Yawning

@Alloy42 (372)
United States
March 4, 2007 10:04am CST
I've heard there are two causes for yawning 1) lack of oxygen in the air and 2) being tired. It seems to be the body's response to get more oxygen/energy. So which muscles does it involve? Just the ones in the face and neck? The ones in your abdomen as well? Why are they contagious? Low energy levels amongst the same group or maybe just not enough oxygen around everyone? Are there any other times you yawn?
1 person likes this
1 response
helpful_ideas
@helpful_ideas (1620)
• United States
7 May 07
Hmm, what about the broedom yawn? A combination between the two types? I know when you yawn the soft pallet is raised, other than that I have no other input on yawning.