HSC 3537 Lecture Notes - Lecture 16: Hair Follicle, Subcutaneous Tissue, Sebaceous Gland
Document Summary
Skin: integumentary system: weighs 8 to 10 lbs, covers 22 sq. ft. in the average adult. Hair: cells filled with the hard protein; keratin: hair follicles: shafts that hold the hair. Five million hairs on the body; 100,000 on the head: melanocytes at the root form the color, grows . 5 inch (1. 3 cm) per month, cutting does not affect growth. Nails: hard keratin plates covering the toes and fingers: lunula, cuticle. Sebaceous glands secrete oily sebum into the hair follicle to lubricate. Sweat glands secrete into pores to moisten and cool: both are subject to bacterial growth. Alopecia: the absence of hair where it normally grows. Urticaria: an acute allergic reaction with red, round wheals on the skin. Acne: papular and pustular eruption of skin with increased production of sebum. Burns: injury to tissue due to heat, chemical, electric shock, lightning, or radiation. Cellulitis: a diffuse acute infection of the skin.
