A&P 1 Ch 5 Integumentary System lecture notes

Anatomy and Physiology I- Chapter 5 Integumentary System Anatomy and Physiology I- Chapter 5 – Chapter Objectives 2 Anatomy and Physiology I- Chapter 5 - Integumentary System Skin Functions: 1.     Protects tissue and organs from shock 2.     Excretes salts, water, wastes 3.     Maintenance of body temperature 4.     Makes vitamin D3 (a steroid) which is converted to calcitriol Storage of nutrients – lipids stored in adipocytes in dermis and subcutaneous layer   Chapter 5 - Integumentary System Two Major Parts of Integumentary System: 1.  Cutaneous Membrane -Epidermis – (“epi” means above) epithelia; does NOT have blood vessels; consists of stratified squamous -Dermis – under laying area of connective tissue; has a lot of blood vessels, epidermis doesn’t; consists of dense irregular -Another layer, deeper than dermis is called “subcutaneous layer” also called “hypodermis”. NOT part of cutaneous membrane   2. Accessories -Hair, nails, 4 types of exocrine glands    Keratinocytes – body’s most abundant epithelial cells; Types of Skin Layering  A. Thick skin – Five layers palms of hands and soles of feet: stratum germinativum (deepest) stratum spinosum stratum granulosum stratum lucidum (not found in thin skin) stratum corneum Thin skin – Four layers cover rest of body; 1. stratum germinativum (deepest) 2. stratum spinosum 3. stratum granulosum 4. stratum corneum   Epidermal Skin Layers: (Stratum means one layer; Strata means two + layers) 1). Stratum germinativum (stratum basal) – This is the deepest layer and is attached to the basal lamina. - About 1 cell layer thick. -Basal lamina separates epithelia from connective tissue. -Has epidermal ridges which extends into dermis which increases contact area between two places increasing attachment strength. -Germinativum Cells, also called basal cells, are found throughout stratum germinativum and are “stem cells” which replace the cells lost in the upper layers -Merkel Cells are sensitive to touch (pain receptors); when compressed by pressure they release chemicals that stimulate nerves. -Melanocytes produce brown pigment and are found here.       Pigments and Skin Color: -Carotene is orange/ yellow pigment in epidermis. -Comes from carrots and squash and is converted to vitamin A (important to eyes and epithelia)   -Melanin – is a brown, yellow brown or black pigment produced by melanocytes in epidermis. Albinos lack melanin. -Melanocytes are located in Stratum Germinativum and make melanin from AA tyrosine. -Protects against UV radiation (sun light) UV damages DNA causes skin cancers like malignant cancer` and melanoma. -Melanin concentration increases in response to sunlight Dermal Circulation and Color: -Hemoglobin (transports oxygen) looks red when attached to O2 -When hemoglobin is attached to CO2 vessels look blue   -When blood supply in dermis is reduced the skin becomes “pale”. -Jaundice – Liver unable to excrete bile so yellow pigment accumulates in body causing skin and eyes to turn yellow; occurs in newborns and can be easily cured by placing under a UV lamp.   Epidermal Skin Layers (cont.): 2). Stratum Spinosum – Each time one stem cell divides into two daughter cells, the daughter cell is pushed from stratum germinativum to stratum Spinosum. -Have 8 - 10 layers of cells -LangerHans cells (involved in immune response) are found in this layer and they: a. defend against microorganisms that penetrate skin b. attack superficial skin cancers   Epidermal Skin Layers (cont.): 3). Stratum Granulosum –(Also called “grainy layer”); this strata has 3-5 layers of keratinocytes. -When cells reach this layer they have quit dividing and start to make proteins keratin. These proteins are found in hair/nails.   4). Stratum Lucidum (Also called “Clear layer”) – Found only in thick skin of palms of hands and soles of feet. -Cells are flattened, densely packed and filled w/ keratin. Epidermal Skin Layers (cont.): 5). Stratum Corneum – Constitues the exposed areas of both thick and thin skin. Most superficial layer. -15 - 30 layers of keratinized cells. -Keratinization or “cornification” is the formation of a protective layer of cells w/ keratin. -It takes 15 - 30 days from cell to move from Stratum Germinativum to Stratum Corneum. -Dead cells remain on top of Stratum Corneum for two more weeks until pushed to skin surface and lost. Epidermal Skin Layers (cont.): -Stratum Corneum is H2O resistant but not H2O proof -500ml H2O lost by evaporation each day through skin. (insensible perspiration) -Sensible perspiration is produced by sweat glands. -Extreme Sunlight can damage skin, but is needed for Stratum Spinosum and Stratum Germinativum so they can convert a steroid into vitamin D3 (also called cholecalciferol). -Liver then converts D3 into an intermediary product used by the Kidney to to make calcitriol which is needed for calcium absorption and bone growth. This is why they put Vitamin D in milk because a lot of people do not get out in the sunlight enough to produce D3. Epidermal Growth Factor: – made in salivary glands; This hormone induces cells in epidermis to grow. Functions: Promotes division of cells in Stratum Germinativum and Stratum Spinosum 2. Accelerates Keratin production 3. Stimulates epidermal repair after injury Skin Cancers: Basal cell carcinoma – malignant cancer found in Stratum Germinativum (Most common form of cancer) due to UV radiation.   Dermis: (consists of two layers) 1). Papillary layer (superficial); consists of areola tissue and contains capillaries and sensory neurons. 2). Reticular layer (deeper layer); consists of dense irregular tissue. -Accessory Organs (hair, sweat glands) extend into dermis. -Dermis also has blood vessels, lymph vessels, and nerve fibers. -Dermatitis is inflammation of the skin primarily in the papillary layer due to chemicals or radiation. Dermal Circulation and Nerve Supply: -If blood supply gets interrupted to the epidermis or dermis you can get an ulcer (shedding of epithelium) -Bed sores or “decubitis ulcers” affect bed ridden people by killing epidermal cells and then removes the barrier to infection by bacteria. -Nerve cells (merkel cells) are located here so bed sores affect these cells, sending intense pain stimuli to CNS.   Dermal Circulation and Nerve Supply (cont.): Subcutaneous layer – NOT part of integumentary system -Contains areola and adipose tissue -has substantial number of blood vessels therefore good place for injections with hypodermic needles. -This is the location of liposuction to remove adipocytes. Accessory Organs: Hair -Hair shaft is a protein (NO DNA) and are made by “hair follicles”. -Hair root – anchors hair to skin *Figure 5:9 -Hair Shaft – part of hair we see on surface -Cuticle – outer surface of the shaft and covers the “cortex” -Hair papilla – a piece of connective tissue containing capillaries and nerves -Hair color comes from pigments “melanin”; with age pigment production decreases causing hair to become gray   Hair Types: Embryo Lanugos – Hairs formed after 3 months on embryo then are shed before birth Adult 1.  