Integumentary Integumentary SystemSystemThe integumentary system, consisting of the The integumentary system, consisting of the

skin, hair and nails, act as a barrier to protect skin, hair and nails, act as a barrier to protect the body from the outside world.  It also the body from the outside world.  It also functions to retain body fluids, protect functions to retain body fluids, protect

against disease, eliminate waste products, against disease, eliminate waste products, receive sensory input, and regulate body receive sensory input, and regulate body

temperature.temperature.

OBJECTIVES:OBJECTIVES: 1. 1. DescribeDescribe the functions of the skin. the functions of the skin. 2. 2. DistinguishDistinguish between the two layers that between the two layers that form the skin. form the skin. 3. 3. IdentifyIdentify two types of glands found in the two types of glands found in the skin, and describe their functions. skin, and describe their functions. 4. 4. DescribeDescribe the structure of nails. the structure of nails. 5. 5. DescribeDescribe the structure of hair. the structure of hair.

1. SKIN AND ITS ACCESSORY ORGANS-THE HAIR, NAILS, 1. SKIN AND ITS ACCESSORY ORGANS-THE HAIR, NAILS, AND A VARIETY OF GLANDS, MAKE UP THE AND A VARIETY OF GLANDS, MAKE UP THE INTEGUMENTARY SYSTEM. INTEGUMENTARY SYSTEM.

2. The 2. The SkinSkin is the human body's largest organs. is the human body's largest organs. 3. The word INTEGUMENT comes from a LATIN word that 3. The word INTEGUMENT comes from a LATIN word that

means to COVER. means to COVER. 4. THE MOST IMPORTANT FUNCTION OF THE 4. THE MOST IMPORTANT FUNCTION OF THE

INTEGUMENTARY SYSTEM IS INTEGUMENTARY SYSTEM IS PROTECTIONPROTECTION. . 5. IT PERFORMS THIS FUNCTION BY: (The SIX Main 5. IT PERFORMS THIS FUNCTION BY: (The SIX Main

Functions of the Integumentary System) Functions of the Integumentary System)         A. SERVING AS A BARRIER AGAINST INFECTION A. SERVING AS A BARRIER AGAINST INFECTION

AND INJURY.AND INJURY.         B. HELPING TO REGULATE BODY TEMPERATURE.B. HELPING TO REGULATE BODY TEMPERATURE.         C. REMOVING WASTE PRODUCTS FROM THE C. REMOVING WASTE PRODUCTS FROM THE

BODY.BODY.         D. PROVIDING PROTECTION AGAINST D. PROVIDING PROTECTION AGAINST

ULTRAVIOLET RADIATION FROM THE SUN.ULTRAVIOLET RADIATION FROM THE SUN.         E.  PRODUCING VITAMIN D.E.  PRODUCING VITAMIN D. F. F. SENSORY RECEPTION.SENSORY RECEPTION.

SkinSkin

6. Because the skin contains several 6. Because the skin contains several types of sensory receptors, it serves types of sensory receptors, it serves as the gateway through which as the gateway through which sensations such as PRESSURE, sensations such as PRESSURE, HEAT, COLD, AND PAIN ARE HEAT, COLD, AND PAIN ARE TRANSMITTED TO THE NERVOUS TRANSMITTED TO THE NERVOUS SYSTEM. SYSTEM.

7.  The skin is composed of two main 7.  The skin is composed of two main layers -layers - The EPIDERMIS and The EPIDERMIS and DERMISDERMIS..

1. The OUTER most layer of skin is known as the 1. The OUTER most layer of skin is known as the EPIDERMISEPIDERMIS.  It is composed of many sheets of flattened, .  It is composed of many sheets of flattened, scaly epithelial cells. This is a thin outer layer of skin. scaly epithelial cells. This is a thin outer layer of skin.

2. Its layers are made of mostly DEAD CELLS. 2. Its layers are made of mostly DEAD CELLS. 3. Most of the cells of the epidermis undergo rapid cell 3. Most of the cells of the epidermis undergo rapid cell

division (MITOSIS). division (MITOSIS). 4. As new cells are produced, they push older cells to the 4. As new cells are produced, they push older cells to the

surface of the skin.  The older cells become flattened, lose surface of the skin.  The older cells become flattened, lose their cellular contents and begin  making their cellular contents and begin  making KERATINKERATIN. .

