thermoregulation

Question 1

what does homeothermic mean

Answer 1

body temperature maintained in a narrow range
(35.5-37.7)

Question 2

what are the two types of heat input

Answer 2

internal external

Question 3

what are the 4 types of heat loss

Answer 3

radiant (majority)
conductive
convection
evaporation

Question 4

can body temperature vary

Answer 4

it can vary on an individual basis and over the course of the day

the daily variation can be due to physical activity, emotions, eating, environment

Question 5

where are the thermoregulatory centres of the body located

Answer 5

in the hypothalamus

Question 6

where are the thermoreceptors of the body located

Answer 6

hypothalamus and skin

Question 7

what are the mechanism used to regulate body temperature

Answer 7

sweating
change in peripheral blood flow
change in metabolic rate
hormonal regulation

Question 8

what is the pathway that cools the body when core body temperature increases

Answer 8

the hypothalamus detects the change and activates SYMPATHETIC CHOLINERGIC NEURONS which then increase sweating from sweat glands and triggers vasodilation in the cutaneous blood vessels

Question 9

what is the tonicity of sweat

Answer 9

hypotonic

Question 10

what factors can affect sweat evaporation

Answer 10

skin surface area exposed

temperature and HUMIDITY

convective currents

Question 11

what is the pathway that limits heat loss when the body detects a drop in core body temperature

Answer 11

hypothalamus detects the drop in core temperature and activates SYMPATHETIC ADRENERGIC NEURON which trigger vasoconstriction of the cutaneous blood vessels

Question 12

how does the body generate heat when it detects a drop in core body temperature

Answer 12

sympathetic adrenergic neurons increase brown fat heat production.

unregulated metabolic activity
-increases voluntary movement and metabolism

regulated metabolic activity
- shivering vs non shivering thermogenesis (skeletal muscle vs brown fat)

Question 13

how does hormonal regulation assist in thermoregulation

Answer 13

increased release of epinephrine and norepinephrine can increase heat production

prolonged cold exposure causes the thyroid gland to release more thyroxine which elevates RMR (resting metabolic rate)

Question 14

how does the body maintain thermal homeostasis during the increased stress of exercise.

Answer 14

the mechanism behind thermoregulation are the same.

Question 15

what factors affect heat tolerance

Answer 15

acclimatisation
exercise training
age
gender
body composition

Question 16

what is the difference between acclimatisation and acclimation

Answer 16

living in hot environment (acclimatisation) and simulation hot environment (acclimation).

Question 17

what are some adaptations that come with acclimatisation

Answer 17

sooner sweating
2-3 times more sweat
less NaCl lost in sweat
lower resting core temp

Question 18

how is cardiac output impacted by exercise in the heat

Answer 18

Q is elevated at lower intensities and peak Q is blunted.

SV is impaired by heat

Question 19

how is blood flow distributed during exercise in the heat

Answer 19

cutaneous blood flow will increase to facilitate cooling however the demands of the muscle take precedence.

Question 20

how does sweating impact body osmolarity

Answer 20

increases because sweat is hypotonic. this increases thirst