hypothalamus

Question 1

how does temperature affect cellular function

Answer 1

enzyme activity (CoQ10)

Question 2

what are the three locations of thermoreceptors

Answer 2

brain
viscera
cutaneous

Question 3

how do the thermoreceptors of the viscera differ from those of the brain

Answer 3

they not only detect core temperature, but also “threat” of temperature changes from hot/cold ingested food

Question 4

are there more warm or cold cutaneous thermoreceptors

Answer 4

10x more cold sensitive

Question 5

what structures in the brain hold the thermoreceptors

Answer 5

pre-optic and supraoptic regions of the hypothalamus

Question 6

are there more warm or cold hypothalamic thermoreceptors

Answer 6

3x more warm

Question 7

what thermoreceptors sense core temperature

Answer 7

visceral and brain

Question 8

what three aspects of thermoregulation are carried out in the hypothalamus

Answer 8

• determining set point (goal core temp)
• receipt of current temp info
• deciding how to adjust

Question 9

which part of the hypothalamus is responsible for responding to heat

Answer 9

anterior - heat loss

Question 10

which part of the hypothalamus is responsible for responding to cold

Answer 10

posterior - heat production

Question 11

why do babies need extra fat

Answer 11

they have a large surface area in proportion to size so they lose heat more quickly

Question 12

what two hormones are involved in heat production

Answer 12

thyroxine

epinephrine

Question 13

what structure tells you to shiver by increasing motor neuron excitation

Answer 13

dorsomedial posterior hypothalamus

Question 14

how does food intake affect body temperature

Answer 14

increased food intake => increase metabolism

Question 15

why is brown adipose tissue significant for temperature maintenence

Answer 15

it has uncoupling proteins that DECREASE the efficiency of ATP hydrolysis, resulting in MORE heat production

Question 16

what tells brown adipose tissue to increase heat production

Answer 16

sympathetic innervation

circulating epi

Question 17

what are the two types of evaporative heat loss

Answer 17

• insensible (panting like a dog)

- sweating

Question 18

what causes flushing

Answer 18

increased core temperature causes more blood to the skin for heat to dissipate

Question 19

how are sweat glands activated

Answer 19

ACh => mAChR

Question 20

what will the content of sweat be like if there is a low flow rate through the sweat glands

Answer 20

• little water

- high [Na]

Question 21

what will the content of sweat be like if there is a high flow rate through the sweat glands and why

Answer 21

• lots of water (b/c no time for water to be absorbed)

- low [Na]

Question 22

is a fever a result of failure to lose enough heat

Answer 22

NO - set point is increased b/c of infection

Question 23

what is the major player causing an increase in set point when there is infection

Answer 23

PGE2

Question 24

why do you have chills associated with fever

Answer 24

body is trying to heat up to new, increased set point

Question 25

what is responsible for the recovery period after an infection is gone

Answer 25

set point has gone down to normal and core temp needs to decrease
-apathy, anorexia