5. 5. KERATINKERATIN IS A TOUGH FIBROUS PROTEIN AND FORMS IS A TOUGH FIBROUS PROTEIN AND FORMS THE BASIC STRUCTURE OF HAIR, NAILS, AND THE BASIC STRUCTURE OF HAIR, NAILS, AND CALLUSES. CALLUSES.

6. In animals keratin forms cow horns, reptile scales, bird 6. In animals keratin forms cow horns, reptile scales, bird feathers, and porcupine quills. feathers, and porcupine quills.

7. Eventually, the keratin-producing cells (KERATINOCYTES) 7. Eventually, the keratin-producing cells (KERATINOCYTES) DIE AND FORM A TOUGH, FLEXIBLE WATERPROOF DIE AND FORM A TOUGH, FLEXIBLE WATERPROOF COVERING ON THE SURFACE OF THE SKIN.  Our COVERING ON THE SURFACE OF THE SKIN.  Our thickest epidermis in on the palms and soles. thickest epidermis in on the palms and soles.

8. THIS OUTER LAYER OF DEAD CELLS IS SHED OR 8. THIS OUTER LAYER OF DEAD CELLS IS SHED OR WASHED AWAY ONCE EVERY 14 TO 28 DAYS. WASHED AWAY ONCE EVERY 14 TO 28 DAYS.

EpidermisEpidermis

9. The Epidermis contains 9. The Epidermis contains MELANOCYTESMELANOCYTES, CELLS , CELLS THAT PRODUCE THAT PRODUCE MELANINMELANIN, A DARK BROWN , A DARK BROWN PIGMENT. PIGMENT.

10.  BOTH LIGHT SKINNED AND DARK SKINNED 10.  BOTH LIGHT SKINNED AND DARK SKINNED PEOPLE HAVE ROUGHLY THE SAME NUMBER OF PEOPLE HAVE ROUGHLY THE SAME NUMBER OF MELANOCYTES, THE DIFFERENCE IN OUR SKIN MELANOCYTES, THE DIFFERENCE IN OUR SKIN COLOR IS CAUSED BY THE AMOUNT OF MELANIN COLOR IS CAUSED BY THE AMOUNT OF MELANIN THE MELANOCYTES PRODUCE AND DISTRIBUTE. THE MELANOCYTES PRODUCE AND DISTRIBUTE.

11.  The amount of melanin produced in Skin depends 11.  The amount of melanin produced in Skin depends on TWO Factors - Heredity and the Length of Time on TWO Factors - Heredity and the Length of Time the Skin is Exposed to Ultraviolet Radiation the Skin is Exposed to Ultraviolet Radiation (Tanning). (Tanning).

12.  Melanin is important for protection, by absorption 12.  Melanin is important for protection, by absorption of Ultraviolet Radiation from the sun.  All people, but of Ultraviolet Radiation from the sun.  All people, but especially people with Light Skin, need to minimize especially people with Light Skin, need to minimize exposure to the sun and protect themselves from its exposure to the sun and protect themselves from its Ultraviolet Radiation, which can Damage DNA in Skin Ultraviolet Radiation, which can Damage DNA in Skin Cells and lead to deadly forms of Skin Cancer such as Cells and lead to deadly forms of Skin Cancer such as MELANOMA CANCERMELANOMA CANCER. .

13.  THERE ARE NO BLOOD VESSELS IN THE 13.  THERE ARE NO BLOOD VESSELS IN THE EPIDERMIS, WHICH IS WHY A SMALL SCRATCH EPIDERMIS, WHICH IS WHY A SMALL SCRATCH WILL NOT CAUSE BLEEDING.WILL NOT CAUSE BLEEDING.

1. THE 1. THE DERMISDERMIS IS THE INNERMOST THICK IS THE INNERMOST THICK LAYER OF THE SKIN COMPOSED OF LIVING LAYER OF THE SKIN COMPOSED OF LIVING CELLS. IT LIES BENEATH (DEEP TO) THE CELLS. IT LIES BENEATH (DEEP TO) THE EPIDERMIS.EPIDERMIS.

2. The outer (superficial) region of the Dermis 2. The outer (superficial) region of the Dermis consists of areolar connective tissue. This region’s consists of areolar connective tissue. This region’s surface area is greatly increased by the formation surface area is greatly increased by the formation of of DERMAL PAPILLAE,DERMAL PAPILLAE, which project up into the which project up into the epidermis to supply the epidermis with important epidermis to supply the epidermis with important compounds from blood vessels and contain several compounds from blood vessels and contain several different types of sensory receptors. The Dermal different types of sensory receptors. The Dermal Papillae form the Papillae form the EPIDERMAL RIDGESEPIDERMAL RIDGES, which , which form our fingerprints that help us to grip objects. form our fingerprints that help us to grip objects.

