Thermoregulation Flashcards
What is Thermo regulation?
The control of body temperature.
Explain the effect of vasodilation of arterioles next to the skin 
Relaxation of smooth, muscle cells in arteries causes an increase in blood flow
Blood vessels, dilate blood flow increases due to decrease in vascular resistance
More warm blood at the skin surface this leads to increased heat loss
Greater volume of blood at the surface, which leads to sweating
Movement of blood into the arteriole leads to a decrease in arterial blood pressure 
State two symptoms of hypOthermia
Shivering, dizziness, dilated pupil, vasoconstriction
State two symptoms of hypERthermia
Fatigue, sweating, panting, dehydration
Explain the role of skin in excretion
Sweating, removal of urea, osmoregulation
How do endothermic animals maintain their normal body temperature
Sweating leads to evaporative cooling, reducing high body temp
Vasodilation increases blood supply to surface allowing diffusion of heat
Shivering increases metabolic rate produces heat
Thermoregulation via hypothalamus, negative feedback
Ways animals loose body heat
sweating, flapping ears, vasodilation, excretion, bathing
How is temperature controlled as part of homeostasis
The body detects changes and responds to correct them to a set point by negative feedback
Normal body temperatures
Human- 36.1-37.2
Dog- 37.9-39.9
Pig-38.7-39.8
Chicken-40.6-43.0
Name the parts of the brain that are stimulated when an animal gets
Too hot- heat loss centre of the hypothalamus
Too cold- heat gain of the hypothalamus
The effect of vasoconstriction
Arterioles constrict, less blood flows to the skin reduces heat
Compare behavioural mechanisms used my endotherms in high and low temperature
High temperatures- stretching out body, seeking shade, moving less
Low temperatures- curling up smaller surface area prevent heat loss, moving to warm areas, increase movement
3 ways endotherms maintain a consistent body temperature at low temperatures
Vasoconstriction reducing blood flow to the skin
Piloerection raises hairs or feathers trap a layer of insulating air to reduce heat loss
Shivering
Behavioural changes, reduce heat loss, promote heat gain
How does counter current blood flow function
Counter current heat exchange is an alternative to insulation on the limbs
Limbs are thin and have a legs surface area making them prone to heat loss
Arterial blood is warm as it originated from the core of the animal
Venous blood in the limbs will be cold as it’s returning from the areas furthest away from the core
When arteries and veins pass, the heat from the arterial blood passes to the venous blood
Arterial blood entering the peripheries progressively cools as it moves down the limb
The heat is carried back towards the core via the venous blood
Less heat is lost by the animal
Meaning less energy will be required to maintain the core body temp
Negative feedback-
The body detects changes and then responds to correct them to a set point by negative feedback loop
