Cytology, General Histology and Embryology - V. K. Naphanyuk 2002

Cytology
Cell wall

A common feature in the Structure of Cell membranes is that they are thin lipoprotein layers ranging from 6 to 10 nm in thickness.

The Cell membrane (Plasmalemma) holds a special place among various cellular membranes. It is a surface peripheral structure that bounds the cell from the outside, determining its direct connection with the extracellular environment and, consequently, with all substances and Factors affecting the cell.

The cell membrane consists of three layers:

— the outer (supra-membrane) layer — the glycocalyx (glicocalyx);

— the membrane proper (biological membrane);

— the submembrane plate (cortical layer of the plasmalemma). The glycocalyx has a thickness of 3-4 nm and is characteristic of virtually all animal Cells, though to varying degrees. The glycocalyx is formed by a glycoprotein complex associated with the plasmalemma, which includes long, branched polysaccharide chains.

The membrane proper (biological membrane) consists of a continuous lipid bilayer in which protein molecules are partially or fully embedded. The thickness of this layer is 5-7 nm.

The submembrane plate (cortical layer) is formed by the densest part of the Cytoplasm, consisting of microfilaments and microtubules that form a network.

Functions of the Cell Membrane

The Main Functions of the cell membrane are as follows:

— compartmentalization;

— metabolite transport (passive or active);

— reception;

— facilitation of Intercellular junctions.