What is critical for the function of proteins in the human body?
Maintenance of body temperature within a narrow range
What are the factors that effect the "normal" body temperature?
Gender
Time of day
Reproductive cycle
WHether you are an early bird or a night owl
We regulate body temperature within a narrow bound. Body temperature above _______ and below _______ can cause serious damage or be fatal.
41oC
24oC
The change in our body temperature depends on 5 processes
Metabolism
Evaporation
Convection
Conduction
Radiation
Is metabolsim an efficient process?
No
What is the efficiency of metabolism?
20%
What are the factors that can change metabolism?
Size
Gender
Age
feeding state
Shivering thermogenesis
Non-shivering thermogenesis
What composes the metabolic heat production?
IS the portion of total energy you burn that is lost as heat
The total energy you burn is your metabolic rate
The percent of that total energy that goes towards useful work is your efficiency (around 20%)
What does an uncoupling protein do?
Converts stored energy in a proton gradient into heat
What UCP is found BAT and is important for thermogenesis?
UCP1
Where is UCP2 found and what does it do?
Found in BAT, WAT, skeletal muscle and beta cells
PLays a role in ROS removal
What does an increased expression of UCP2 in beta cells do?
INcreased risk of diabetes type II
The increase expression leads to reduced insulin production in response to glucose
Metabolic heat expression = ( )*( )*( )
(B)(Stotal)(0.8)
(Basal metabolic rate)(Surface area total on body)(1-efficiency)
What does evaporate heat loss depend at?
Depends on the difference in water vapor pressure between the skin and the surrounding air
What happens if the water vapor pressure is higher at the skin?
Then water will evaporate to the surrounding air
What happens when water vapor pressure is lower at the skin?
Then the water will codense on the skin
What surface area does evaporation depend on?
The wetted surface area
How do you find the evaporation constant?
Look at the graph and show that you followed the numbers
What is evaporation equation?
(hevaporative)(Swetted)(WVPskin-WVPair)
What is convection heat exchange?
Heat transfer by the movement of fluid molecules
What does convection heat exchang depend on?
The temperature difference between the air close to the skin and the surrounding air
The surface area of skin exposed to air
The convective heat transfer coefficient
What is the convection equation?
(hconvective)(Swetted)(Tskin-Tair)
How do you find convection heat exchange constant?
Look at the graph but be careful to look at the right axis
What is heat exchange by conduction?
HEat exchange between surfaces in contact with a surface
WHat does heat exchange by conduction depend on?
THe temperature difference between the skin and the surface
The surface area of skin touching the surface
The conductive heat transfer coefficient
WHat is the heat exchange by conduction equation?
(hk)(Sk)(Tskin-Tsurface)
What is heat exchange terrestrial radiation?
The amount of long wavelength terrestrial radiation we gain or lose depends on the difference between the temperature of our skin and the temperature of our surroundings
the surface area exposed to our surroundings and the radiative coefficent
What is the heat exchange by terrestrial radiation?