ahmad ata 1 integumentary system (skin). 2objectives: 1. name the layers of the skin, describe the...

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Integumentary System Integumentary System (Skin)(Skin)


OBJECTIVES:OBJECTIVES:

1.1. Name the layers of the skin, describe the structure Name the layers of the skin, describe the structure (tissues) of each, and name a general function of each.(tissues) of each, and name a general function of each.

2.2. Discuss the four cell types present in the epidermis..Discuss the four cell types present in the epidermis..

3.3. Explain the protective role of keratin, and in turn, the Explain the protective role of keratin, and in turn, the epidermis.epidermis.

4.4. Name the pigment responsible for skin and hair color, Name the pigment responsible for skin and hair color, and explain how people of different races (i.e. and skin and explain how people of different races (i.e. and skin color) differ in regards to it, and the cell that produces color) differ in regards to it, and the cell that produces it.it.

5.5. List some factors that promote the production of List some factors that promote the production of melanin.melanin.


OBJECTIVES:OBJECTIVES:

7. Describe the structure and function of the 7. Describe the structure and function of the subcutaneous layer.subcutaneous layer.

8. Describe the general structure of a hair follicle 8. Describe the general structure of a hair follicle and identify two other structures that are and identify two other structures that are always associated with them.always associated with them.

9. Distinguish between merocrine (eccrine) and 9. Distinguish between merocrine (eccrine) and apocrine sweat glands in terms of structure, apocrine sweat glands in terms of structure, secretion content and odor, activation, and secretion content and odor, activation, and major body locations.major body locations.

10. Describe the structure, function, secretion, and 10. Describe the structure, function, secretion, and location of sebaceous glands.location of sebaceous glands.

11. Discuss the many functions of skin.11. Discuss the many functions of skin.


IntroductionIntroduction

The integumentary system consists of a The integumentary system consists of a major organ, skin, and many epidermal major organ, skin, and many epidermal derivatives (accessory organs), which derivatives (accessory organs), which include hair follicles, sebaceous glands, include hair follicles, sebaceous glands, sweat glands, and nails.sweat glands, and nails.

The skin is the largest organ in the body and The skin is the largest organ in the body and serves as variety of important function in serves as variety of important function in maintaining health and protect from injurymaintaining health and protect from injury


Integumentary System Integumentary System Includes:Includes:

Skin (cutaneous membrane)Skin (cutaneous membrane) Subcutaneous tissue below Subcutaneous tissue below

the skinthe skin Accessory StructuresAccessory Structures

Sweat glandsSweat glands Sebaceous or oil glandsSebaceous or oil glands HairHair NailsNails


Layers Of The SkinLayers Of The Skin

1.1. Epidermis – outerEpidermis – outera.a. composed of stratified squamous composed of stratified squamous

epitheliumepithelium

2.2. Dermis – innerDermis – inner3.3. subcutaneous layersubcutaneous layer

The fat content of these layers varies The fat content of these layers varies with the state of nutrition, in obese with the state of nutrition, in obese individuals may exceed 10 cm in individuals may exceed 10 cm in thickness.thickness.


THE SKIN


Thin and thick skin Thin and thick skin

Most of the body surface is covered by skin Most of the body surface is covered by skin that is classified as thin.that is classified as thin.

Skin covering the palms of the hand, soles of Skin covering the palms of the hand, soles of the feet are classified as thick.the feet are classified as thick.


Epidermis Epidermis Cell TypesCell Types 1. 1. KeratinocyteKeratinocyte the most important the most important

cell in the epidermis become filled with cell in the epidermis become filled with a tough fibrous protien called keratin.a tough fibrous protien called keratin.

They make up more than 90% of the They make up more than 90% of the epidermal cellsepidermal cells

2. 2. MelanocyteMelanocyte contribute color to the contribute color to the skin and serve to decrease the amount skin and serve to decrease the amount of ultraviolet light that can penetrate of ultraviolet light that can penetrate into deeper layers of the skin.into deeper layers of the skin.


Cell Types:Cell Types:

3. Langerhans cell3. Langerhans cell : : it plays limited role in it plays limited role in immunological reaction that effect the immunological reaction that effect the skin and may serve defense mechanismskin and may serve defense mechanism for the body.for the body.

4. 4. Merkel cellsMerkel cells - - combines with disclike combines with disclike sensory nerve endings to make Merkel’s sensory nerve endings to make Merkel’s discsdiscs


Cell Types:Cell Types:


2) Dermis2) Dermis

It is some time called true skin , it is It is some time called true skin , it is composed of a thin papillary and composed of a thin papillary and thicker reticular layer.thicker reticular layer.

It may exceed 4mm on the soles and It may exceed 4mm on the soles and palms .palms .

At various level in the dermis , there At various level in the dermis , there are muscle fibers, sweet gland, hair are muscle fibers, sweet gland, hair follicles and many blood vessels.follicles and many blood vessels.


Skin color Skin color

The basic determinant of skin color is the The basic determinant of skin color is the quantity of melanin deposit in the cell.quantity of melanin deposit in the cell.

Only melanocytes have ability to convert Only melanocytes have ability to convert amino acid tyrosine in to melanin amino acid tyrosine in to melanin pigments through tyrosinase enzyme.pigments through tyrosinase enzyme.

