important role is to regulate the movement of materials into and out of cells. The phospholipid bilayer structure (fluid mosaic model) with specific membrane. proteins accounts for the selective permeability of the membrane and passive. and active transport mechanisms.
Structure of Blood Vessels a) Three distinct layers or tunics form the walls of blood vessels: ---The tunica interna (tunica intima) is the innermost layer.It contains the endothelium which is a continuation of the endocardial lining of the heart.tructure of Blood Vessels a) Three distinct layers or tunics form the walls of blood vessels: ---The tunica interna (tunica intima) is the innermost layer.
The stratum corneum (outermost layer of skin) is a zone of approximately four layers of viable cells that are able to synthesize proteins that keep the outer layer of skin smooth and soft.n addition to protection (physical and chemical barrier), the skin serves other functions. It converts modified epidermal cholesterol to a vitamin D precursor important to calcium metabolism.