ANSC 311 Lecture 13

  1. 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)
  2. 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
  3. 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. 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
  5. Mammals and birds keep what kind of core body temperature range
  6. Why must mammals keep such a narrow temperature range
    Temperature sensitive organs in CNS and internaly
  7. Where are heat loss or heat conserving mechanisms coordinated
  8. 2 responses to heat stress
    • Peripheral vasodilation
    • increased evaporative cooling
  9. 2 responses to cold stress
    • peripheral vasoconstriction
    • piloerection - goose bumps
    • increased metabolic heat production via shivering and non shivering thermogenesis
  10. What is a fever?
    elevated body temperature due to an increase in thermoregulatory set point
  11. What is a heat stroke
    When heat production or input exceeds output and body gets to dangerous levels
  12. What is hypothermia
    Occurs when heat output exceeds heat production and body temperature drops to dangerous levels
  13. What is frostbite
    Occurs when ice crystals form in tissue extreemities
  14. In terms of efficiency what is metabolism and work
    • 50% and 25%
    • So they give off alot of heat
  15. During excersise what are 3 ways we blow off heat
    • Conduction (contact)
    • Radiation (skin)
    • Evaporation (sweat)
  16. What is in control of our long term metabolic regulation
    Thyroid gland
  17. Why is shivering such a good way to warm up
    Because it is only 25% efficient
  18. Define shivering
    Uncoordinated contraction fo muscle
  19. Do you have central thermoreceptors?
    • Yes both central and peripheral
    • Central can be in CNS and abdominal organs
  20. Where are both your central and peripheral thermoreceptors integrated to form a response
  21. Give an example of where you would want a counter current heat exchanger
    Testicular artery
  22. 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
  23. Which nervous system causes vasoconstriction
  24. Sympathetic
  25. The vasoconstriction and dilation works only with cappileries close to what?
    The surface of the skin
  26. Which nervous system stimulates sweating
  27. What is an important environemental factor when it comes to the effectiveness of sweating
  28. What is the upper critical temperature
    The highest point of the thermal neutral zone
  29. What is your most important thermotreceptors
    Arteriole blood
  30. Where are the three types of thermoreceptors
    • Arteriole blood
    • CNS
    • Periphery (skin)
  31. What is your set point
    The set point your body will regulate your temperature too
  32. Once we get past the thermal neutral zone what happens to feed intake
  33. Why dont we want to grow animals at colder temperatures, they intake more food?
    Need more energy to stay warm
Card Set
ANSC 311 Lecture 13