Epithelial Coverings Body armor Epithelial coverings In Vertebrae

Epithelial Coverings Body armor

Epithelial coverings � In Vertebrae skin functions in protection and temperature regulation � In fish, reptiles, and a few mammals the epithelium forms scales � Several types of specialized glands › Mammary glands › Sebaceous glands › Sweat glands

Epithelial coverings � Skin produces many different structures › Skin of birds produce or form feathers. › Skin of mammals form hair, nails, or claws

Epidermis � Waterproof layer � Deepest layer is the Stratum basale › Site for new skin cell production › Some of these cells produce melanin � Upper layer known as stratum corneum › Cells in this layer are keratinized › Keratin waterproofs skin and makes up hair and nails

Dermis � Contains blood vessels and other structures › Collagen strengthens the skin yet allows flexibility › Elastin gives skin its elasticity. Fibrous scleroprotein found in elastic tissues such as walls of arteries. › The dermis contains �Sensory receptors �Sweat glands �Oil glands �Hair follicles are embedded in it

Hypodermis � Located at the base of the dermis � This is a fatty layer important for insulation (white fat). � Infants, hibernating animals, and small rodents that live in cold areas have brown fat. › Brown fat produces heat

Disorders of skin �Athletes foot �Impetigo �Psoriasis