for responding to heat
anterior - heat loss
which part of the hypothalamus is responsible for responding to cold
posterior - heat production
why do babies need extra fat
they have a large surface area in proportion to size so they lose heat more quickly
what two hormones are involved in heat production
thyroxine
epinephrine
what structure tells you to shiver by increasing motor neuron excitation
dorsomedial posterior hypothalamus
how does food intake affect body temperature
increased food intake => increase metabolism
why is brown adipose tissue significant for temperature maintenence
it has uncoupling proteins that DECREASE the efficiency of ATP hydrolysis, resulting in MORE heat production
what tells brown adipose tissue to increase heat production
sympathetic innervation
circulating epi
what are the two types of evaporative heat loss
- insensible (panting like a dog)
- sweating
what causes flushing
increased core temperature causes more blood to the skin for heat to dissipate
how are sweat glands activated
ACh => mAChR
what will the content of sweat be like if there is a low flow rate through the sweat glands
- little water
- high [Na]
what will the content of sweat be like if there is a high flow rate through the sweat glands and why
- lots of water (b/c no time for water to be absorbed)
- low [Na]
is a fever a result of failure to lose enough heat
NO - set point is increased b/c of infection
what is the major player causing an increase in set point when there is infection
PGE2
why do you have chills associated with fever
body is trying to heat up to new, increased set point
what is responsible for the recovery period after an infection is gone
set point has gone down to normal and core temp needs to decrease
-apathy, anorexia
