Temperature Regulation Flashcards
What does thyroid hormone do for temperature regulation?
- stimulates Na+-K+ ATPase
- increase O2 consumption
- increased metabolic rate
- increases vasodilation
two things the anterior (rostral) hypothalamus stimulates to increase heat loss
- vasodilation in skin
2. sweat
process in which energy (heat) travels through a medium or space
radiation
Leptin requires synergistic action of ______ to increase body temperature
thyroid hormone
Cytokines cause the release of ______ in the OVLT of the hypothalamus where the BBB is absent
prostaglandins
skin blood perfusion can vary between _______ mL/min
400-2500
the rate of heat loss in convection depends on the
rate of fluid movement
compensatory adjustment in _________ must be made to maintain thermal balance
thermal flux
How does excessive catecholamine increase body temperature?
stimulation of a-1 receptors in vascular smooth muscle —-> reduces blood flow to the surface of the skin (heat is trapped)
_____ hypothalamus stimulates heat dissipation (parasymp)
anterior (rostral)
You are super hot and your body has vasodilated to try to increase heat loss, but you are also hypotensive. Which one will take precedence, the heat crisis or the hypotensive crisis?
temperature control will always take precedence
the transfer of thermal energy through solid matter
conduction
Why do you shiver with a fever
peripheral vasoconstriction shuts blood supply to the skin down to increase core temperature, and this is perceived as cooling of the skin even in a warm room
What happens with heat acclimation? (5 things)
- lower heart rate
- lower threshold for cutaneous vasodilation
- better control of core temp
- increased plasma volume
- increased sweat
Why are you at more risk for heat stroke when you are dehydrated?
reduced ability to perspire
hypothermia induced impairment of temperature regulation- unable to self regulate (like shivering) temperature range
30-34 C
(86-93.2) F
Eccrine glands are innervated by the ______ and use _____
sympathetic nervous system
acetylcholine
sweating is less effective as air becomes:
saturated with water vapor
more humid!
two things the posterior (caudal) hypothalamus stimulates in relation to heat conservation
- skin vasoconstriction
2. postural changes
Cold receptors respond to a range of cool temperature _________
24-28 C
The mechanism for heat loss from the skin surface is usually a combination of:
radiation + convection + evaporation
during conditions of low physical activity, how is most of the heat lost from the body?
radiation
In the dry Phoenix air, how much sweat can be evaporated from the skin/resp. tract in an hour?
2-3 liters
rate of heat transfer between a body and moving air is __________ than the rate between a body and moving water
lower
Why is sweat rate greater in trained individuals
skin blood perfusion is greater