Integumentary System NMAT

INTEGUMENTARY SYSTEM:

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1.Protection 2.Sensation 3.Vitamin D production 4.Temperature regulation 5.Excretion

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HYPODERMIS: -foundation of the skin -called SUBCUTANEOUS TISSUE. -it is the loose connective tissue that contains about half the body’s stored fat although the amount and location vary with age, sex and diet. -can be used to estimate body fat. SKIN 1.DERMIS- dense collagenous connective tissue that makes up the dermis. -CONTAINS: 1.Fibroblasts 2.Fat cells 3.Macrophages -fewer fat cells and blood vessels. Responsible for the structural strength of the dermis: 1.Collagen 2.Elastic fibers Striae or stretchmarks- are lines that develop during pregnancy.

Are also coated and surrounded by lipids, which help prevent fluid loss through the skin. Composed of 25 or more layers of dead squamous cells.

Denosomes-joins the dead squamous cells. -

When denosomes break apart, and the cells are sloughed through the skin.

Dandruff- dead cellsthat are sloughed from the surface of the scalp. Callus- thickened area produced by number of layers in the stratum corneum. Corn- stratum SKIN COLOR: Melanin- group of pigments responsible for the hair, skin, eye color. -provides protection against UV rays. MELANOSOMES-are produced by the golgi apparatus of the melanocyte.. -move into cell processesof the melanocytes. -all races have the same amount of melanin.

DERMAL PAPILLAE- projections in the upper part of the dermis. They extend towards the epidermis. PURPOSE: ridges increases friction and improve the grip of the hands and feet.

Epithelial cells- phagocytise the tips of the melanocytes cell processes.

Incision made across cleavage lines can gap, increasing the time needed for healing and result in increased scar tissue. Made parallel to cleavage lines results in less gapping, faster healing, less scar tissue. 2.EPIDERMIS: -stratified squamous epithelium; cells are produced by mitosis. KERATINIZATION- cells change in shape and chemical composition. KERATIN- makes the cell hard. STRATA- recognized during keratinisation STRATUM BASALE- consists of cuboidal or columnar cells that undergo mitotic divisions every 19 days. STRATUM CORNEUM- most superficial stratum of the epidermis. Consists of dead, squamous cells filled with hard protein keratin; that gives the corneum its structural strength.

ALBINISM-recessive agent trait that causes a deficiencyor absence of melanin.

Melanocytes----Melanin-----epithelial cells

Increase in melanin production during pregnancy: 1.Estrogen 2.Melanocyte stimulating hormone. Cyanosis- decrease in blood oxygen content that produces a bluish color. Carotene- yellow pigment found in plants such as squash. -lipid soluble; it accumulates in the lipids of the stratum corneum and in the fat cells of the dermis and hypodermis. -gives the skin the yellowish tint

ACCESSORY SKIN STRUCTURES: Hair- one of the characteristics common to all mammals. -

It is thick and covers most of the body surface. (FUR)

Contraction of arrector pili: causes the hair to become more perpendicular to the skins surface or to stand on the end and also produces a raised area of skin called goosebumps. GLANDS:

Shaft- protrudes above the surface of the skin.

MAJOR GLANDS OF THE SKIN:

Root and Hair bulb- below the surface.

1. Sebaceous

Cortex- surrounds a softer center; Medulla.

- simple, branched acinar glands.Connected by a duct to the superficial part of the hair follicle.

Cuticle- single layer of overlapping cells that holds the hair in the hair follicle. Hair Follicle- extension of the epidermisdeep into the dermis; it plays an important role in tissue repair. EPIDERMIS is damaged; the epithelial cells within the hair follicle can divide and serve as a source of new epithelial cells. Hair- produced in the hair bulb, which rests on a dermal papilla. BLOOD VESSELS WITHIN THE PAPILLA- supply the hair bulb with the nourishment needed to produce the hair.

-production of sebum. SEBUM- oily, white substance rich in lipids. -lubricates the hair and the surface of the skin, which prevents drying and protects against bacteria. 2.SWEAT GLANDS A. Merocrine Sweat Glands - simple, coiled tubular glands located almost every part of the skin and are most numerous n the palms and soles. -produce a secretion that is mostly water with a few salts.

GROWTH STAGE OF HAIR- it is formed by the epithelial cells within the hair bulb.

-presence of ducts that open unto the surfaceof the skin through sweat pores

HAIR ROOT AND SHAFT- consists of dead keratinized epithelial cells.

B. APOCRINE SWEAT GLANDS

Resting stage- the growth of hair stops and the hair is held in the hair follicle.

-simple, coiled tubular glands that produce a thick secretion rich in organic substances.

Eyelashes- 30 days.

-open into hair follicles, but only in the axillae and genitalia.

Resting stage: 105 days -become active at puberty. HAIR: 3 years Resting stage:1-2 years

-essentially odourless when released, quickly brokendown by bacteria into substances responsible for what is commonly called body odor.

Pattern baldness- permanent loss of hair in men. Hair color- determined by varying amounts and types of melanin.

NAILS- consisting of layers of dead stratum corneum cells that contain a very hard type of keratin. NAIL BODY-visible part of the nail.

MUSCLES: NAIL ROOT- part of the nail covered by the skin ARRECTOR PILLI- smooth muscle cell that is associated with each hair follicle.

EPONYCHIUM- cuticle; stratum sorneum that extends onto the nail body. HAIR- does does not have a nerve supply. NAIL MATRIX- nail root extends distally NAIL BED- located distal to the nail matrix.

MOVEMENT OF HAIR- can be detected by sensory receptors around the hair follicle

NAIL MATRIX AND BED- epithelial tissue with a stratum basale that gives rise to the cells that form the nail.

VITAMIN D PRODUCTION- exposure of the UV light forms the molecule of vitamin D.

LUNULA- small part of the nail matrix; can be seen through the nail body as a whitish crescent shaped area at the of the nail.

PRECURSOR- CARRIED BY THE BLOOD

PRODUCTION OF CELLS WITHIN THE NAIL MATRIX – results in the growth of the nail. PHYSIOLOGY OF THE INTEGUMENTARY SYSTEM: PROTECTIVE FUNCTIONS: 1. Intact skin- plays an important role in preventing water loss. Lipids-acts as barriers to the diffusion of water. 2.Skin- prevents the entry og microorganisms and other foreign objects into the body. SECRETIONS FROM THE SKIN- produce an environment unsuitable for some microorganism.

Vitamin D- stimulates calcium and phosphate uptake in the intestines. -necessary for normal bone metabolism. TEMPERATURE REGULATION: Blood vessels dilate- (vasodilation) – blood vessel dilation results in increased blood flow toward the surface of the skin. Heat loss across the dermis increases- increased blood flow beneath the epidermis results in increased heat loss. Blood vessel constricts (vasonconstriction)- blood vessel constriction results in decreased blood flow toward the surface of the skin. Heat loss across the epider decreases- decreased blood flow beneath the epidermis results in decreased heat loss.

3.Stratified squamous epithelium- Protects underlying structures against abrasion.

Excretion- removal of waste products from the body

4.Melanin- absorbs UV light and protects underlying structures from its damaging effects.

Cyanosis- bluish color caused by decreased blood oxygen content; indication of impaired circulatory or respiratory function.

5.Hair- protection in several ways: a. hair on the head acts as a heat insulator. b.Eyebrows keep sweat out of the eyes. c.Eyelashes protect the eyes from foreign ob jects. d.Haire.Ears-dust and other materials

Sensation- skin has receptors in the epidermis and dermis that can detect pain, heat and pressure.

Jaundice- due to damage in livers.