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.
cartilage lacuna. any of the small cavities within the cartilage matrix, containing a chondrocyte. Howship's lacuna. the concave cavities which are formed by osteoclasts in the process of bone resorption.osseous lacuna. bone lacuna (see above).acuna, absorption (Howship's lacuna), n an area (pit) of bone resorption, usually irregular in outline, and often containing osteoclasts.