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The INTEGUMENTARY System. Functions of the Integumentary System. Guard the body’s physical and biochemical integrity Maintain a constant body temperature Provide sensory information about the surrounding environment . Your Skin. A large organ composed of all 4 tissue types
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Functions of the Integumentary System Guard the body’s physical and biochemical integrity Maintain a constant body temperature Provide sensory information about the surrounding environment.
Your Skin A large organ composed of all 4 tissue types (connective, epithelial, muscular, nervous) Has an area of about 22 square feet Approximately 1-2 mm thick Weighs about 10 lbs
STRUCTURE OF THE SKIN The two major layers of the skin are: Epidermis: the top portion of the skin; composed of epithelial tissue. Dermis: the deeper layer of the skin; primarily composed of connective tissue
Overview of Epidermis Your epidermis……. • Is Avascular (contains no blood vessels) • Contains 4 types of cells: ~keratinocytes, ~melanocytes, ~Langerhans cells, ~Merkel cells • Has 5 distinct layers of cells
Dermis Connective tissue layer Contains hair follicles, glands, nerves & blood vessels
Tattoos Tattooing is a permanent coloration of the skin in which a foreign pigment is injected into the dermis.
Skin Color Pigments The wide variety of colors in skin is due to three pigments -melanin, carotene, and hemoglobin (in blood in capillaries) -in the dermis.
Accessory Structures of Skin • Hair • Oil & Sweat glands • Nails
HAIR Hairs…also known as pili, are present on most skin surfaces: • except the palms, palmar surfaces of the digits • the soles, and plantar surfaces of the digits.
HAIR Hair consists of – a shaft above the surface – a root that penetrates the dermis and subcutaneous layer – the cuticle – a hair follicle
HAIR Structure of Hair • Shaft -- visible • Root -- below the surface • Follicle-- surrounds root
HAIR Arrectorpili Is the smooth muscle in the dermis that contracts with cold or fear. Forms goose bumps as the hair is pulled vertically
HAIR Hair Growth The hair growth cycle consists of a growing stage and a resting stage. Growth stage – lasts for 2 to 6 years Resting stage – lasts for 3 months Old hair falls out as growth stage begins again. Normal hair loss is 70 to 100 hairs per day!
Hair Color Hair color is due primarily to the amount and type of melanin. Graying of hair occurs because of a progressive decline in tyrosinase.
Hair Color • Dark hair contains true melanin • Blond and red hair contain melanin with iron and sulfur added • Graying hair is result of decline in melanin production • White hair has air bubbles in the medullary shaft • Hormones influence the growth and loss of hair.
Functions of HAIR • Prevents heat loss • Decreases sunburn • Eyelashes help protect eyes • Touch receptors (senses light touch)
NAILS • Nails protect the tips of your fingers and toes so that they can remain soft and sensitive • Nails form from nail roots under the skin at the base and sides of nails • As new cells form, the nail grows longer
NAILS Fingernails and toenails are made of a tough protein called keratin, as are animals' hooves and horns.
NAILS The nail consists of the nail plate, the nail matrix and the nail bed below it, and the grooves surrounding A. Nail plate; B. lunula; C. root; D. sinus; E. matrix; F. nail bed; G. hyponychium; H. free margin
Where does nail growth occur? The nail grows from a deep groove in the dermis of the skin. All nail growth occurs at the nail’s base, where the specialized cells that make up the nail’s plate are produced; these cells are pushed forward as new cells form behind them
NAIL GROWTH • In humans, nails grow at an average rate of 3 mm (0.12 in) a month. • Fingernails require three to six months to regrow completely, and toenails require 12 to 18 months. • Actual growth rate is dependent upon age, sex, season, exercise level, diet, and hereditary factors. • Nails grow faster in the summer than in any other season.
Disorders of the NAILS ONYCHOPHAGY Bitten nails, often no free edge is visible. Nails look ragged and distorted, skin and nail bed can be exposed and raw.