vellus hairs – “peach fuzz” covers body surface 2. terminal hairs – on head, eyebrows, eyelashes Hair Functions: -Root hair plexus – nerves surround the base so you can feel wind blow -Arrector pili – muscle that causes hair to stand up due to fear, rage, cold and emotional states   Accessory Organs: Glands in the Skin Two types of Exocrine Glands in skin (secretes into ducts) 1.  Sebaceous (also called Oil glands or holocrine glands) – produce oily lipid that coats hair. -Liquid released through rupture of the secretory cells and inhibits bacteria. A. Sebaceous glands- release onto hairs B. Sebaceous follicles- release onto the skin Accessory Organs: Glands in the Skin (cont.) 2.  Sweat Glands (cont.): – also called “sudoriferous glands” Two Subtypes: -Apocrine – arm pits and groin secrete their products onto hair follicles. -Bacteria use the sweat as a nutrient source which in turn produces an odor -Merocrine Glands – more numerous than aprocrine glands, secrete their products onto the surface of the skin. Found all over the body and in the palms of hands and soles of feet. Accessory Organs: Glands in the Skin (cont.) -Sweat produced by merocrine glands is called sensible perspiration which: a. cools the body, causes body temperature to decrease b. excretes salts, drugs c. protects against bacteria Other Glands: 1.  Mammary glands – produce milk 2.  Ceruminous glands – modified sweat glands in ears, secretions combines with secretions from sebaceous glands nearby to form wax (“cerumen”) Accessory Organs: Nails -nail body- covers area known as “nail bed” -nail folds – on each side of the nail -nail root – where growth starts -eponychium – portion of “stratum corneum” extends over nail at nail root (also called the cuticle) -Blood vessels – may be obscured near cuticle and make lunula “moon”         Repair of Skin due to injury: Incision – cut Abrasion – scrape Step one – Injury (cut or scrape) to skin causes bleeding to occur, blood clots to stop bleeding, mast cells detect injury and trigger an immune response. Step two – Scab formed over injury, cells from Stratum Germinativum move into area. Blood flow to region increases bringing more phagocytic cells. Step three – Scab undermined by epidermal cells to start repair; fibroblasts produce meshwork of “fibers” over top of injury creating scar tissue Step four – Scab disappears, fibroblasts continue to create scar tissue that will raise the overlapping epidermis higher than original skin. Repair of Skin due to injury (cont.): - Granulation tissue – combination of blood clot, fibroblasts, capillary network - Keloid – thickened area of scar tissue which has a shiny surface Aging: -Epidermis thins -number of langerhans cells decrease -D3 production drops -number of melanocytes decrease -gland activity reduces -blood supply to skin decreases -Collagen decreases making skin thinner and weaker -Elastin decreases making skin less tight more wrinkled -Moisture decreases making skin drier Medical conditions of the Integumentary System -Nails become yellow if have AIDS or thyroid gland problems -Psoriasis – rapid cell division of stem cells in Stratum Germinativum Diseases/conditions: -Albinism- results from genetic defect that prevents the amino acid tyrosine from being made; therefore the protein melanin cannot be produced causing the skin to have a white color. -psoriasis- stratum germinativum becomes highly active causing cells to divide every day (normally they divide one time every twenty days). Occurs on scalp, elbows, palms, soles of feet. Can be aggravated by stress or anxiety; no known cure but normally painless. -Microbial infections: -viral- fever blisters, genital herpes, chicken pox, shingles, warts -Bacterial- boils, impetigo, leprosy -Leprosy (Hansen’s disease) caused by a bacteria which destroys nerve endings thus the person cannot detect extreme heat/cold in hands. -fungal-ringworm, athletes foot, candidiasis -parasitic-scabies, swimmers itch Biol 2010 – A&P I Study Questions for Ch. 5 1. What constitutes the integumentary system? What are the major functions of the integumentary system? 2. Discuss the methods of heat transfer. Contrast sensible and insensible perspiration. Why do we sweat? What is sweat? Contrast merocrine and apocrine sweat glands and their products. What are sebaceous glands? What are cerumenous and mammary glands? 3. What types of pigments are found in the skin? What is the function of pigment? 4. What are the layers of the epidermis? Give the characteristics of each of the layers. How do thick and thin skin differ? What type of tissue and types of cells are found in the epidermis? 5. Describe the dermis and hypodermis. What types of tissue are here? Contrast the papillary and reticular layers. Give other terms for the hypodermis. 6. Describe hair and the associated structures. What is the function of hair? 7. Describe nails. Describe the growth of nails and compare it to the growth of hair. Define cutaneous membrane melanocytes Rickets osteoporosis keratin Epidermal ridges papillary layer reticular layer Elastic fibers collagen hair follicl Hair root hair shaft hair papilla Arrector pili muscle sebaceous gland nail root Nail bed nail body nail fold hyponychium eponychium Lunula Anatomy and Physiology I- Chapter 5 – Chapter Objectives 1 List functions and characteristics of the skin. Discuss types of cells and tissues found in the skin. Describe the structure and function of the three layers of the skin. Describe the accessory structures (hair, nails and glands) associated with the skin, along with the functions of each. Explain how the skin functions in regulating body temperature. 6. Discuss sense of touch and receptors involved. 7. Discuss common disorders of the skin. 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What concepts are you having the most problem with in this chapter or would like more information about? Anatomy and Physiology I- Chapter 5 Integumentary System Anatomy and Physiology I- Chapter 5 – Chapter Objectives 2 Anatomy and Physiology I- Chapter 5 - Integumentary System Skin Functions: 1.     Protects tissue and organs from shock 2.     Excretes salts, water, wastes 3.     Maintenance of body temperature 4.     Makes vitamin D3 (a steroid) which is converted to calcitriol Storage of nutrients – lipids stored in adipocytes in dermis and subcutaneous layer   Chapter 5 - Integumentary System Two Major Parts of Integumentary System: 1.  Cutaneous Membrane -Epidermis – (“epi” means above) epithelia; does NOT have blood vessels; consists of stratified squamous -Dermis – under laying area of connective tissue; has a lot of blood vessels, epidermis doesn’t; consists of dense irregular -Another layer, deeper than dermis is called “subcutaneous layer” also called “hypodermis”. NOT part of cutaneous membrane   2. Accessories -Hair, nails, 4 types of exocrine glands    Keratinocytes – body’s most abundant epithelial cells; Types of Skin Layering  A. Thick skin – Five layers palms of hands and soles of feet: stratum germinativum (deepest) stratum spinosum stratum granulosum stratum lucidum (not found in thin skin) stratum corneum Thin skin – Four layers cover rest of body; 1. stratum germinativum (deepest) 2. stratum spinosum 3. stratum granulosum 4. stratum corneum   Epidermal Skin Layers: (Stratum means one layer; Strata means two + layers) 1). Stratum germinativum (stratum basal) – This is the deepest layer and is attached to the basal lamina. - About 1 cell layer thick. -Basal lamina separates epithelia from connective tissue. -Has epidermal ridges which extends into dermis which increases contact area between two places increasing attachment strength. -Germinativum Cells, also called basal cells, are found throughout stratum germinativum and are “stem cells” which replace the cells lost in the upper layers -Merkel Cells are sensitive to touch (pain receptors); when compressed by pressure they release chemicals that stimulate nerves. -Melanocytes produce brown pigment and are found here.       