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.
1 Skeletal cartilages are made from cartilage, surrounded by a layer of dense irregular connective tissue called the perichondrium. 2  Hyaline cartilage is the most abundant skeletal cartilage, and includes the articular, costal, respiratory, and nasal cartilages. Basic Structure, Types, and Locations. 2  Skeletal cartilages are made from cartilage, surrounded by a layer of dense irregular connective tissue called the perichondrium.