The document summarizes the structure and functions of skin, hair, and nails. It describes the three layers of skin - the epidermis, dermis, and subcutaneous layer. The epidermis is protective and stratified, while the dermis provides support. Hair comes in two types - vellus and terminal hair. Glands in the skin include sebaceous and sweat glands. Nails are made of keratin and can provide signs or clues. The main functions of skin are protection, perception, temperature regulation, identification, communication, wound repair, absorption, and excretion.

1. Skin, Hair and Nails

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

3. 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

10. Vesicle, Bulla

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

14. 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

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

16. 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.

17. Nails Keratin Color Condition Shape, Profile sign

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

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