Pigments and Skin Color: -Carotene is orange/ yellow pigment in epidermis. -Comes from carrots and squash and is converted to vitamin A (important to eyes and epithelia)   -Melanin – is a brown, yellow brown or black pigment produced by melanocytes in epidermis. Albinos lack melanin. -Melanocytes are located in Stratum Germinativum and make melanin from AA tyrosine. -Protects against UV radiation (sun light) UV damages DNA causes skin cancers like malignant cancer` and melanoma. -Melanin concentration increases in response to sunlight Dermal Circulation and Color: -Hemoglobin (transports oxygen) looks red when attached to O2 -When hemoglobin is attached to CO2 vessels look blue   -When blood supply in dermis is reduced the skin becomes “pale”. -Jaundice – Liver unable to excrete bile so yellow pigment accumulates in body causing skin and eyes to turn yellow; occurs in newborns and can be easily cured by placing under a UV lamp.   Epidermal Skin Layers (cont.): 2). Stratum Spinosum – Each time one stem cell divides into two daughter cells, the daughter cell is pushed from stratum germinativum to stratum Spinosum. -Have 8 - 10 layers of cells -LangerHans cells (involved in immune response) are found in this layer and they: a. defend against microorganisms that penetrate skin b. attack superficial skin cancers   Epidermal Skin Layers (cont.): 3). Stratum Granulosum –(Also called “grainy layer”); this strata has 3-5 layers of keratinocytes. -When cells reach this layer they have quit dividing and start to make proteins keratin. These proteins are found in hair/nails.   4). Stratum Lucidum (Also called “Clear layer”) – Found only in thick skin of palms of hands and soles of feet. -Cells are flattened, densely packed and filled w/ keratin. Epidermal Skin Layers (cont.): 5). Stratum Corneum – Constitues the exposed areas of both thick and thin skin. Most superficial layer. -15 - 30 layers of keratinized cells. -Keratinization or “cornification” is the formation of a protective layer of cells w/ keratin. -It takes 15 - 30 days from cell to move from Stratum Germinativum to Stratum Corneum. -Dead cells remain on top of Stratum Corneum for two more weeks until pushed to skin surface and lost. Epidermal Skin Layers (cont.): -Stratum Corneum is H2O resistant but not H2O proof -500ml H2O lost by evaporation each day through skin. (insensible perspiration) -Sensible perspiration is produced by sweat glands. -Extreme Sunlight can damage skin, but is needed for Stratum Spinosum and Stratum Germinativum so they can convert a steroid into vitamin D3 (also called cholecalciferol). -Liver then converts D3 into an intermediary product used by the Kidney to to make calcitriol which is needed for calcium absorption and bone growth. This is why they put Vitamin D in milk because a lot of people do not get out in the sunlight enough to produce D3. Epidermal Growth Factor: – made in salivary glands; This hormone induces cells in epidermis to grow. Functions: Promotes division of cells in Stratum Germinativum and Stratum Spinosum 2. Accelerates Keratin production 3. Stimulates epidermal repair after injury Skin Cancers: Basal cell carcinoma – malignant cancer found in Stratum Germinativum (Most common form of cancer) due to UV radiation.   Dermis: (consists of two layers) 1). Papillary layer (superficial); consists of areola tissue and contains capillaries and sensory neurons. 2). Reticular layer (deeper layer); consists of dense irregular tissue. -Accessory Organs (hair, sweat glands) extend into dermis. -Dermis also has blood vessels, lymph vessels, and nerve fibers. -Dermatitis is inflammation of the skin primarily in the papillary layer due to chemicals or radiation. Dermal Circulation and Nerve Supply: -If blood supply gets interrupted to the epidermis or dermis you can get an ulcer (shedding of epithelium) -Bed sores or “decubitis ulcers” affect bed ridden people by killing epidermal cells and then removes the barrier to infection by bacteria. -Nerve cells (merkel cells) are located here so bed sores affect these cells, sending intense pain stimuli to CNS.   Dermal Circulation and Nerve Supply (cont.): Subcutaneous layer – NOT part of integumentary system -Contains areola and adipose tissue -has substantial number of blood vessels therefore good place for injections with hypodermic needles. -This is the location of liposuction to remove adipocytes. Accessory Organs: Hair -Hair shaft is a protein (NO DNA) and are made by “hair follicles”. -Hair root – anchors hair to skin *Figure 5:9 -Hair Shaft – part of hair we see on surface -Cuticle – outer surface of the shaft and covers the “cortex” -Hair papilla – a piece of connective tissue containing capillaries and nerves -Hair color comes from pigments “melanin”; with age pigment production decreases causing hair to become gray   Hair Types: Embryo Lanugos – Hairs formed after 3 months on embryo then are shed before birth Adult 1.  vellus hairs – “peach fuzz” covers body surface 2. terminal hairs – on head, eyebrows, eyelashes Hair Functions: -Root hair plexus – nerves surround the base so you can feel wind blow -Arrector pili – muscle that causes hair to stand up due to fear, rage, cold and emotional states   Accessory Organs: Glands in the Skin Two types of Exocrine Glands in skin (secretes into ducts) 1.  Sebaceous (also called Oil glands or holocrine glands) – produce oily lipid that coats hair. -Liquid released through rupture of the secretory cells and inhibits bacteria. A. Sebaceous glands- release onto hairs B. Sebaceous follicles- release onto the skin Accessory Organs: Glands in the Skin (cont.) 2.  Sweat Glands (cont.): – also called “sudoriferous glands” Two Subtypes: -Apocrine – arm pits and groin secrete their products onto hair follicles. -Bacteria use the sweat as a nutrient source which in turn produces an odor -Merocrine Glands – more numerous than aprocrine glands, secrete their products onto the surface of the skin. Found all over the body and in the palms of hands and soles of feet. Accessory Organs: Glands in the Skin (cont.) -Sweat produced by merocrine glands is called sensible perspiration which: a. cools the body, causes body temperature to decrease b. excretes salts, drugs c. protects against bacteria Other Glands: 1.  Mammary glands – produce milk 2.  