3. The inner (deep) region of the Dermis consists of 3. The inner (deep) region of the Dermis consists of dense irregular connective tissue, adipose tissue, dense irregular connective tissue, adipose tissue, BLOOD VESSELS, NERVE ENDINGS, GLANDS, BLOOD VESSELS, NERVE ENDINGS, GLANDS, SENSE ORGANS, SMOOTH MUSCLES, AND SENSE ORGANS, SMOOTH MUSCLES, AND HAIR FOLLICLES. HAIR FOLLICLES.

DermisDermis

4. The Dermis helps us to control our body 4. The Dermis helps us to control our body temperature: temperature:

        A. On a cold day when the body needs to A. On a cold day when the body needs to conserve heat, the Blood Vessels in the Dermis conserve heat, the Blood Vessels in the Dermis NARROW. NARROW.

        B. On hot days, the Blood Vessels WIDEN, B. On hot days, the Blood Vessels WIDEN, warming the skin and increasing heat loss.warming the skin and increasing heat loss.

C. Tiny Muscle fibers called C. Tiny Muscle fibers called ARRECTOR PILIARRECTOR PILI attach to Hair Follicles contract and pull hair attach to Hair Follicles contract and pull hair upright when you are cold or afraid, producing upright when you are cold or afraid, producing what is commonly called Goose Bumps. what is commonly called Goose Bumps.

5. The Dermis contains TWO major types of 5. The Dermis contains TWO major types of GLANDS: GLANDS: SUDERIFEROUS ORSUDERIFEROUS OR SWEAT SWEAT GLANDS AND SEBACEOUS, OR OIL GLANDS AND SEBACEOUS, OR OIL GLANDSGLANDS. .

6. These Glands PASS through the Epidermis 6. These Glands PASS through the Epidermis and RELEASE THEIR PRODUCTS AT THE and RELEASE THEIR PRODUCTS AT THE SURFACE OF THE SKIN. SURFACE OF THE SKIN.

7. 7. SUDERIFEROUS (SWEAT) GLANDSSUDERIFEROUS (SWEAT) GLANDS PRODUCE THE WATERY SECRETIONS PRODUCE THE WATERY SECRETIONS KNOWN AS KNOWN AS PERSPERATION OR SWEATPERSPERATION OR SWEAT, , WHICH CONTAINS SALT, WATER, AND WHICH CONTAINS SALT, WATER, AND OTHER COMPOUNDS. OTHER COMPOUNDS.

8. These secretions are stimulated by nerve 8. These secretions are stimulated by nerve impulses that cause the production of sweat impulses that cause the production of sweat when the temperature of the body is raised.  when the temperature of the body is raised.  They help to cool the body.They help to cool the body.

9. 9. SEBACEOUS GLANDSSEBACEOUS GLANDS, (OIL GLANDS) , (OIL GLANDS) PRODUCE OILY SECRETION KNOWN AS PRODUCE OILY SECRETION KNOWN AS SEBUMSEBUM THAT SPREADS OUT ALONG THE THAT SPREADS OUT ALONG THE SURFACE OF THE SKIN AND KEEPS THE SURFACE OF THE SKIN AND KEEPS THE KERATIN RICH EPIDERMIS FLEXIBLE AND KERATIN RICH EPIDERMIS FLEXIBLE AND WATERPROOF. WATERPROOF.

10. The production of Sebum is controlled by 10. The production of Sebum is controlled by Hormones. Hormones.

11. Oil Glands are usually connected by Tiny 11. Oil Glands are usually connected by Tiny Ducts (Exocrine Glands) to Hair Follicles.  Ducts (Exocrine Glands) to Hair Follicles.  Sebum coats the surface of the skin and the Sebum coats the surface of the skin and the shafts of hair, preventing excess water loss shafts of hair, preventing excess water loss and lubricating and softening the Skin and and lubricating and softening the Skin and Hair. Hair.

12. Sebum is mildly toxic to some Bacteria - 12. Sebum is mildly toxic to some Bacteria - protection. protection.

13. If the Ducts of Oil Glands become clogged 13. If the Ducts of Oil Glands become clogged with excessive amounts of Sebum, Dead Cells, with excessive amounts of Sebum, Dead Cells, and Bacteria, the Skin disorder and Bacteria, the Skin disorder ACNEACNE can can result. result.

