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 new cells then move up toward the surface of the skin. --The stratum corneum is the outermost layer of keratin-filled cells. --The pigment-containing cells are called melanocytes, which produce the brown pigment melanin. --The dermal-epidermal junction is a specialized area between two primary skin layers.