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ANSC 311 Lecture 13
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What are three ways to produce heat when in a cold environment
Metabolism
Shivering (muscle contractions)
Non shivering thermogenesis (basal metabolic rate of fat oxidation)
How is most heat transfered around the body? Why is this?
Through the blood
Because tissues are bad conductors making this the most efficient way
What is a counter current heat exchanger and what is it used for
It is a system in where The veins and or arteries wrap around eachother and exchange heat between the two to direct heat to certain areas
Used to either conserve or lose heat
4 ways to move heat around, describe them
Convection - when body warms air or water
Conduction - when body contacts a cooler surface
Radiation - When infrared radiation by the body is absorbed by cooler objects
Evaporation - when water in sweat, saliva, and respiratory secretions is converted to water vapor
Mammals and birds keep what kind of core body temperature range
Narrow
Why must mammals keep such a narrow temperature range
Temperature sensitive organs in CNS and internaly
Where are heat loss or heat conserving mechanisms coordinated
Hypothalamus
2 responses to heat stress
Peripheral vasodilation
increased evaporative cooling
2 responses to cold stress
peripheral vasoconstriction
piloerection - goose bumps
increased metabolic heat production via shivering and non shivering thermogenesis
What is a fever?
elevated body temperature due to an increase in thermoregulatory set point
What is a heat stroke
When heat production or input exceeds output and body gets to dangerous levels
What is hypothermia
Occurs when heat output exceeds heat production and body temperature drops to dangerous levels
What is frostbite
Occurs when ice crystals form in tissue extreemities
In terms of efficiency what is metabolism and work
50% and 25%
So they give off alot of heat
During excersise what are 3 ways we blow off heat
Conduction (contact)
Radiation (skin)
Evaporation (sweat)
What is in control of our long term metabolic regulation
Thyroid gland
Why is shivering such a good way to warm up
Because it is only 25% efficient
Define shivering
Uncoordinated contraction fo muscle
Do you have central thermoreceptors?
Yes both central and peripheral
Central can be in CNS and abdominal organs
Where are both your central and peripheral thermoreceptors integrated to form a response
Hypothalamus
Give an example of where you would want a counter current heat exchanger
Testicular artery
Vasodilation can increase blood flor by how many times? The blood flow is regulated by what blood vessel? and what nervous system?
6
Arteriole
Parasympathetic
Which nervous system causes vasoconstriction
Sympathetic
The vasoconstriction and dilation works only with cappileries close to what?
The surface of the skin
Which nervous system stimulates sweating
Sympathetic
What is an important environemental factor when it comes to the effectiveness of sweating
Humidity
What is the upper critical temperature
The highest point of the thermal neutral zone
What is your most important thermotreceptors
Arteriole blood
Where are the three types of thermoreceptors
Arteriole blood
CNS
Periphery (skin)
What is your set point
The set point your body will regulate your temperature too
Once we get past the thermal neutral zone what happens to feed intake
Decreases
Why dont we want to grow animals at colder temperatures, they intake more food?
Need more energy to stay warm
Author
Anonymous
ID
213014
Card Set
ANSC 311 Lecture 13
Description
Thermoregulation
Updated
2013-04-12T03:42:31Z
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