14. Other glands in the dermis include 14. Other glands in the dermis include CERUMINOUS GLANDSCERUMINOUS GLANDS and and MAMMARY GLANDS.MAMMARY GLANDS.

CERUMINOUS GLANDSCERUMINOUS GLANDS produce and a produce and a waxy secretion known as waxy secretion known as CERUMENCERUMEN and and are found in the outer ear canal. Cerumen are found in the outer ear canal. Cerumen and hair form a sticky barrier to foreign and hair form a sticky barrier to foreign invaders.invaders.

MAMMARY GLANDSMAMMARY GLANDS are modified are modified suderiferous glands that produce milk in suderiferous glands that produce milk in nursing (lactating) mothers. The nursing (lactating) mothers. The production and ejection of milk is production and ejection of milk is controlled by hormones.controlled by hormones.

HypodermisHypodermis

Beneath the Dermis is the Beneath the Dermis is the HYPODERMISHYPODERMIS, OR , OR SUBCUTANEOUS SUBCUTANEOUS LAYER (SUB Q)LAYER (SUB Q), A LAYER OF ADIPOSE , A LAYER OF ADIPOSE AND AREOLAR CONNECTIVE TISSUE AND AREOLAR CONNECTIVE TISSUE THAT CONNECTS THE SKIN TO THE THAT CONNECTS THE SKIN TO THE UNDERLYING MUSCLES AND BONES. UNDERLYING MUSCLES AND BONES. IT INSULATES THE BODY AND ACTS IT INSULATES THE BODY AND ACTS AS AN ENERGY RESERVE. The AS AN ENERGY RESERVE. The Hypodermis also contains the large Hypodermis also contains the large blood vessels that supply the skin.blood vessels that supply the skin.

Hair and NailsHair and Nails

1. 1. HAIRHAIR IS PRODUCED BY CELLS AT THE BASE OF IS PRODUCED BY CELLS AT THE BASE OF STRUCTURES CALLED STRUCTURES CALLED HAIR FOLLICLESHAIR FOLLICLES. (Figure . (Figure 45-15) 45-15)

2. Hair Follicles are tubelike pockets of Epidermal Cells 2. Hair Follicles are tubelike pockets of Epidermal Cells that extend into the Dermis. that extend into the Dermis.

3. Individual hairs are actually large columns of  DEAD 3. Individual hairs are actually large columns of  DEAD Cells that have filled with Cells that have filled with KERATIN.KERATIN.. .

4. Rapid cell growth at the base of the Hair Follicle in 4. Rapid cell growth at the base of the Hair Follicle in the the HAIR ROOTHAIR ROOT causes hair to grow longer.  Hair causes hair to grow longer.  Hair gets its color from gets its color from MelaninMelanin. .

5. Hair Follicles are in close contact with Sebaceous 5. Hair Follicles are in close contact with Sebaceous Glands.  The oily secretions of these Glands help Glands.  The oily secretions of these Glands help maintain the condition of each individual hair. maintain the condition of each individual hair.

6. Hair protects and insulates the body. 6. Hair protects and insulates the body. 7. Most individual hairs grow for several years and then 7. Most individual hairs grow for several years and then

fall out.fall out.

8. 8. NAILSNAILS GROW FROM AN AREA OF GROW FROM AN AREA OF RAPIDLY DIVIDING CELLS KNOWN AS RAPIDLY DIVIDING CELLS KNOWN AS THE THE NAIL MATRIX or NAIL ROOTNAIL MATRIX or NAIL ROOT. .

9. THE 9. THE NAIL MATRIXNAIL MATRIX IS LOCATED NEAR IS LOCATED NEAR THE TIPS OF THE FINGERS AND TOES. THE TIPS OF THE FINGERS AND TOES.

10. During Cell division, the Cells fill with 10. During Cell division, the Cells fill with KeratinKeratin and produce a tough, strong and produce a tough, strong platelike nail that covers and Protects the platelike nail that covers and Protects the tips of the fingers and toes. tips of the fingers and toes.

11. Nails rest on a Bed of tissue filled with 11. Nails rest on a Bed of tissue filled with Blood Vessels, giving the nails a Pinkish Blood Vessels, giving the nails a Pinkish Color. Color.

12. Nails grow at a rate of 0.5 to 1.2 mm 12. Nails grow at a rate of 0.5 to 1.2 mm per day, with fingernails growing faster per day, with fingernails growing faster than toenails. than toenails.