Test 3: Regulation of Body Temperature Flashcards
Is temperature uniform throughout the body? Explain the ‘parts’ of the body. What are their temperatures?
NO!
1) Inner Core:
- deep body temperature
- measured in the rectum
mammals: 36.5 - 39.5 * C
birds: 38 - 42 * C
2) Outer Shell
What fluctuations in temperature are normal for animals over a 24h period?
0.5-1.0 * C
What is the regular mammal core temperature?
between 36.5 * C and 39.5 * C
What is the regular bird core temperature?
between 38 * C and 42 * C
Explain the distrubution of temperatures in an organism under warm and cold environmental conditions.
Warm conditions:
- the core body temperature extends into the limbs and close to the skin surface of the animal.
Cold conditions:
- vasoconstriction in the peripheral blood vessels results in a gradient of temperatures between the core and the extremities.
- The core temperature is maintained only in the abdomen, thorax, and brain of the animal.
- The more peripheral tissues are allowed to cool considerably.
What influences body temperature?
metabolic rate
Explain the circumstances in which organisms may have hyperthermia. What is hyperthermia?
Hyperthermia- elevated body temperatures
- during excercise
- pregnant, lactating, rapidly growing animals
- thyroid hormone
What affects body temperature restraint?
- internal insulating layers (eg. white and brown adipose)
- external insulating layers (eg. hair and feathers)
What must be achieved in order for an organism to maintain a stable body temperature?
- a stable body temperature:
- heat inpute = heat output
Explain the metabolic rates in endothermic and ectothermic animals. What are they?
Ectotherms:
- low metabolic rate
- cannot regulate body temperature
- internal temperature = environment temperature
- cold-blooded
- all animals except of birds and mammals
Endotherms:
- high metabolic rate
- produce internal heat
- heat produced by the metabolism of food
- warm-blooded
- birds and mammals
How do endothermic animals regulate their body temperature?
gain metabolic heat:
- cellular respiration
- muscular contraction
regulate:
- behaviour (ie. finding shade, panting, reduced activity)
Explain temperature variation over time. What happens in cold-blooded animals? Warm blooded?
Cold-blooded:
- body temperature fluctuates with the external environment
- poikilotherms (“fluctuating heat”)
Warm-blooded:
- body temperature is regulated by internal mechanisms - more stable
- homeotherms (“same heat”)
What happens to all energy of an animal if it is:
- not growing
- not preforming physical work
- not pregnant
- not lactating
?
All energy released from nutrients is converted to heat.
How much faster can heat production become during muscle activity?
20 times higher than at rest
What is an example of involutary muscle contraction created to increase heat production?
shivering