Re: Can an infant breathe and swallow simultaneously?

Can an infant breath and swallow simultaneously?

The pharynx (the combination of your air and food tube) was surrounded by 
branchial arches during embryological development. The substance of the 
arches form most of the bony structures of the face and throat. These 
arches are often called "gill arches" in the developing embryo, because 
that is what they look like. But they are not gills -- at least not gills 
in the same sense as when we say that a fish has gills. They may be 
holdovers from our Devonian ancestry (about 450 million years ago), but 
then it would be more correct to say that fish gills and land animal faces 
both develop from the branchial arches.

One of the innovations associated with the evolution of mammals was the 
development of mammary glands (the defining characteristic of a mammal) and 
the nursing young. Some young mammals will attach their mouths to the 
nipple almost continuously. In this case, they need to drink milk and 
breath at the same time. The innovation that allows this is the palate and 
the high location of the larynx (the voice box and the beginning of the air 
tube).

A nursing mammal can suck milk into its mouth, and thanks to the palate its 
mouth is separate from its nasal cavity. So while it is sucking in milk, it 
can also breath through its nose. When the mammal is ready to swallow, the 
soft palate (the back of throat with the dangling uvula attached to it) 
rapidly moves upward to close off the back of the nasal air tube. At the 
same time, the epiglottis closes off the larynx and guides the milk into 
the esophagus (the food tube). Because of these innovations, the young 
mammal can breath and swallow in quick succession. It is not  simultaneous, 
but it is pretty close.

Humans add an extra wrinkle to this problem. Although we are born with a 
fairly typical mammalian pharynx, the larynx moves down to a lower position 
in our throat as we grow older. This leaves a large gap between  the back of 
the mouth and the top of the larynx. For adult humans, the act of swallowing 
becomes a very delicate process. The fact that we frequently choke on "food 
going down the wrong tube" shows how easily this process can be disrupted.