BRAINCAKECooling The Brain
The brain is very sensitive to temperature, and its neurones and enzymes can be damaged if it gets much hotter than normal. Some mammals, including gazelles, sheep, goats, cats and dogs, can keep the brain cooler than the rest of the body. This is called selective brain cooling.
It works by countercurrent heat exchange at the base of the brain:
• The carotid artery carrying blood to the brain divides into a network of many small arteries called the carotid rete.
• The carotid rete lies in a pool of venous blood, the cavernous sinus.
• This venous blood has come from the nose, where it was cooled by evaporation of water from the moist lining of the nasal passages as the animal breathes or pants.
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Key terms in this lesson
- carotid rete
- A network of small arteries at the base of the brain that cools arterial blood by countercurrent exchange with cooler venous blood from the nose.
- cavernous sinus
- A pool of cool venous blood, cooled by evaporation in the nose, that surrounds the carotid rete.
More in Homeostasis
- Keeping Warm
- Control of Core Body Temperature
- Vasodilation
- Vasoconstriction
- Adaptations for Cold Environments
- Adaptations for Hot Environments
- Behavioural Control of Body Temperature
- Cape Ground Squirrel
All 41 lessons in Homeostasis · All Edexcel A-level Biology topics