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Integumentary System Accessories. Hair Hair Functions Helping to maintain warmth – Cold stimulates muscles (arrector pili) to erect hairs which traps.

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Presentation on theme: "Integumentary System Accessories. Hair Hair Functions Helping to maintain warmth – Cold stimulates muscles (arrector pili) to erect hairs which traps."— Presentation transcript:

1 Integumentary System Accessories

2 Hair

3 Hair Functions Helping to maintain warmth – Cold stimulates muscles (arrector pili) to erect hairs which traps warm body heat next to skin Alerting the body to presence of insects on the skin – root hair plexus (sensory nerve endings) wraps around each hair bulb Bending a hair stimulates these endings hairs act as sensitive touch receptors Guarding the scalp against physical trauma, heat loss, and sunlight

4 Hair Distribution & Types Distribution – Hair is found over the entire skin surface except: Palms, soles, and lips Nipples and portions of the external genitalia Hair Types: – Vellus – pale, fine body hair found in children and the adult female – Terminal – coarse, long hair of eyebrows, scalp, axillary, and pubic regions

5 Hair Thinning and Baldness Alopecia – hair thinning in both sexes True, or frank, baldness – Genetically determined and sex-influenced condition – Male pattern baldness – caused by follicular response to DHT

6 Hair strands of dead keratinized cells – Has hard keratin which is tougher and more durable than soft keratin of the skin – produced by hair follicles Color comes from melanocytes at the base of the hair

7 Hair Follicle Root sheath extending from the epidermal surface into the dermis – 4 layers thick (from inside out): Internal epithelial root sheath External epithelial root sheath Glassy membrane Connective tissue root sheaths Deep end of follicle forms a hair papilla where shaft grows out of

8 Hair Follicle Figure 5.5c

9 Hair Shaft Consists of 3 parts – Medulla- middle column – Cortex- surrounds medulla, contains color (pigment granules) – Cuticle- outermost layer, made of overlapping cells (scales)

10 Glands

11 Sweat Glands Eccrine sweat glands – – found in palms, soles of the feet, and forehead Apocrine sweat glands – – found in axillary (armpit) and anogenital areas Ceruminous glands – – modified apocrine glands – in external ear canal – secretes cerumen (ear wax) Mammary glands – – specialized sweat glands that secrete milk

12 Sebaceous Glands Found all over the body Soften skin when stimulated by hormones Secrete an oily secretion called sebum – Found near hair follicles

13 Fingernails

14 Structure of a Nail Scalelike modification of the epidermis on the distal, dorsal surface of fingers and toes Figure 5.6


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