NSE 13A/B Chapter Notes - Chapter 13: Vellus Hair, Stratum Corneum, Vernix Caseosa
8 May 2015
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Document Summary
Skin has two layers: outer, highly differentiated epidermis, inner supportive dermis. Beneath these layers is a third layer, the subcutaneous layer of adipose tissue. Cells bound tightly together and strati ed into several zones. From basal layer, new cells migrate up and atten into stratum corneum. Consists mostly of connective tissue, or collagen resists tearing; elastic tissue. Nerves, sensory receptors, blood vessels, and lymphatic vessels lie here. Appendages from epidermis hair follicles, sebaceous glands, and sweat glands embedded here. Stores fat: for energy, providing insulation for temperature control, protection. Loose layer gives skin incr. mobility over structures underneath. Formed by tubular invagination of epidermis down into underlying dermis. Is now vestigial for humans no longer needed for protection from cold or trauma: highly signi cant in most cultures for its cosmetic and psychological meaning. Hair shaft visible projecting part, root is below the surface. At root is the bulb matrix expanded area where new cells produced at fast rate.
