Thermoregulation Flashcards Preview

IMSK Exam 2 > Thermoregulation > Flashcards

Flashcards in Thermoregulation Deck (24):
1

When is body temperature the lowest and highest?

3-6 AM -1C
3-6 PM + .3-.5C

2

What percent of heat is lost via conduction?

3%

3

What percent of heat is lost via convection?

12%

4

What percent of heat is lost via radiation?

60%

5

What percent of heat is lost via evaporation?

25%

6

What is the heat balance equation?

(M-W) - (R+C+E) = S

7

Where is the thermoreceptor for blood located?

Hypothalamus

8

Where do peripheral receptors send signals to?

Hypothalamus

9

What systemic affects does the cold have?

Shivering, increased ventilation, increased HR, increased CO, vasoconstriction, increased BP, increased NE/T3

10

What systemic affects does heat have?

Sweating, vasodilation, increased HR, increased CO

11

How is a febrile condition induced?

Infection or pyrogen enters the body and macrophages recognize and release cytokines

12

Which cytokines come from macrophages and induce fever?

IL-1 IL-6

13

How do interleukins work?

Affecting hypothalamus and prostaglandin E2 change temperature resetting it to higher temperature

14

Why does shivering occur in febrile states?

Because your core temperature is at 37 and the hypothalamus has been set to a higher temperature so you shiver to increase body temperature

15

How do cytokines cause fever?

They cross the BBB and affect the OVLT endothelial cells to release PGE2 which affects the hypothalamus to increase the bodies normal temperature

16

At what temperature can the nervous system begin to be affected?

40C

17

What are the benefits of exercise?

Increasing the temperature by 10C increases enzyme activity 10x

18

Why does body heat increase quickly during exercise?

Because the mechanisms to get rid of excess heat are not present until the temperature gets higher

19

At rest which mechanism causes the most heat loss?

Radiation

20

In exercise which mechanism causes the most heat loss?

Evaporation

21

Why is it easier to run in cooler weather?

Because more blood can be sent to the SM instead of skin for heat loss

22

Why does heart rate increase over long periods of exercise?

Because decreased blood volume and decreased stroke output

23

At what point below normal body temperature does the body lose the ability to regulate temperature?

34.5C

24

What physiological changes occur with heat acclimization?

Blood volume increases (plasma volume)
Sweat increases
Cardiac output increases (increased SV)
Heart rate decreases
Core temperature decreases
More blood to SM not skin