HLSC 120 W2025 Ch 5 Integumetary Jan 7 2025 Class Notes PDF

CHAPTER 5 Integumentary System  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Information Integumentary System Composed of: Skin Hair Oil...

CHAPTER 5 Integumentary System  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Information Integumentary System Composed of: Skin Hair Oil and sweat glands Nails Sensory receptors Functions: Protection Maintenance of constant body temperature Dermatology: Medical specialty dealing with structure, function, and disorders of integumentary system Integumentary System: Skin Skin: largest organ in body (two square meters) 7 % of body weight Three main layers form integument 1. Epidermis Avascular (so no bleeding when you just scratch yourself) Various epithelial cells 2. Dermis Connective tissue deep to epidermis Vascular (you bleed If cut deep enough to damage dermis) 3. Subcutaneous Deep to dermis (but not part of skin) Contains adipose tissue  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Information Epidermis: composed of keratinized, stratified, squamous, epithelium Contains four types of cells: Keratinocytes Melanocytes Dendritic Tactile Epithelial cells Tough Produce pigment Or Langerhans Merkel cells Four/five melanin which cells Detect touch layers controls skin color Arise from red sensations (hence (stratified) Long armlike bone marrow sensory neuron) Produce processes contact Part of immune 2% of cells protein keratin various response 85% of E cells keratinocytes 5% of cells 8% of cells Top layer is epidermis. It is composed of five layers Epidermis: thin and thick Skin Thin Skin has four layers (all called Stratum) from deep to superficial. 1. Basale 2. Spinosum 3. Granulosum 4. Corneum 1 1. Basale Deepest layer Single row of columnar keratinocytes (stem cells) Role: form new cells (keratinocytes) Protects dermis and deeper layers from damage Epidermis: thin and thick Skin 2. Spinosum Numerous layers (8-10) of keratinocytes produced by Basale Keratinocytes start to become flatter and flatter Desmosomes join cells together in 2 tighter and tighter arrangement 1 Provides strength and flexibility Epidermis: thin and thick Skin 3. Granulosum Consists of 3-5 layers of flattened dying 4 keratinocytes (apoptosis) Located too far from arterial system in 3 Dermis 2 4. Corneum 1 25-30 layers of flattened dead keratinocytes No longer have nuclei or organelles Overlap like snake scales Cells are shed and replaced on continual basis Epidermis: thin and thick Skin Thick Skin has an additional layer 5. Lucidum 5 Lies between corneum and granulosum. Present in fingertips, palms, and soles of feet 4-6 layers of flat, clear, dead keratinocytes Provides additional layer of toughness From Basale to Corneum (sloughed off) takes 4-6 weeks Dandruff: excessive number of cells shed from scalp 4 5 3 2 Dendritic cell 1  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Information Dermis Dermis = dense connective tissue Contains collagen and elastic fibers (no reticular fibers) 1 Divided into Papillary (1) and Reticular (2) 2 regions Dermis Thicker than epidermis Thickest: palms and soles of feet 1 Resistant to pulling or stretching Essential to epidermis survival 2 Divided into two sections. Papillary Reticular Superficial portion (1/5 of Deep portion (4/5) dermis) Dense irregular connective tissue Thin collagen and elastic fibers Primarily thick collagen fibers and elastic fibers / Contains: blood capillaries, fibroblasts corpuscles of touch, and free Contains blood vessels, hair follicles, nerves, nerve endings. sebaceous glands (lubricate hair shaft) and sudoriferous glands (sweat glands) Sebaceous: suh-bay-shush / Sudoriferous: soo –doh-rif-er-us  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Informtion Subcutaneous Subcutaneous Layer Deep to dermis / referred to as “Hypodermis” Storage for adipose tissue Contains large blood vessels that drain skin capillaries Fibers attach Dermis to underlying fascia Functions: Shock absorption and protection Insulation = helps manage heat loss Energy storage Structural Basis for Skin color Skin color result of three pigments in skin 1. Melanin Two forms of melanin: 1. pheomelanin (yellow to red) 2. eumelanin (u-melanin) (brown to black) The difference between the two forms is most apparent in hair 2. Hemoglobin from Red Blood Cells Creates