Ceruminous glands – modified sweat glands in ears, secretions combines with secretions from sebaceous glands nearby to form wax (“cerumen”) Accessory Organs: Nails -nail body- covers area known as “nail bed” -nail folds – on each side of the nail -nail root – where growth starts -eponychium – portion of “stratum corneum” extends over nail at nail root (also called the cuticle) -Blood vessels – may be obscured near cuticle and make lunula “moon”         Repair of Skin due to injury: Incision – cut Abrasion – scrape Step one – Injury (cut or scrape) to skin causes bleeding to occur, blood clots to stop bleeding, mast cells detect injury and trigger an immune response. Step two – Scab formed over injury, cells from Stratum Germinativum move into area. Blood flow to region increases bringing more phagocytic cells. Step three – Scab undermined by epidermal cells to start repair; fibroblasts produce meshwork of “fibers” over top of injury creating scar tissue Step four – Scab disappears, fibroblasts continue to create scar tissue that will raise the overlapping epidermis higher than original skin. Repair of Skin due to injury (cont.): - Granulation tissue – combination of blood clot, fibroblasts, capillary network - Keloid – thickened area of scar tissue which has a shiny surface Aging: -Epidermis thins -number of langerhans cells decrease -D3 production drops -number of melanocytes decrease -gland activity reduces -blood supply to skin decreases -Collagen decreases making skin thinner and weaker -Elastin decreases making skin less tight more wrinkled -Moisture decreases making skin drier Medical conditions of the Integumentary System -Nails become yellow if have AIDS or thyroid gland problems -Psoriasis – rapid cell division of stem cells in Stratum Germinativum Diseases/conditions: -Albinism- results from genetic defect that prevents the amino acid tyrosine from being made; therefore the protein melanin cannot be produced causing the skin to have a white color. -psoriasis- stratum germinativum becomes highly active causing cells to divide every day (normally they divide one time every twenty days). Occurs on scalp, elbows, palms, soles of feet. Can be aggravated by stress or anxiety; no known cure but normally painless. -Microbial infections: -viral- fever blisters, genital herpes, chicken pox, shingles, warts -Bacterial- boils, impetigo, leprosy -Leprosy (Hansen’s disease) caused by a bacteria which destroys nerve endings thus the person cannot detect extreme heat/cold in hands. -fungal-ringworm, athletes foot, candidiasis -parasitic-scabies, swimmers itch Biol 2010 – A&P I Study Questions for Ch. 5 1. What constitutes the integumentary system? What are the major functions of the integumentary system? 2. Discuss the methods of heat transfer. Contrast sensible and insensible perspiration. Why do we sweat? What is sweat? Contrast merocrine and apocrine sweat glands and their products. What are sebaceous glands? What are cerumenous and mammary glands? 3. What types of pigments are found in the skin? What is the function of pigment? 4. What are the layers of the epidermis? Give the characteristics of each of the layers. How do thick and thin skin differ? What type of tissue and types of cells are found in the epidermis? 5. Describe the dermis and hypodermis. What types of tissue are here? Contrast the papillary and reticular layers. Give other terms for the hypodermis. 6. Describe hair and the associated structures. What is the function of hair? 7. Describe nails. Describe the growth of nails and compare it to the growth of hair. Define cutaneous membrane melanocytes Rickets osteoporosis keratin Epidermal ridges papillary layer reticular layer Elastic fibers collagen hair follicl Hair root hair shaft hair papilla Arrector pili muscle sebaceous gland nail root Nail bed nail body nail fold hyponychium eponychium Lunula Anatomy and Physiology I- Chapter 5 – Chapter Objectives 1 List functions and characteristics of the skin. Discuss types of cells and tissues found in the skin. Describe the structure and function of the three layers of the skin. Describe the accessory structures (hair, nails and glands) associated with the skin, along with the functions of each. Explain how the skin functions in regulating body temperature. 6. Discuss sense of touch and receptors involved. 7. Discuss common disorders of the skin. Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Repair of Skin due to injury Chapter 5 - Integumentary System Repair of Skin due to injury Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System One Minute Paper What did you like the most in this chapter? What concepts are you having the most problem with in this chapter or would like more information about? Anatomy and Physiology I- Chapter 5 Integumentary System Anatomy and Physiology I- Chapter 5 – Chapter Objectives 2 Anatomy and Physiology I- Chapter 5 - Integumentary System Skin Functions: 1.    Protects tissue and organs from shock 2.     Excretes salts, water, wastes 3.     Maintenance of body temperature 4.     Makes vitamin D3 (a steroid) which is converted to calcitriol Storage of nutrients – lipids stored in adipocytes in dermis and subcutaneous layer   Chapter 5 - Integumentary System Two Major Parts of Integumentary System: 1.  Cutaneous Membrane -Epidermis – (“epi” means above) epithelia; does NOT have blood vessels; consists of stratified squamous -Dermis – under laying area of connective tissue; has a lot of blood vessels, epidermis doesn’t; consists of dense irregular -Another layer, deeper than dermis is called “subcutaneous layer” also called “hypodermis”. NOT part of cutaneous membrane   2. Accessories -Hair, nails, 4 types of exocrine glands    Keratinocytes – body’s most abundant epithelial cells; Types of Skin Layering  A. Thick skin – Five layers palms of hands and soles of feet: stratum germinativum (deepest) stratum spinosum stratum granulosum stratum lucidum (not found in thin skin) stratum corneum Thin skin – Four layers cover rest of body; 1. stratum germinativum (deepest) 2. stratum spinosum 3. stratum granulosum 4. stratum corneum     Epidermal Skin Layers: (Stratum means one layer; Strata means two + layers) 1). Stratum germinativum (stratum basal) – This is the deepest layer and is attached to the basal lamina. - About 1 cell layer thick. -Basal lamina separates epithelia from connective tissue. -Has epidermal ridges which extends into dermis which increases contact area between two places increasing attachment strength. -Germinativum Cells, also called basal cells, are found throughout stratum germinativum and are “stem cells” which replace the cells lost in the upper layers -Merkel Cells are sensitive to touch (pain receptors); when compressed by pressure they release chemicals that stimulate nerves. -Melanocytes produce brown pigment and are found here. Dermal Circulation and Color: -Hemoglobin (transports oxygen) looks red when attached to O2 -When hemoglobin is attached to CO2 vessels look blue   -When blood supply in dermis is reduced the skin becomes “pale”. -Jaundice – Liver unable to excrete bile so yellow pigment accumulates in body causing skin and eyes to turn yellow; occurs in newborns and can be easily cured by placing under a UV lamp.   Epidermal Skin Layers (cont.): 2). Stratum Spinosum – Each time one stem cell divides into two daughter cells, the daughter cell is pushed from stratum germinativum to stratum Spinosum. -Have 8 - 10 layers of cells -LangerHans cells (involved in immune response) are found in this layer and they: a. defend against microorganisms that penetrate skin b. attack superficial skin cancers   Epidermal Skin Layers (cont.): 3). Stratum Granulosum –(Also called “grainy layer”); this strata has 3-5 layers of keratinocytes. -When cells reach this layer they have quit dividing and start to make proteins keratin. These proteins are found in hair/nails.   