Posts Tagged ‘Biology’
What is the purpose of yawning?
Friday, June 17th, 2011
Yawning is an involuntary respiratory reflex, which regulates the carbon dioxide and oxygen levels in the blood.
A yawn is commonly triggered either by fatigue or boredom and when a person is tired or bored the breathing is not regulated and it is shallow, and little oxygen is carried to the lungs by the oxygen-toting cardiovascular system.
Yawning elevates ones alertness, as the sudden intake of oxygen increases the heart rate, rids the lungs and the bloodstream of the carbon dioxide buildup, and forces oxygen through blood vessels in the brain, while restoring normal breathing and ventilating the lungs.
Yawning is a kind of physiological mechanism that is designed to maintain attention and regulate our breathing.
Tags: Biology, yawn
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Why don’t tortoises die from starvation and thirst when they are hibernating?
Monday, November 1st, 2010
To answer this question we should first ask ourselves why they need to eat and drink in the first place. Any animal, also a tortoise, needs food to provide it with energy. It needs energy to power its muscles, and keep its body temperature constant in the face of changes in the enviromental temperature.
It needs water because its body (like any animal) is to a great extent made up of water. But there is a continuous loss of water through sweating and the production of urine. Sweating contributes to cooling of the body, and urine will excrete some of the waste that is produced when the animal extracts energy from its food.
Tags: Biology, hibernation, tortoises
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