Temperature Regulation Flashcards
High temps
> 106 convulsion or coma
107.6 blood damage
110 highest cellular temp compatible with life
Low temp
Q10 effect 1/2 for every 10 degree drop
Can be beneficial for brain
Organ failure before cellular damage
Body temps norm
Oral 98.6F 37C
Rectal 1 above
Ear same as oral
Axillary 1 below oral
Normal variation in temp
Circadian rhythms
Ovulation
Exercise
Core temp
Hear brain thoracic and Ab organs 100F
Shell temp
varies to maintain core temp
Radiation
i. Human body emits electromagnetic waves
ii. When wave hits surface that is cooler than body, heat is lost
iii. Body absorbs waves that are emitted from objects having a warmer surface than the body
Conduction
i. Occurs by direct contact
ii. Heat transfer moves down a thermal gradient
iii. Rate is determined by temperature difference and thermal conductivity of surface
iv. Conductivity of skin increases with vasodilation → increases blood flow
v. Vasoconstriction decreases conductivity
Evaporation
i. As water leaves the body, it takes with it a high number of calories
ii. This is due to the high specific heat of water (energy required to raise one unit of water one degree in one unit of time
iii. This takes energy from the body in the form of heat
Why water feels colder than air at same temp
Water requires more energy to change
Circulation
Temp receptors
Warm R - will increase firing w/ an increase in temp
Cold R - increase firing when temp decreases
Cold exposure
Posterior hypothalamus activated
Cutaneous & core thermoreceptor
are integrated in anterior hypothalamus compare to set point
Skin blood flow
Sympathetic control of arterioles - decrease or increase of blood flow
alpha 1 R
Sweating
Sympathetic sweat
Muscarinic
alpha 1 R nervous sweat
