In order to answer why the cell would need aquaporins when the plasma membrane is permeable to water, we need to understand the make-up of water and the cell membrane. The water molecule is polar with its H+ and OH- ions. Cell membranes are selectively permeable.
Anatomy of the Auricle. The auricle or pinna is a relatively large appendage on the side of the head. It is prominent in most people and plays a very important role in hearing â it directs sound waves into the ear canal. The auricle is composed of cartilage which is covered by skin.
The outer ear comes in all types of shapes and sizes. This structure helps to give each of us our unique appearance. The medical term for the outer ear is the auricle or pinna. The outer ear is made up of cartilage and skin. There are three different parts to the outer ear; the tragus, helix and the lobule. EAR CANAL The ear canal starts at the outer ear and ends at the ear drum.