3-Temperature Regulation

Question 1

core body temp

Answer 1

maintained over range of environment temps by autoreg
-vary with time of day, estrous cycle, activity, age
-will remain constant even if extremities change

aka internal temp, skin temp is shell temp

Question 2

thermoreg balance b/t

Answer 2

heat loss- thru body/skin to environment
and heat production- metabolism

Question 3

4 modes of heat transfer

Answer 3

1. radiation
2. conductino
3. convection
4. evaporation

Question 4

radiation

Answer 4

transfer by electromagnetic rays down thermal gradient (high to low temp)

affected by clothing/color on reflection and absorption
-light colors reflect

Question 5

conduction

Answer 5

by direct contact down thermal gradient

conductivity - rate of transfer by conduction

Question 6

changes in conductivity

Answer 6

air = low
water = high
heat = vasodilate, inc conductivity
cold = vasocon, dec conduct to limit heat loss

Question 7

convection

Answer 7

loss by currents/wind down thermal gradient
-cool by wind when warmed air adj to skin quickly blown away
-loss greater in water

Question 8

evaporation

Answer 8

aka sweating/vaporizing liquid against gradient
-cholinergic sympathtic fibers to sweat glands

nervous sweating thru act of alpha-1 receptors on glands

water must evap to provide cooling

Question 9

feedback loop cycle

Answer 9

1. sensory receptors send afferent arm to CNS
2. central processing/integration
3. efferent mechanism to reduce sensory input to defend set point temp (negative feedback)

Question 10

efferent arm effector organs

Answer 10

1. brown adipose tissue
2. cutaneous circulation
3. skeletal muscle

Question 11

cascade of inc body temp

Answer 11

1. normal core temp 37 celcius
2. inc body temp from exercise or hot environment
3. activation heat receptors
4. hypothalamic activation for heat loss
5. cutaneous vasodilation
6. sweat response via symps
7. body temp reduced

Question 12

TRP receptors

Answer 12

1. cold-pain = TRPA1
2. cold-receptors = TRPM8 (menthol)
3. warm receptors = TRPV3 and 4
4. heat-pain = TRPV1 (capsaicin) and 2

overlapping sensitivity to varying temps

Question 13

responses to heat

Answer 13

1. perspiration > dehydration
2. cardiac probs > inc permeability of cardiac cells, inc HR
3. dec BP > xs cutaneous vasodilation
   4.

Question 14

cascade of dec body temp

Answer 14

1. normal core temp 37
2. dec body temp from cold environment
3. activate cold receptors
4. hypothalamic activation to heat promote
5. cutaneous vasoconstrict to dec blood supply to skin
6. skeletal muscle activation- shivering
7. body temp inc

Question 15

responses to cold

Answer 15

1. vasoconstriction - dec blood supply to extremities, inc chance of frostbite, digestive disturbance, angina pectoris (inadequate coronary flow)
2. inc metabolic heat production
3. release thyroid hormones to inc metabolism

Question 16

how fever disrupts feedback regulation

Answer 16

inflamm cytokines (pyrogens) in hypothalamus tricks brain into thinking set point is too low = activate heat generating mechs

-when treat then restore hypothalamus ability to detect inc core temp and act heat losing