Membranes Anatomy Ch. 4 Section 1

Functions of Body Membranes Cover surfaces Line body cavities Form protective sheets around organs Form lubricating sheets around organs Fall into 2 major groups which are classified by tissue make up: Epithelial Cutaneous Mucous Serous Connective Synovial

Cutaneous Membrane The skin Epidermis composed of stratified squamous epithelium Dermis is composed of composed of dense connective tissue Subcutaneous layer is composed of adipose tissue Held to underlying organs by loose connective tissue The only dry membrane because it is exposed to the air.

Mucous Membranes (Mucosa) Most mucous membranes contain stratified squamous, simple columnar, or pseudostratified epithelia. Rests on a loose (areolar) connective membrane called the lamina propria. Lines all the body cavities that open to the outside. Found in the respiratory, digestive, urinary, and reproductive tracts. Wet membranes Function in absorption or secretion

Serous Membranes (Serosa) Simple squamous epithelium Rests on thin areolar (loose) membrane Line body cavities that are closed to the exterior Occur in pairs forming 2 layers around organs. It is actually one membrane that folds on itself. The 2 layers are separated by serous fluid. The serous fluid allows organs to slide past each other and against cavity walls easily.

Two layers of serous membranes Parietal: lines the wall of a body cavity Visceral: covers the organs in the cavity Examples of serous membranes Peritoneum: lines abdominal cavity and organs Pleura: lines the lungs Pericardium: lines the heart

Mucous membranes line body cavities open to the exterior.

Serous membranes line body cavities closed to the exterior. Parietal peritoneum Parietal pericardium Visceral peritoneum Visceral pericardium Visceral pleura Parietal pleura Serous membranes line body cavities closed to the exterior.

Synovial Membranes No epithelial tissue Soft areolar (loose) connective tissue Surround joint cavities Provide a smooth surface and secrete a lubricating fluid called synovial fluid Line bursae and tendon sheaths, both of which cushion organs that move against each other during muscle activity. A bursae is a fluid filled sac found between bones and tendons A tendon sheath surrounds a tendon which connects muscle to bone.

Joint cavity (contains synovial fluid) Ligament Articular (hyaline) cartilage Fibrous capsule Articular capsule Synovial membrane