4). Stratum Lucidum (Also called “Clear layer”) – Found only in thick skin of palms of hands and soles of feet. -Cells are flattened, densely packed and filled w/ keratin. Epidermal Skin Layers (cont.): 5). Stratum Corneum – Constitues the exposed areas of both thick and thin skin. Most superficial layer. -15 - 30 layers of keratinized cells. -Keratinization or “cornification” is the formation of a protective layer of cells w/ keratin. -It takes 15 - 30 days from cell to move from Stratum Germinativum to Stratum Corneum. -Dead cells remain on top of Stratum Corneum for two more weeks until pushed to skin surface and lost. Epidermal Skin Layers (cont.): -Stratum Corneum is H2O resistant but not H2O proof -500ml H2O lost by evaporation each day through skin. (insensible perspiration) -Sensible perspiration is produced by sweat glands. -Extreme Sunlight can damage skin, but is needed for Stratum Spinosum and Stratum Germinativum so they can convert a steroid into vitamin D3 (also called cholecalciferol). -Liver then converts D3 into an intermediary product used by the Kidney to to make calcitriol which is needed for calcium absorption and bone growth. This is why they put Vitamin D in milk because a lot of people do not get out in the sunlight enough to produce D3.     Pigments and Skin Color: -Carotene is orange/ yellow pigment in epidermis. -Comes from carrots and squash and is converted to vitamin A (important to eyes and epithelia)   -Melanin – is a brown, yellow brown or black pigment produced by melanocytes in epidermis. Albinos lack melanin. -Melanocytes are located in Stratum Germinativum and make melanin from AA tyrosine. -Protects against UV radiation (sun light) UV damages DNA causes skin cancers like malignant cancer` and melanoma. -Melanin concentration increases in response to sunlight Epidermal Growth Factor: – made in salivary glands; This hormone induces cells in epidermis to grow. Functions: Promotes division of cells in Stratum Germinativum and Stratum Spinosum 2. Accelerates Keratin production 3. Stimulates epidermal repair after injury Skin Cancers: Basal cell carcinoma – malignant cancer found in Stratum Germinativum (Most common form of cancer) due to UV radiation.   Dermis: (consists of two layers) 1). Papillary layer (superficial); consists of areolar tissue and contains capillaries and sensory neurons. 2). Reticular layer (deeper layer); consists of dense irregular tissue. -Accessory Organs (hair, sweat glands) extend into dermis. -Dermis also has blood vessels, lymph vessels, and nerve fibers. -Dermatitis is inflammation of the skin primarily in the papillary layer due to chemicals or radiation. Dermal Circulation and Nerve Supply: -If blood supply gets interrupted to the epidermis or dermis you can get an ulcer (shedding of epithelium) -Bed sores or “decubitis ulcers” affect bed ridden people by killing epidermal cells and then removes the barrier to infection by bacteria. -Nerve cells (merkel cells) are located here so bed sores affect these cells, sending intense pain stimuli to CNS.   Dermal Circulation and Nerve Supply (cont.): Subcutaneous layer – NOT part of integumentary system -Contains areola and adipose tissue -has substantial number of blood vessels therefore good place for injections with hypodermic needles. -This is the location of liposuction to remove adipocytes. Accessory Organs: Hair -Hair shaft is a protein (NO DNA) and are made by “hair follicles”. -Hair root – anchors hair to skin -Hair Shaft – part of hair we see on surface -Cuticle – outer surface of the shaft and covers the “cortex” -Hair papilla – a piece of connective tissue containing capillaries and nerves -Hair color comes from pigments “melanin”; with age pigment production decreases causing hair to become gray   Hair Types: Embryo Lanugos – Hairs formed after 3 months on embryo then are shed before birth Adult 1.  vellus hairs – “peach fuzz” covers body surface 2. terminal hairs – on head, eyebrows, eyelashes Hair Functions: -Root hair plexus – nerves surround the base so you can feel wind blow -Arrector pili – muscle that causes hair to stand up due to fear, rage, cold and emotional states   Accessory Organs: Glands in the Skin Two types of Exocrine Glands in skin (secretes into ducts) 1.  Sebaceous (also called Oil glands or holocrine glands) – produce oily lipid that coats hair. -Liquid released through rupture of the secretory cells and inhibits bacteria. A. Sebaceous glands- release onto hairs B. Sebaceous follicles- release onto the skin Accessory Organs: Glands in the Skin (cont.) 2.  Sweat Glands (cont.): – also called “sudoriferous glands” Two Subtypes: -Apocrine – arm pits and groin secrete their products onto hair follicles. -Bacteria use the sweat as a nutrient source which in turn produces an odor -Merocrine Glands – more numerous than aprocrine glands, secrete their products onto the surface of the skin. Found all over the body and in the palms of hands and soles of feet. Accessory Organs: Glands in the Skin (cont.) -Sweat produced by merocrine glands is called sensible perspiration which: a. cools the body, causes body temperature to decrease b. excretes salts, drugs c. protects against bacteria Other Glands: 1.  Mammary glands – produce milk 2.  Ceruminous glands – modified sweat glands in ears, secretions combines with secretions from sebaceous glands nearby to form wax (“cerumen”) Accessory Organs: Nails -nail body- covers area known as “nail bed” -nail folds – on each side of the nail -nail root – where growth starts -eponychium – portion of “stratum corneum” extends over nail at nail root (also called the cuticle) -Blood vessels – may be obscured near cuticle and make lunula “moon”         Repair of Skin due to injury: Incision – cut Abrasion – scrape Step one – Injury (cut or scrape) to skin causes bleeding to occur, blood clots to stop bleeding, mast cells detect injury and trigger an immune response. Step two – Scab formed over injury, cells from Stratum Germinativum move into area. Blood flow to region increases bringing more phagocytic cells. Step three – Scab undermined by epidermal cells to start repair; fibroblasts produce meshwork of “fibers” over top of injury creating scar tissue Step four – Scab disappears, fibroblasts continue to create scar tissue that will raise the overlapping epidermis higher than original skin. Repair of Skin due to injury (cont.): - Granulation tissue – combination of blood clot, fibroblasts, capillary network - Keloid – thickened area of scar tissue which has a shiny surface Aging: -Epidermis thins -number of langerhans cells decrease -D3 production drops -number of melanocytes decrease -gland activity reduces -blood supply to skin decreases -Collagen decreases making skin thinner and weaker -Elastin decreases making skin less tight more wrinkled -Moisture decreases making skin drier Medical conditions of the Integumentary System -Nails become yellow if have AIDS or thyroid gland problems -Psoriasis – rapid cell division of stem cells in Stratum Germinativum Diseases/conditions: -Albinism- results from genetic defect that prevents the amino acid tyrosine from being made; therefore the protein melanin cannot be produced causing the skin to have a white color. -psoriasis- stratum germinativum becomes highly active causing cells to divide every day (normally they divide one time every twenty days). Occurs on scalp, elbows, palms, soles of feet. Can be aggravated by stress or anxiety; no known cure but normally painless. -Microbial infections: -viral- fever blisters, genital herpes, chicken pox, shingles, warts -Bacterial- boils, impetigo, leprosy -Leprosy (Hansen’s disease) caused by a bacteria which destroys nerve endings thus the person cannot detect extreme heat/cold in hands. -fungal-ringworm, athletes foot, candidiasis -parasitic-scabies, swimmers itch Biol 2010 – A&P I Study Questions for Ch. 5 1. What constitutes the integumentary system? What are the major functions of the integumentary system? 