If the melanocytes cannot formed If the melanocytes cannot formed melanin this condition called albinism melanin this condition called albinism


albinismalbinism

Vitiligo - partial or complete loss of Vitiligo - partial or complete loss of melanin in an areamelanin in an area


Factors effect on skin colorFactors effect on skin color

1.1. Heredity: four to six genes control the Heredity: four to six genes control the amount of melanin formed by melanocytes.amount of melanin formed by melanocytes.

2.2. Prolonged exposure to sunlight Increase Prolonged exposure to sunlight Increase melanin production.melanin production.

3.3. Adenocorticotropic hormones.Adenocorticotropic hormones.4.4. Age Age Modify by:Modify by:1.1. Volume blood in skin capillaries.Volume blood in skin capillaries.2.2. Unoxygenated hemoglobin. Unoxygenated hemoglobin.


Functions of the skinFunctions of the skin

1) Protection:1) Protection: A) from micro organism.A) from micro organism. B) from dehydration.B) from dehydration. C) from ultraviolet.C) from ultraviolet. D) mechanical trauma.D) mechanical trauma. E) painE) pain F) heat and coldF) heat and cold


Functions of the skinFunctions of the skin

2) 2) sensation:sensation: the widespread of the the widespread of the millions of different somatic sensory millions of different somatic sensory receptors that detect stimuli.receptors that detect stimuli.

3) 3) ExcretionExcretion by regulating the volume by regulating the volume and chemical content of sweat.and chemical content of sweat.

4) 4) Vitamin D productionVitamin D production . .5) 5) ImmunityImmunity (langerhan’s cell). (langerhan’s cell).6) Regulation of body temperature. 6) Regulation of body temperature.


Accessory Structures of the Accessory Structures of the SkinSkin

Hair:Hair: Hair is composed of column of dead Hair is composed of column of dead

keratinized.keratinized. Its consists of shaft and root.Its consists of shaft and root. Hair covers the whole body part but its Hair covers the whole body part but its

distribution, color, texture, differ according distribution, color, texture, differ according to:to:

1.1. Location. Location. 2.2. Age .Age .3.3. Gender. Gender.


1) Hair:1) Hair:

Hair color is determined by the amount Hair color is determined by the amount and type of melanin present.and type of melanin present.

Melanocytes become less active with age. Melanocytes become less active with age. Gray hair is a mixture of pigmented and Gray hair is a mixture of pigmented and non-pigmented hairs.non-pigmented hairs.

Red hair results from a a modified type of Red hair results from a a modified type of melanin that contains iron.melanin that contains iron.

AlopeciaAlopecia is the term for hair loss. is the term for hair loss.


Hair Hair

Each hair follicle has an associated Each hair follicle has an associated bundle of smooth muscle, the bundle of smooth muscle, the arrector pili musclearrector pili muscle....


2) Nail :2) Nail :

Nails made of keratin.Nails made of keratin. Parts of nail:Parts of nail: Nail root.Nail root. Nail body.Nail body. Nail bed.Nail bed.

The The lunulalunula is part of the matrix that is part of the matrix that can be seen thru the nail body.can be seen thru the nail body.


Parts of Nail Parts of Nail


Glands of the SkinGlands of the Skin

A) sweet gland are simple coiled tubular glands. A) sweet gland are simple coiled tubular glands. They are divided into two principal types: They are divided into two principal types:

1) Apocrine glands1) Apocrine glands are found mainly in the skin are found mainly in the skin of the armpits, of the genital areas and of the of the armpits, of the genital areas and of the areola of the breasts. Their secretary portion areola of the breasts. Their secretary portion can be located in the dermis or in the can be located in the dermis or in the hypodermis. Their excretory ducts open into hypodermis. Their excretory ducts open into hair follicles. Their secretion is more viscous hair follicles. Their secretion is more viscous than that of the eccrine glands. They start than that of the eccrine glands. They start secreting at puberty.secreting at puberty.



2) Eccrine glands2) Eccrine glands are the most common. are the most common. Their secretory portion can be located in Their secretory portion can be located in the dermis or in the hypodermis. They the dermis or in the hypodermis. They produce sweat, a watery mixture of salts, produce sweat, a watery mixture of salts, antibodies and metabolic wastes. antibodies and metabolic wastes.

Functions in maintaining body Functions in maintaining body temperature, eliminating wastes, and temperature, eliminating wastes, and immunityimmunity



Oil (sebaceous)Oil (sebaceous) Secretes sebum containing fat, salt, Secretes sebum containing fat, salt,

cholesterol and proteincholesterol and protein b. Most are connected to hair follicles, b. Most are connected to hair follicles,

some open directly onto the surface – lips.some open directly onto the surface – lips.

Function - keeps hair from drying, forms a Function - keeps hair from drying, forms a protective film to prevent excess water protective film to prevent excess water evaporation, inhibits bacterial growthevaporation, inhibits bacterial growth



Ceruminous (wax)Ceruminous (wax) - in external - in external auditory meatus; secretes auditory meatus; secretes cerumen (wax) which prevents cerumen (wax) which prevents the entrance of foreign bodies.the entrance of foreign bodies.


Please review chapter 6 page 160Please review chapter 6 page 160

ahmad ata 1 integumentary system (skin). 2objectives: 1. name the layers of the skin, describe the...

Documents

thick skin

skin colorheredity

true skin

functions of skin

epidermis cell types

hair color

production of melanin

important cell