Chapter 4 Pages 109 - 112 Body Membranes

Body Membranes Two major groups: Epithelial membranes Cutaneous Mucous Serous Connective tissue membranes Synovial membranes

Epithelial Membranes Aka: covering and lining membranes Not exactly true epithelium DO contain and epithelial sheet ALSO combined with underlying layer of connective tissue

Cutaneous Membrane Skin – superficial epidermis composed of keratinizing stratified squamous epithelium Dermis is mostly dense connective tissue Dry membrane Exposed to air

Mucous Membranes Epithelial layer resting on loose connective tissue called lamina propria. Lines all body cavities that open to the exterior (hollow organs) Respiratory Digestive Urinary Reproductive Mucosa refers to location Mostly stratified squamous epithelium Some simple columnar All are “wet” or moist Mucosae often adapted for secretion or absorption

Serous Membranes Two layers of simple squamous epithelium resting on thin layer of areolar connective tissue Lines cavities closed to the exterior (exceptions: dorsal can joint cavities) Membranes occur in pairs Parietal (“wall”) layer lines a portion of the wall of the ventral cavity and folds in on itself The inner layer is the visceral layer which covers the outside of the organs in that cavity

Serous Membranes Cont. Serous layers are separated by small quantity of serous fluid Secreted by both membranes, keeps them in contact with each other Allows organs to slide with zero friction Name of serosae depends on location Peritoneum – abdominal cavity and covering organs Pleura – membrane surrounding the lungs Pericardium – membrane surrounding the heart

Connective Tissue Membranes Synovial membranes Soft areolar CT and no epithelial cells Line fibrous capsules surrounding joints Provide smooth surface Secrete lubricating fluid Also line small sacs of CT called bursae and tube-like tendon sheaths Both cushions organs moving against each other during muscle activity

Did you get it? How do the body locations of serous and mucous membranes differ? A scalpel penetrates the left lung and enters the heart. Name the six serous membrane layers the blade passes through as it moves from the body surface into the heart. Where would you find a synovial membrane?