2. Discuss the methods of heat transfer. Contrast sensible and insensible perspiration. Why do we sweat? What is sweat? Contrast merocrine and apocrine sweat glands and their products. What are sebaceous glands? What are cerumenous and mammary glands? 3. What types of pigments are found in the skin? What is the function of pigment? 4. What are the layers of the epidermis? Give the characteristics of each of the layers. How do thick and thin skin differ? What type of tissue and types of cells are found in the epidermis? 5. Describe the dermis and hypodermis. What types of tissue are here? Contrast the papillary and reticular layers. Give other terms for the hypodermis. 6. Describe hair and the associated structures. What is the function of hair? 7. Describe nails. Describe the growth of nails and compare it to the growth of hair. Define cutaneous membrane melanocytes Rickets osteoporosis keratin Epidermal ridges papillary layer reticular layer Elastic fibers collagen hair follicl Hair root hair shaft hair papilla Arrector pili muscle sebaceous gland nail root Nail bed nail body nail fold hyponychium eponychium Lunula Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Chapter 5 - Integumentary System Anatomy and Physiology I- Chapter 5 Integumentary System Anatomy and Physiology I- Chapter 5 – Chapter Objectives 2 Anatomy and Physiology I- Chapter 5 - Integumentary System Skin Functions: 1.    Protects tissue and organs from shock 2.     Excretes salts, water, wastes 3.     Maintenance of body temperature 4.     Makes vitamin D3 (a steroid) which is converted to calcitriol Storage of nutrients – lipids stored in adipocytes in dermis and subcutaneous layer   Chapter 5 - Integumentary System Two Major Parts of Integumentary System: 1.  Cutaneous Membrane -Epidermis – (“epi” means above) epithelia; does NOT have blood vessels; consists of stratified squamous -Dermis – under laying area of connective tissue; has a lot of blood vessels, epidermis doesn’t; consists of dense irregular -Another layer, deeper than dermis is called “subcutaneous layer” also called “hypodermis”. NOT part of cutaneous membrane   2. Accessories -Hair, nails, 4 types of exocrine glands    Keratinocytes – body’s most abundant epithelial cells; Types of Skin Layering  A. Thick skin – Five layers palms of hands and soles of feet: stratum germinativum (deepest) stratum spinosum stratum granulosum stratum lucidum (not found in thin skin) stratum corneum Thin skin – Four layers cover rest of body; 1. stratum germinativum (deepest) 2. stratum spinosum 3. stratum granulosum 4. stratum corneum     Epidermal Skin Layers: (Stratum means one layer; Strata means two + layers) 1). Stratum germinativum (stratum basal) – This is the deepest layer and is attached to the basal lamina. - About 1 cell layer thick. -Basal lamina separates epithelia from connective tissue. -Has epidermal ridges which extends into dermis which increases contact area between two places increasing attachment strength. -Germinativum Cells, also called basal cells, are found throughout stratum germinativum and are “stem cells” which replace the cells lost in the upper layers -Merkel Cells are sensitive to touch (pain receptors); when compressed by pressure they release chemicals that stimulate nerves. -Melanocytes produce brown pigment and are found here. Dermal Circulation and Color: -Hemoglobin (transports oxygen) looks red when attached to O2 -When hemoglobin is attached to CO2 vessels look blue   -When blood supply in dermis is reduced the skin becomes “pale”. -Jaundice – Liver unable to excrete bile so yellow pigment accumulates in body causing skin and eyes to turn yellow; occurs in newborns and can be easily cured by placing under a UV lamp.   Epidermal Skin Layers (cont.): 2). Stratum Spinosum – Each time one stem cell divides into two daughter cells, the daughter cell is pushed from stratum germinativum to stratum Spinosum. -Have 8 - 10 layers of cells -LangerHans cells (involved in immune response) are found in this layer and they: a. defend against microorganisms that penetrate skin b. attack superficial skin cancers   Epidermal Skin Layers (cont.): 3). Stratum Granulosum –(Also called “grainy layer”); this strata has 3-5 layers of keratinocytes. -When cells reach this layer they have quit dividing and start to make proteins keratin. These proteins are found in hair/nails.   4). Stratum Lucidum (Also called “Clear layer”) – Found only in thick skin of palms of hands and soles of feet. -Cells are flattened, densely packed and filled w/ keratin. Epidermal Skin Layers (cont.): 5). Stratum Corneum – Constitues the exposed areas of both thick and thin skin. Most superficial layer. -15 - 30 layers of keratinized cells. -Keratinization or “cornification” is the formation of a protective layer of cells w/ keratin. -It takes 15 - 30 days from cell to move from Stratum Germinativum to Stratum Corneum. -Dead cells remain on top of Stratum Corneum for two more weeks until pushed to skin surface and lost. Epidermal Skin Layers (cont.): -Stratum Corneum is H2O resistant but not H2O proof -500ml H2O lost by evaporation each day through skin. (insensible perspiration) -Sensible perspiration is produced by sweat glands. -Extreme Sunlight can damage skin, but is needed for Stratum Spinosum and Stratum Germinativum so they can convert a steroid into vitamin D3 (also called cholecalciferol). -Liver then converts D3 into an intermediary product used by the Kidney to to make calcitriol which is needed for calcium absorption and bone growth. This is why they put Vitamin D in milk because a lot of people do not get out in the sunlight enough to produce D3.     Pigments and Skin Color: -Carotene is orange/ yellow pigment in epidermis. -Comes from carrots and squash and is converted to vitamin A (important to eyes and epithelia)   -Melanin – is a brown, yellow brown or black pigment produced by melanocytes in epidermis. Albinos lack melanin. -Melanocytes are located in Stratum Germinativum and make melanin from AA tyrosine. -Protects against UV radiation (sun light) UV damages DNA causes skin cancers like malignant cancer` and melanoma. -Melanin concentration increases in response to sunlight Epidermal Growth Factor: – made in salivary glands; This hormone induces cells in epidermis to grow. Functions: Promotes division of cells in Stratum Germinativum and Stratum Spinosum 2. Accelerates Keratin production 3. Stimulates epidermal repair after injury Skin Cancers: Basal cell carcinoma – malignant cancer found in Stratum Germinativum (Most common form of cancer) due to UV radiation.   