two layers

The cell membrane consists of three classes of amphipathic lipids: phospholipids, glycolipids, and sterols.

With few exceptions, cellular membranes — including plasma membranes and internal membranes — are made of glycerophospholipids, molecules composed of glycerol, a phosphate group, and two fatty acid chains. Glycerol is a three-carbon molecule that functions as the backbone of these membrane lipids.

Tarsal conjunctival True membrane A true membrane forms when the fibrinous excretory or inflammatory exudate that is secreted by invading microorganisms or ocular tissues permeates the superficial layers of the conjunctival epithelium.

-mucous (mucosa) -serous (serosa) -cutaneous (skin or integument) -synovial (not true membrane because there is no epithelium)

Epithelial membranes are composed of both epithelial tissue and connective tissue. These membranes are found lining the external body surface (cutaneous membranes and mucous membranes) or lining the internal body cavities (serous membranes).

• Epithelial cells.
• Pseudostratified epithelium.

Chondrocytes rely on diffusion to obtain nutrients as, unlike bone, cartilage is avascular, meaning there are no vessels to carry blood to cartilage tissue. This lack of blood supply causes cartilage to heal very slowly compared with bone.

Skeletal muscle cells are like nerve cells (neurons): once they are made during the initial stages of development, they never reproduce again. So you have a fixed number of muscle cells in your body, and if one dies, it is not replaced.

Dead cardiac muscle tissue is replaced by scar tissue, which cannot contract. As scar tissue accumulates, the heart loses its ability to pump because of the loss of contractile power. However, some minor regeneration may occur due to stem cells found in the blood that occasionally enter cardiac tissue.