Skin and Body Membranes

Epithelial Membranes Cutaneous Membrane Skin Dry Membrane Mucous Membrane Line cavities that open to exterior “wet” membranes Serous Membrane Line closed body cavities Helps protect organs

Connective Tissue Membranes Synovial membranes Line the interior of joint capsules Provide smooth surface and secrete a lubricating fluid

Epidermis Keratinocytes (keratin cells) Fibrous protein Protective layer Other Layers Stratum basale (deepest) Stratum spinosum Stratum granulosum Stratum lucidum Startum corneum

Dermis Papillary layer Upper layer of dermis Reticular layer Deepest layer of skin

Cutaneous Glands (exocrine) Sebaceous (oil) glands Releases sebum (moistens skin) Sebum can kill bacteria Sweat Glands Eccrine glands Produce sweat Apocrine Axillary and genitals only

Hair and Hair Follicles Root Enclosed in follicle Shaft Portion outside skin Arrector pili Smooth muscle that makes your hair stand up when scared

Nails Scalelike modification of epidermis Look pink because of blood supply below Lunula- white crescent at bottom of nail

Infections and Allergies Athlete’s Foot Fungus Boils and Carbuncles Inflamed hair follicles Cold Sores Blisters caused by herpes virus

More Infections and Allergies Contact Dermatitis Ex poison ivy Impetigo Staph infection Psoriasis Epidermal lesions

Burns First Degree Only epidermis damage Second Degree Epidermis and upper layer of dermis Third degree Entire thickness of skin

Skin Cancer Basal Cell Carcinoma Least malignant most common Squamous Cell Carcinoma Common on scalp, ears, dorsum of hands, and lower lip Malignant Melanoma Often deadly