Dermis: (consists of two layers) 1). Papillary layer (superficial); consists of areolar tissue and contains capillaries and sensory neurons. 2). Reticular layer (deeper layer); consists of dense irregular tissue. -Accessory Organs (hair, sweat glands) extend into dermis. -Dermis also has blood vessels, lymph vessels, and nerve fibers. -Dermatitis is inflammation of the skin primarily in the papillary layer due to chemicals or radiation. Dermal Circulation and Nerve Supply: -If blood supply gets interrupted to the epidermis or dermis you can get an ulcer (shedding of epithelium) -Bed sores or “decubitis ulcers” affect bed ridden people by killing epidermal cells and then removes the barrier to infection by bacteria. -Nerve cells (merkel cells) are located here so bed sores affect these cells, sending intense pain stimuli to CNS.   Dermal Circulation and Nerve Supply (cont.): Subcutaneous layer – NOT part of integumentary system -Contains areola and adipose tissue -has substantial number of blood vessels therefore good place for injections with hypodermic needles. -This is the location of liposuction to remove adipocytes. Accessory Organs: Hair -Hair shaft is a protein (NO DNA) and are made by “hair follicles”. -Hair root – anchors hair to skin -Hair Shaft – part of hair we see on surface -Cuticle – outer surface of the shaft and covers the “cortex” -Hair papilla – a piece of connective tissue containing capillaries and nerves -Hair color comes from pigments “melanin”; with age pigment production decreases causing hair to become gray   Hair Types: Embryo Lanugos – Hairs formed after 3 months on embryo then are shed before birth Adult 1.  vellus hairs – “peach fuzz” covers body surface 2. terminal hairs – on head, eyebrows, eyelashes Hair Functions: -Root hair plexus – nerves surround the base so you can feel wind blow -Arrector pili – muscle that causes hair to stand up due to fear, rage, cold and emotional states   Accessory Organs: Glands in the Skin Two types of Exocrine Glands in skin (secretes into ducts) 1.  Sebaceous (also called Oil glands or holocrine glands) – produce oily lipid that coats hair. -Liquid released through rupture of the secretory cells and inhibits bacteria. A. Sebaceous glands- release onto hairs B. Sebaceous follicles- release onto the skin Accessory Organs: Glands in the Skin (cont.) 2.  Sweat Glands (cont.): – also called “sudoriferous glands” Two Subtypes: -Apocrine – arm pits and groin secrete their products onto hair follicles. -Bacteria use the sweat as a nutrient source which in turn produces an odor -Merocrine Glands – more numerous than aprocrine glands, secrete their products onto the surface of the skin. Found all over the body and in the palms of hands and soles of feet. Accessory Organs: Glands in the Skin (cont.) -Sweat produced by merocrine glands is called sensible perspiration which: a. cools the body, causes body temperature to decrease b. excretes salts, drugs c. protects against bacteria Other Glands: 1.  Mammary glands – produce milk 2.  Ceruminous glands – modified sweat glands in ears, secretions combines with secretions from sebaceous glands nearby to form wax (“cerumen”) Accessory Organs: Nails -nail body- covers area known as “nail bed” -nail folds – on each side of the nail -nail root – where growth starts -eponychium – portion of “stratum corneum” extends over nail at nail root (also called the cuticle) -Blood vessels – may be obscured near cuticle and make lunula “moon”         Repair of Skin due to injury: Incision – cut Abrasion – scrape Step one – Injury (cut or scrape) to skin causes bleeding to occur, blood clots to stop bleeding, mast cells detect injury and trigger an immune response. Step two – Scab formed over injury, cells from Stratum Germinativum move into area. Blood flow to region increases bringing more phagocytic cells. Step three – Scab undermined by epidermal cells to start repair; fibroblasts produce meshwork of “fibers” over top of injury creating scar tissue Step four – Scab disappears, fibroblasts continue to create scar tissue that will raise the overlapping epidermis higher than original skin. Repair of Skin due to injury (cont.): - Granulation tissue – combination of blood clot, fibroblasts, capillary network - Keloid – thickened area of scar tissue which has a shiny surface Aging: -Epidermis thins -number of langerhans cells decrease -D3 production drops -number of melanocytes decrease -gland activity reduces -blood supply to skin decreases -Collagen decreases making skin thinner and weaker -Elastin decreases making skin less tight more wrinkled -Moisture decreases making skin drier Medical conditions of the Integumentary System -Nails become yellow if have AIDS or thyroid gland problems -Psoriasis – rapid cell division of stem cells in Stratum Germinativum Diseases/conditions: -Albinism- results from genetic defect that prevents the amino acid tyrosine from being made; therefore the protein melanin cannot be produced causing the skin to have a white color. -psoriasis- stratum germinativum becomes highly active causing cells to divide every day (normally they divide one time every twenty days). Occurs on scalp, elbows, palms, soles of feet. Can be aggravated by stress or anxiety; no known cure but normally painless. -Microbial infections: -viral- fever blisters, genital herpes, chicken pox, shingles, warts -Bacterial- boils, impetigo, leprosy -Leprosy (Hansen’s disease) caused by a bacteria which destroys nerve endings thus the person cannot detect extreme heat/cold in hands. -fungal-ringworm, athletes foot, candidiasis -parasitic-scabies, swimmers itch Biol 2010 – A&P I Study Questions for Ch. 5 1. What constitutes the integumentary system? What are the major functions of the integumentary system? 2. Discuss the methods of heat transfer. Contrast sensible and insensible perspiration. Why do we sweat? What is sweat? Contrast merocrine and apocrine sweat glands and their products. What are sebaceous glands? What are cerumenous and mammary glands? 3. What types of pigments are found in the skin? What is the function of pigment? 4. What are the layers of the epidermis? Give the characteristics of each of the layers. How do thick and thin skin differ? What type of tissue and types of cells are found in the epidermis? 5. Describe the dermis and hypodermis. What types of tissue are here? Contrast the papillary and reticular layers. Give other terms for the hypodermis. 6. Describe hair and the associated structures. What is the function of hair? 7. Describe nails. Describe the growth of nails and compare it to the growth of hair. Define cutaneous membrane melanocytes Rickets osteoporosis keratin Epidermal ridges papillary layer reticular layer Elastic fibers collagen hair follicl Hair root hair shaft hair papilla Arrector pili muscle sebaceous gland nail root Nail bed nail body nail fold hyponychium eponychium Lunula Chapter 5 - Integumentary System Anatomy and Physiology I- Chapter 5 Integumentary System Anatomy and Physiology I- Chapter 5 – Chapter Objectives 2 Anatomy and Physiology I- Chapter 5 - Integumentary System Skin Functions: 1.    