Presentation on theme: "Dermis And Accessory Structures. Majority of cells are keratinocytes “Ashiness” is caused by this layer of dead skin cells being very rough and raggedy."— Presentation transcript:
Smooth muscle attaches to follicle Raises hairs Response to fright or cold Function?
Thermoregulation– less in man than other mammals Sense light touch of the skin Protection – scalp Three concentric layers Medulla (core) Cortex (surrounds medulla) Cuticle (single layers, overlapping) Functions of hair
Hair growth: averages 2 mm/week Active stage: hair is growing Resting phase: no hair growth, then shed At the base of the follicle, hair papilla Contains blood vessels and nerves Nourishes hair Bulb Contains matrix – epithelial cells responsible for growth Contains melanocytes
Hair loss Thinning – age related Male pattern baldness Hair color Amount of melanin for black or brown; distinct form of melanin for red White: decreased melanin and air bubbles in the medulla Genetically determined though influenced by hormones and environment
Entire body except palms and soles Connect to hair follicle
Produce sebum – oily waxy substance Oils and lubricates Can cause blackheads, lead to acne if follicle ruptures from buildup.
All over body Function: Prevent overheating 500 cc to 12 l/day! (is mostly water) Produced in response to stress as well as heat
Merocrine Most numerous True sweat: 99% water, some salts, traces of waste Open through pores Apocrine Axillary, anal and genital areas only Ducts open into hair follices The organic molecules in it decompose with time - odor
When you sweat, heat leaves the body through your pores. When the sweat hits the outer surface of the skin, it is cooled by the air. This lowers your body temperature.
The dermis is attached to underlying organs by the hypodermis (subcutaneous layer) Loose connective tissue Packed with adipose cells Stabilizes position of skin
“ Hypodermis ” (Gk) = below the skin “ Subcutaneous ” (Latin) = below the skin Also called “ superficial fascia ” “ fascia ” (Latin) =band; in anatomy: sheet of connective tissue Fatty tissue which stores fat and anchors skin (areolar tissue and adipose cells) Different patterns of accumulation (male/female)