2007-03-07 11:12:58 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Biology
Everybody yawns — from unborn babies to the oldest great-grandparent. Animals do it, too. But why, exactly, do people and animals yawn? No one knows for sure. But there are many theories (ideas) about why people yawn.
One is that when we are bored or tired, we just don't breathe as deeply as we usually do. As this theory goes, our bodies take in less oxygen because our breathing has slowed. Therefore, yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood.
2007-03-07 11:21:00 · answer #1 · answered by Lauren D 4 · 0⤊ 0⤋
When not enough oxygen is taken in, the body tries to inhale very quickly, creating a yawn. Mainly this happens when you are tired because your breathing slows down.
2007-03-07 11:20:08 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Because of lack of oxygen in our blood. When we yawn, we inhale a lot and can get more oxygen to parts of our bodies that need it, ie our brain.
2007-03-07 11:21:01 · answer #3 · answered by Leanne J 2 · 0⤊ 0⤋
I hate this question...it just made me yawn...stupid contagious yawning!!!
Lauren's answer is right though, i'd go with hers.
2007-03-07 15:52:45 · answer #4 · answered by Anonymous · 0⤊ 0⤋
we have specific receptors in our circulatory system that measures the oxygen tension in our blood..so when oxygen decrease, this receptors send impulses or messages to respiratory center in our brain activating all possible mechanisms to increase oxygen including yawn..
2007-03-07 12:02:15 · answer #5 · answered by spiky 1 · 0⤊ 0⤋