Protects tissue and organs from shock 2.     Excretes salts, water, wastes 3.     Maintenance of body temperature 4.     Makes vitamin D3 (a steroid) which is converted to calcitriol Storage of nutrients – lipids stored in adipocytes in dermis and subcutaneous layer   Chapter 5 - Integumentary System Two Major Parts of Integumentary System: 1.  Cutaneous Membrane -Epidermis – (“epi” means above) epithelia; does NOT have blood vessels; consists of stratified squamous -Dermis – under laying area of connective tissue; has a lot of blood vessels, epidermis doesn’t; consists of dense irregular -Another layer, deeper than dermis is called “subcutaneous layer” also called “hypodermis”. NOT part of cutaneous membrane   2. Accessories -Hair, nails, 4 types of exocrine glands    Keratinocytes – body’s most abundant epithelial cells; Types of Skin Layering  A. Thick skin – Five layers palms of hands and soles of feet: stratum germinativum (deepest) stratum spinosum stratum granulosum stratum lucidum (not found in thin skin) stratum corneum Thin skin – Four layers cover rest of body; 1. stratum germinativum (deepest) 2. stratum spinosum 3. stratum granulosum 4. stratum corneum     Epidermal Skin Layers: (Stratum means one layer; Strata means two + layers) 1). Stratum germinativum (stratum basal) – This is the deepest layer and is attached to the basal lamina. - About 1 cell layer thick. -Basal lamina separates epithelia from connective tissue. -Has epidermal ridges which extends into dermis which increases contact area between two places increasing attachment strength. -Germinativum Cells, also called basal cells, are found throughout stratum germinativum and are “stem cells” which replace the cells lost in the upper layers -Merkel Cells are sensitive to touch (pain receptors); when compressed by pressure they release chemicals that stimulate nerves. -Melanocytes produce brown pigment and are found here. Dermal Circulation and Color: -Hemoglobin (transports oxygen) looks red when attached to O2 -When hemoglobin is attached to CO2 vessels look blue   -When blood supply in dermis is reduced the skin becomes “pale”. -Jaundice – Liver unable to excrete bile so yellow pigment accumulates in body causing skin and eyes to turn yellow; occurs in newborns and can be easily cured by placing under a UV lamp.   Epidermal Skin Layers (cont.): 2). Stratum Spinosum – Each time one stem cell divides into two daughter cells, the daughter cell is pushed from stratum germinativum to stratum Spinosum. -Have 8 - 10 layers of cells -LangerHans cells (involved in immune response) are found in this layer and they: a. defend against microorganisms that penetrate skin b. attack superficial skin cancers   Epidermal Skin Layers (cont.): 3). Stratum Granulosum –(Also called “grainy layer”); this strata has 3-5 layers of keratinocytes. -When cells reach this layer they have quit dividing and start to make proteins keratin. These proteins are found in hair/nails.   4). Stratum Lucidum (Also called “Clear layer”) – Found only in thick skin of palms of hands and soles of feet. -Cells are flattened, densely packed and filled w/ keratin. Epidermal Skin Layers (cont.): 5). Stratum Corneum – Constitues the exposed areas of both thick and thin skin. Most superficial layer. -15 - 30 layers of keratinized cells. -Keratinization or “cornification” is the formation of a protective layer of cells w/ keratin. -It takes 15 - 30 days from cell to move from Stratum Germinativum to Stratum Corneum. -Dead cells remain on top of Stratum Corneum for two more weeks until pushed to skin surface and lost. Epidermal Skin Layers (cont.): -Stratum Corneum is H2O resistant but not H2O proof -500ml H2O lost by evaporation each day through skin. (insensible perspiration) -Sensible perspiration is produced by sweat glands. -Extreme Sunlight can damage skin, but is needed for Stratum Spinosum and Stratum Germinativum so they can convert a steroid into vitamin D3 (also called cholecalciferol). -Liver then converts D3 into an intermediary product used by the Kidney to to make calcitriol which is needed for calcium absorption and bone growth. This is why they put Vitamin D in milk because a lot of people do not get out in the sunlight enough to produce D3.     Pigments and Skin Color: -Carotene is orange/ yellow pigment in epidermis. -Comes from carrots and squash and is converted to vitamin A (important to eyes and epithelia)   -Melanin – is a brown, yellow brown or black pigment produced by melanocytes in epidermis. Albinos lack melanin. -Melanocytes are located in Stratum Germinativum and make melanin from AA tyrosine. -Protects against UV radiation (sun light) UV damages DNA causes skin cancers like malignant cancer` and melanoma. -Melanin concentration increases in response to sunlight Epidermal Growth Factor: – made in salivary glands; This hormone induces cells in epidermis to grow. Functions: Promotes division of cells in Stratum Germinativum and Stratum Spinosum 2. Accelerates Keratin production 3. Stimulates epidermal repair after injury Skin Cancers: Basal cell carcinoma – malignant cancer found in Stratum Germinativum (Most common form of cancer) due to UV radiation.   Dermis: (consists of two layers) 1). Papillary layer (superficial); consists of areolar tissue and contains capillaries and sensory neurons. 2). Reticular layer (deeper layer); consists of dense irregular tissue. -Accessory Organs (hair, sweat glands) extend into dermis. -Dermis also has blood vessels, lymph vessels, and nerve fibers. -Dermatitis is inflammation of the skin primarily in the papillary layer due to chemicals or radiation. Dermal Circulation and Nerve Supply: -If blood supply gets interrupted to the epidermis or dermis you can get an ulcer (shedding of epithelium) -Bed sores or “decubitis ulcers” affect bed ridden people by killing epidermal cells and then removes the barrier to infection by bacteria. -Nerve cells (merkel cells) are located here so bed sores affect these cells, sending intense pain stimuli to CNS.   Dermal Circulation and Nerve Supply (cont.): Subcutaneous layer – NOT part of integumentary system -Contains areola and adipose tissue -has substantial number of blood vessels therefore good place for injections with hypodermic needles. -This is the location of liposuction to remove adipocytes. Accessory Organs: Hair -Hair shaft is a protein (NO DNA) and are made by “hair follicles”. -Hair root – anchors hair to skin -Hair Shaft – part of hair we see on surface -Cuticle – outer surface of the shaft and covers the “cortex” -Hair papilla – a piece of connective tissue containing capillaries and nerves -Hair color comes from pigments “melanin”; with age pigment production decreases causing hair to become gray   Hair Types: Embryo Lanugos – Hairs formed after 3 months on embryo then are shed before birth Adult 1.  vellus hairs – “peach fuzz” covers body surface 2. terminal hairs – on head, eyebrows, eyelashes Hair Functions: -Root hair plexus – nerves surround the base so you can feel wind blow -Arrector pili – muscle that causes ha