Skin, Hair and Nails

Skin 2 Layers of Skin Outer Epidermis Inner supportive Dermis 3 rd Layer of Subcutaneous Adipose

Epidermis Protective Stratified into several zones Basal cell layer = forms new skin cells Keratin = major ingrediant Melanin = # but amt of production varies Uniformly thin except on palms and soles Avascular

Vesicle, Bulla

Skin Color Melanin Carotene pigment Vascular beds in the dermis Affected by skin thickness & edema

Dermis Supportive layer Collagen Elastic quality for stretching Nerves, sensory receptors, bld. vessels, lymphs Epidermis appendages = hair follicles, sebacceous glands, sweat glands embedded in the dermis

Hair Important because? Threads of keratin 2 types Vellus hair- over body Terminal hair

Glands Sebaceous Glands Sebum = protective lipid substance Lubricates hair& skin prevents water loss everywhere but palms & soles Sweat Glands Eccrine = skin surface- sweat Apocrine = thick, milky secretion – axilla, anogenital, nipples, navel.

Nails Keratin Color Condition Shape, Profile sign

Function of Skin Protection Prevents penetration Perception Temperature regulation Identification Communication Wound repair

Function of Skin Absorption & excretion Vitamin D – ultraviolet light > cholesterol