Final Exam - Thermoregulation

Question 1

heat production

Answer 1

thermogenesis

Question 2

heat loss

Answer 2

thermolysis

Question 3

maintenance - thermogenesis

Answer 3

Vasoconstriction
Shivering
Piloerection
Curling up

Question 4

maintenance - thermolysis

Answer 4

vasodilation
sweating
pilorelaxation
stretching out

Question 5

Effect of shivering

Answer 5

increase metabolism –> similar to light exercise

increase heat production by 500%

Question 6

Target organs of nonshivering thermogenesis

Answer 6

brown adipose tissue (BAT) + skeletal muscle

• skeletal muscle = primary in adults
• BAT = primary in infants

Question 7

Net energy moves from ____ to _____

Answer 7

warmer object to cooler object

Question 8

Mechanisms of heat loss

Answer 8

Radiation
Evaporation
Convection
Conduction

Question 9

Latent heat of vaporization

Answer 9

Evaporization

Question 10

Most heat loss occurs d/t

Answer 10

radiation

Question 11

Radiation

Answer 11

Heat loss by transfer of photons

NOT to surrounding air

Question 12

Evaporization

Answer 12

insensible water evaporation from skin/lungs

1/2 d/t respiratory loss

Question 13

Decrease radiation heat loss by

Answer 13

incubator/barrier between patient/object

Question 14

decrease evaporation heat loss by

Answer 14

humidification, covering exposed skin, using warm preps

Question 15

conduction

Answer 15

heat loss thru contact with cooler object

Question 16

conduction requires

Answer 16

direct contact

Question 17

conduction heat loss can be minimized by

Answer 17

insulation, bair hugger, warming mattress under patient

Question 18

convection

Answer 18

heat loss thru moving cool air

Question 19

primary terminal organ for cold sensation

Answer 19

Krause’s end bulb

Question 20

Krause’s end bulb - range of stimulation

Answer 20

15-25*C

Below = only pain receptors active

Question 21

primary terminal organ for warm sensation

Answer 21

Ruffini’s Corpuscle

Question 22

Ruffinis Corpuscle - range of stimulation

Answer 22

25-45*C

Question 23

Cold sensation transmitted to spinal cord via

Answer 23

small-diameter, myelinated, A delta nerve fibers

Question 24

Warm sensation transmitted to spinal cord via

Answer 24

unmyelinated C nerve fibers

Question 25

Peripheral sensors: afferent temp

Answer 25

terminal organ –> nerve fibers –> substantia gelatinosa of posterior horn (spinal cord)
–> anterolateral spinothalmic tract to thalamus

Question 26

Central sensors: afferent temp

Answer 26

anterior hypothalamus

outside CNS: receptors in muscles + splanchnic/vagal afferents

Question 27

earliest warning of external temperature changes

Answer 27

come from peripheral temperature sensors

Question 28

central receptors take over once

Answer 28

skin temperature has reached maximum variability

Question 29

Efferent systems: involves 2 pathways

Answer 29

neurologic, endocrine

Question 30

neurologic efferent system

Answer 30

SNS regulates cutaneous blood flow/nonshivering thermogenesis via adrenergic efferents/diaphoresis (via cholinergic efferents)

Question 31

skeletal muscle shivering is stimulated by

Answer 31

direct motor response from posterior hypothalamus

Question 32

Long term efferent control of temp

Answer 32

Endocrine system

Question 33

Short term efferent control of temp

Answer 33

Neurologic control via ANS

Question 34

Endocrine control of temp

Answer 34

ACTH, GH, ADH, TSH

Question 35

Physiologic response to hyperthermia

Answer 35

inhibition of heat production, increase heat dissipation

Question 36

most important mechanism for transferring heat between core/periphery

Answer 36

cutaneous vasodilation

Question 37

major mechanism for evaporative heat loss

Answer 37

diaphoresis

*via sympathetic cholinergic fibers

Question 38

body responds to hypothermia via

Answer 38

increasing heat production, decreasing heat loss

Question 39

Body not capable of countering heat loss at what temp

Answer 39

32-33*C

Question 40

Body decrease by 1*C results in

Answer 40

6% reduction in metabolism
8% reduction in O2 consumption
7% CBF/brain O2 consumption
7% MAC reduction