temperature regulation - lesson 1

Question 1

define homeostasis

Answer 1

maintenance of a constant internal enviroment

Question 2

what is the body’s core temperature?

Answer 2

37 degrees celsius

Question 3

why does the body have an optimum temperature?

Answer 3

• ## All chemical reactions within the body occur most optimally at this temperature

Question 4

define ambient temperature

Answer 4

the temperature of the environment the athlete is performing in

Question 5

define core temperature

Answer 5

the temperature inside the athlete’s body

Question 6

what happens when the body needs to lose heat?

Answer 6

vasodilation
- blood vessels
to the skin surface increase their diameter
- increasing blood flow to the skin so heat loss can occur via sweating

Question 7

what happens when the body needs to retain heat?

Answer 7

vasoconstriction

• blood vessels to the skin decrease their diameter
• less blood is sent to the skin surface so heat loss is minimized
• result in a loss of fine motor skills

Question 8

what are the 4 mechanisms that transfer heat?

Answer 8

conduction
convection
radiation
evaportation

Question 9

what is conduction?

Answer 9

• Heat exchanged by two objects in contact
• significant in water sports
  E.G. ice vest, heat pack or running on hot road

Question 10

what are the factors that determine the rate at which conduction occurs?

Answer 10

• Difference in temperature between the 2 surfaces > The greater the temperature difference
  = the faster the rate of conduction.
• Surface area > The greater the surface area the greater the heat loss
• Thermal conductivity of material

Question 11

what is convection?

Answer 11

heat exchange by contact with a fluid that is flowing

• occurs when heat is carried away from the body by air or water currents
• most effective when temp surrounding body is low

Question 12

what is radiation?

Answer 12

occurs when heat is transferred from a warmer body to the cooler surroundings without physical contact. It is the transfer of heat via electromagnetic waves

Question 13

what is evaporation?

Answer 13

the cooling of the body as a result of the vaporisation of sweat.
- Evaporation provides the most significant heat exchange when exercising in moderate to warm conditions

Question 14

how does evaporation work?

Answer 14

• Heat from the blood is transferred to the sweat molecule and the skin is cooled when the sweat evaporates
• Increased blood flow to the skin and heat loss occurs as a result of vasodilation of blood vessels
• Evaporation of sweat on skin creates cooling effect
  = cooled skin cools blood travelling to skins surface

Question 15

what does rate of sweating depend on?

Answer 15

• Gender (male more than female)
• Number of sweat glands
• Body surface area (↑SA = ↑ sweat)
• How fit you are (↑fitness = ↑ sweat if all other factors are equal e.g. body SA)