3.9 Gastrointestinal Physiology body temp

Question 1

body temp is a compromise between?

Answer 1

metabolic heat production and heat loss to the environment

Question 2

what causes heat production?

Answer 2

1) basal metabolism
2) muscle activity
3) temperature effects on metabolism
4) hormonal effects
5) specific dynamic action of food

Question 3

radiation

Answer 3

transfer of heat from one object to another with which it is NOT in contact

Question 4

evaportaion

Answer 4

conversion of water to vapor

Question 5

conduction

Answer 5

transfer of heat from one object to another with which it is in direct contact

Question 6

convection

Answer 6

removal of warmed humidified air from the area of contact

Question 7

what is the most important mechanism of heat loss in a cool environment?

Answer 7

radiation

*accounts for 60% of heat loss from a nude body at room temp

Question 8

what is the most important mechanism of heat loss in a warm environment?

Answer 8

evaporation

*but it is inhibited by humidity

Question 9

conduction accounts for ~15% heat loss but is relatively?

Answer 9

unimportant when compared to radiation in cool enviro or evaporation in warm enviro

Question 10

convection ALONE is not particularly important, but is AIDS?

Answer 10

conduction and evaporation considerably

Question 11

what is normal body temp?

Answer 11

oral= 98.6F (1) or 37C(0.6)
rectal= 99.6F or 37.6C
core= same as rectal

Question 12

how does radiation work?

Answer 12

vasodilation of cutaneous vesels > increase blood flow > increse radiation and heat loss
*controlled by decrease sympathetic tone

Question 13

how does evaporation work? controlled by?

Answer 13

productino of sweat by eccrine glands (mostly water, some waste, some Na/K/Cl)
*controlled by sympathetic cholinergics > sweat glands > production

Question 14

how does heat conservation work?

Answer 14

1) vasoconstriction of cutaneous vessels
2) decrease sweat gland activity
3) behavioral (avoidance) mechanisms to decrease surface area

Question 15

how does heat production work?

Answer 15

Muscle activity

1) voluntary =conscious
2) muscle tone and contraction =semiconscious
3) shivering; oscillation of stretch reflex = involuntary

Question 16

heat production hormones

Answer 16

1) epinaphrine
2) norepinephrine
3) thyroxine
4) sex hormoens

Question 17

what are the 2 temp sensitive receptors?

Answer 17

peripheral and central

Question 18

peripheral thermoreceptor

Answer 18

skins= tells what environment is like

Question 19

central thermoreceptor

Answer 19

brain and spinal cord

Question 20

temp regulating complexes located in?

Answer 20

hypothalamus

Question 21

define “set point”

Answer 21

like a thermostat= critical core body temp; normally 99.6F for core
*WHAT THE HYPOTHALAMUS WANTS TO MAINTAIN

Question 22

what happens when temp rises above set point?

Answer 22

heat loss mechanisms activated and heat production and conservation mech. are inhibited

Question 23

what happens when temp falls below set point?

Answer 23

heat production and conservation mech. activated and heat loss mech inhibited

Question 24

thermal signals from the skin?

Answer 24

alter the set point (changes relationship between core temp and set point)

Question 25

when cold receptors are stimulated in skin

Answer 25

= increase set point slightly > heat production and conservation mech. are stimulated

Question 26

when heat receptors are stimulated in skin

Answer 26

= decrease set point slightly > heat loss mech. are stimulated

Question 27

peripheral signals initiate corrective measures before?

Answer 27

core temp changes

Question 28

define fever

Answer 28

an elevation of body temp caused by a resetting of the hypothalamic thermostat

• body temp regulation still occurs, but at a higher set point
• caused by infection, trauma, or stress

Question 29

what causes fever?

Answer 29

endogenous pyrogens

Question 30

prostaglandins released by?

Answer 30

hypothalamus

Question 31

fevor mechanism

Answer 31

1) endogenous pyrogens (interleukin 1 and 6) are released from macrophages inthe presenc of bacteria or other fever-producing stimuli
2) hypothalamis prostaglandin released
3) + thermoreceptors of hypothalamus raise set point

Question 32

how many phases of fevor?

Answer 32

3. early, steady and recovery

Question 33

early phase of fever

Answer 33

shivering, chills, increase muscle tone = raises temp

Question 34

steady phase of fever

Answer 34

core temp has reached new set point and elevated temp is sustained

Question 35

recovery phase of fever

Answer 35

sweating and vasodilation occur bc body’s mechanisms for lowering body temp are now in play
(sweating, flushed)

Question 36

temperature at which neuronal damage occurs depends on?

Answer 36

length of time temp is elevated

• 106F rectal for a prolonged period
• 108-110F for brief period

Question 37

what are artificial methods for lowering body temp

Answer 37

• aspirin and Tylenol inhibit prostaglandin release

* cool bath conduct heat to water (NOT cold- don’t want to set off conservation mech)

Question 38

typic means?

Answer 38

cool

Question 39

aspirin is bad to give children bc?

Answer 39

increased chance of viral infection