Why do fingernails turn blue? When a person's hands are cool, it is possible for these blood vessels to constrict, causing the nails to become more pale or even take on a bluish hue. Not enough oxygen delivery through the blood it is also possible reason
Disorders of the NAILS Pseudomonas • bacterial infection • occur between the natural nail plate and the nail bed, and/or between an artificial nail coating and the natural nail plate • feeds off the dead tissue and bacteria in the nail plate • may also cause the nail plate to lift from the nail bed.
Disorders of the NAILS Fungalor Yeast infection • This type of infection is characterized by onycholysis (nail plate separation) • Appears white or yellowish in color, and may also change the texture and shape of the nail. • The fungus digests the keratin protein of which the nail plate is comprised.
Disorders of the NAILS TineaUnguium • Ringworm of the nail (dermatophyte) • Can be scraped off from the nail plate • Spreads to the nail root • Highly contagious
Wacky Facts About Your Nails 1.Nails and hair do not keep on growing after death contrary to what is often stated as fact. The truth is that the body dehydrates after death, resulting in an appearance of hair and nails that seem to grow. 2.Finger nails grow faster than toe nails. Finger nails grow at the approximate rate of a half an inch every 100 days. If you bite your nails down to the flesh it takes at least a month to re-grow! 3.Nails on longer fingers grow faster than nails on short fingers. Nails also grow faster on your dominant hand. So if you must bite your nails, concentrate on the middle finger of your right hand – if you are right handed. 4.Massaging your finger tips will stimulate nail growth. So does typing on a keyboard. 5.Nails grow much faster during pregnancy
Wacky Facts About Your Nails 6.Dry nails are mostly the result of not drinking enough. Unfortunately only water helps. 7.A man’s nails grow faster than a woman’s. This does not make a man superior. 8.Nails grow faster in warm sunny climates than in cold dark places. If you must bite your nails, move to Southern California. 9.The older you are, the slower your nails grow. 10.People biting nails do this out of habit. There is no medical cure. The only way to stop nail biting is to break the habit!
Oil & Sweat Glands • Sweat glands are known mostly to help regulate temperature by bringing warm moisture to the surface of the skin, which causes cooling as the water evaporates. Also as a detoxifier-rids the body of certain wastes Sweat
Sweat Glands • They are simple tubular glands found in almost every part of the skin • There are two to four million sweat glands distributed all over our bodies • Sweating is controlled from a center in the hypothalamus • Stimulated in response to; 1-high temperature 2-exercise 3- hormones 4-emotional stress
Stress Sweating vs Temperature Induced Sweating • emotionally induced sweating is restricted to palms ,soles , armpits and forehead • temperatureinduced sweating causes sweating throughout the body
Sweat & Its Function • Sweat is the watery fluid produced and excreted by the sweat gland • Thermoregulation: primary function, allows the body to rid itself of excessive heat production • Forms part of the hydrolipid film which is the protective covering keeping the skin in good condition • plays a minor excretory role (some drugs and toxins are excreted in sweat)
Types Of Sweat Glands Apocrine Eccrine
Eccrine • Eccrine sweat is composed mainly of water and small amounts of solutes • Found virtually in all skin
Apocrine • Apocrine sweat consists mainly of mucin which explains its viscosity and large amounts of protein and steroids. • Found in the theaxillae (armpits), areola and nipples of the breast, ear canal & eyelids
Sebaceous (Oil) Glands • Secrete oil or sebum • Found everywhere except palms, soles • Usually secretes into hair follicle • Lubricates hair and skin • Softens dead cells—pliability • Slows water loss • Bactericidal • Stimulated by hormones
Ceruminous glands • This are modified (eccrine) sweat glands in the passageway of the external ear. Their secretions combine w/ sebaceous glands forming CERUMEN….or earwax. Together w/ tiny hairs traps foreign particles.