Week 5: Thermoregulatory systems

Question 1

What is our internal (core) body temperature?

Answer 1

36.5 - 37.5 oC

Question 2

Regarding core temperature, what are humans?

Answer 2

Homeotherms

Endotherms

Question 3

What are the features of homeotherms?

Answer 3

Constant and regulated internal temperature

Question 4

What are the features of endotherms?

Answer 4

Generate heat internally

Maintain high basal heat production

Question 5

What is hypothermia?

Answer 5

Low body temperature

Question 6

What body temperature does hypothermia occur?

Answer 6

<35.0oC

Question 7

What happens if you have hypothermia?

Answer 7

Impaired movement
Coordination
Speech
Cognition

Question 8

What is hyperthermia?

Answer 8

High body temperature

Question 9

What temperature does hyperthermia occur?

Answer 9

> 38.0 oC

Question 10

What causes hyperthermia?

Answer 10

Exercise or fever

Question 11

What temperature does damage to cells occur?

Answer 11

> 42.0 oC

Question 12

What effects skin temperature?

Answer 12

Ambient temp
Distance from core
Skin blood flow

Question 13

What is specific heat capacity?

Answer 13

The amount of energy required to raise the temperature of a given substance by 1oC

Question 14

How much heat energy does 1 litre of O2 consumption produce?

Answer 14

20 Kj

Question 15

What is the law of conversation of energy?

Answer 15

Energy can neither be created of destroyed: It can only be transformed from one state to another

Question 16

What type of reaction is it when we liberate chemical energy from food?

Answer 16

Exothermic

Question 17

What type of reaction is it when we resynthesise ATP?

Answer 17

Endothermic

Question 18

What are the two types of heat production?

Answer 18

Voluntary

Involuntary

Question 19

Provide an example of voluntary heat production

Answer 19

Exercise

Question 20

Provide an example of involuntary heat production

Answer 20

Shivering

Action of hormones

Question 21

What hormones are released to produce heat?

Answer 21

Thyroxine

Catecholamines

Question 22

How is heat gained externally?

Answer 22

Sky thermal radiation
Solar radiation
Ground radiation

Question 23

How is heat lost?

Answer 23

Conduction
Convection
Radiation
Sweat evaporation

Question 24

What is thermal gradient?

Answer 24

Heat transfer is always from higher to lower temperatures

Question 25

What is conduction?

Answer 25

Heat transfer from the body to an object with direct contact (about 3% at rest)

Question 26

What is convection?

Answer 26

Heat transfer to or from air or water (about 12% at rest)

Question 27

What is radiation?

Answer 27

Transfer of heat in the form of electromagnetic waves

Question 28

What is evaporation?

Answer 28

Vaporisation of sweat from water to vapour

Question 29

How much heat do we lose per one gram of sweat?

Answer 29

2.41KJ

Question 30

Where is sweat released from?

Answer 30

The sweat glands

Question 31

What is sweat stimulated by?

Answer 31

Sympathetic nervous system

Question 32

What three things influence evaporation?

Answer 32

Temperature Convective currents Skin exposure

Question 33

How does hyperhermia effect sprint/power performance?

Answer 33

Improves it

Question 34

How does hyperhermia improve sprint/power performance?

Answer 34

``` Decreases resistance of muscles/joints Faster nerve conduction velocity Improvement in muscle contractile elements Faster metabolic rate Increased SNS activity ```

Question 35

How does hyperthermia effect endurance performance?

Answer 35

Impairs it

Question 36

How does hyperthermia effect repeated sprint performance?

Answer 36

Impairs it

Question 37

What are the cognitive consequences of hyperthermia?

Answer 37

``` Fatigue perception increase Scanning vigilance Reaction time Attention Visual motor tracking ```

Question 38

What are the effects of heat acclimation?

Answer 38

Body temp will be lower at a given heat Sweat rate increases and sweat becomes more dilute Skin blood flow is reduced, more blood to muscles Blood volume increases or does not decrease SV maintained