Summary NR 302 Exam 2 Concept Review.pdf

CH.12 Structures and functions of skin, hair, nails Skin: 3 layers 1. Epidermis (outer): thin but tough, cell are bound tightly together that form a ruggedprotective barrier. The inner basal layer forms new skin cells. 2. Dermis: is the inner supportive layer consisting of connective tissue, or collagen . This is tough , fibrosis area that enable skin to resist tearing. The sensory receptor, blood vessel,and lymphatics lie in the dermis. 3. Subcutaneous layer: composed of adipose tissue, which is made up of lobules of fat cells. This layer store fat for energy, provide insulation for temperature control , aid in protection by its soft cushion effect. Hair: are threads of keratin composed of 3 parts 1. Hair shaft: visible, projecting part 2. Hair root: Below the surface embedded in the follicle. 3. At the root, Hair bulb: Is expanded area where the new cell are produced in high rate.There are 2 types of hair 1. Vellus hair (fine, faint): Cover most of the body (Except the palm, soles, dorsa anddistal part of the fingers, umbilicus, penis glans, inside the labia) 2. Terminal hair: The darker, thicker hair that grows on the scalp and eyebrows and afterpuberty, on the axillae, pubic area, the face and chest in the male. Nail: Hard plate of Keratin on the dorsal edges of the finger and toes.