a reddish hue to the skin 3. Carotene (care-ah-teen): Yellow-orange pigment from carotene rich foods Stored in the stratum corneum and fatty areas in response to excessive dietary intake Structural Basis for Skin color Melanin Number of melanocytes is same in all people = difference in skin color is due to amount of pigment cells produce and transfer to karatinocytes Exposure to ultraviolet light causes DNA damage which causes an increase in melanin production to protect against further damage Freckles: accumulation of melanin into patches Melanin is synthesized from amino acid tyrosine Tan is lost when melanin-containing keratinocytes are shed from stratum corneum  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Information Accessory Structures of the Skin Two (2) accessory structures 1. Hair 2. Nails Both develop from epidermis Basic Functions: Hair and Nails = protection of body Sweat glands = regulate body temperature Accessory Structures of the Skin: Hair Hair absent from palms, palmer surfaces of fingers, soles, and plantar surfaces of toes Hair on head guards scalp from injury and sun’s rays Touch receptors associated with hair roots are activated by slightest movement of hair 1 Eyebrows and eyelashes protect eyes from foreign objects 2 Hair composed of columns of dead keratinized epidermal cells Hair shaft (1): Superficial portion of hair which projects upwards from skin Hair root (2): Deep to hair shaft (penetrates Dermis) Accessory Structures of the Skin: Hair Goose Bumps Arrector pili (1): extends from superficial aspect of dermis (red dot) to hair bulb (blue dot) Under emotional distress, cold, anger, etc. arrector contracts and pulls hair shaft perpendicular to skin Goose bumps = slight elevation of skin around hair shaft Animals: process important for survival Used to trap dead air / use it as insulation Make animal look bigger and more formidable. 1 Accessory Structures of the Skin: Nails 1) Nail plate (body): visible portion of nail /tightly packed dead keratinocytes Comparable to stratum corneum but it does not shed Below nail plate is a layer of epithelium and dermis Nail body pink due to blood flow underneath 2) Free edge: nail extending past the distal end of the digit 3) Nail root: part of skin buried in a fold of skin 3 1 2 Accessory Structures of the Skin: Nails 4) Lunula (means “little moon”): crescent shaped area at proximal end of nail plate 5) Hyponychium: beneath the free edge, a region of thickened stratum corneum that secures the nail to the fingertip 6) Eponychium (cuticle): is the stratum corneum of the epidermis 7) Nail matrix: contains dividing cells which produce new nail cells 6 4 5 7  Integumentary System 1. Introduction 2. Structure of the Skin a) Epidermis b) Dermis c) Subcutaneous 3. Accessory Structure of the Skin 4. Additional Information Additional Information: Burns First-Degree Second-Degree Third-Degree Involves only Portion of epidermis Full-thickness burn epidermis and dermis Most skin functions Skin functions Some skin functions lost remain intact lost Nerve ending Heal in 3-6 days Redness, blisters, pain destroyed Flaking and If no infection: 3-4 Regeneration occurs peeling weeks to heal slowly Example: mild Called: partial- Skin grafting may be sunburn thickness burn required Additional Information: Tattoos/Piercings Tattoos Practice originated in ancient Egypt 4000 – 2000 B.C. Tattoos = injecting ink (via needle) that punctures epidermis and deposits ink in dermis Dermis is stable = tattoos are permanent https://www.ranker.com/list/navy-tattoos- and-their-meanings/mike-rothschild Body Piercing Ancient practice by Egyptian Pharaohs and Roman soldiers Total healing can take up to a year https://www.casadel.ca/body-piercing/  Integumentary Phonological Visuospatial chunks chunks Skin Epidermis, dermis, subcutaneous Epidermis 4 cells: keratinocytes (90%), melanocytes (melanin), macrophage (immune), tactile (touch) Dermis -dense connective tissue / Papillary 1/5, thin collagen and fibers / Reticular 4/5 thick stuff, blood, glands, nerves, follicles Subcutaneous Not part of skin / adipose tissue / (hypothermic) large blood vessels / attachment Hair Dead keratinocytes / shaft and root Nails Dead Keratinocytes, like Stratum Corneum but doesn’t shed Burns First: epidermis / Second: epi + dermis / Third: full-thickness, nerve ends destruction  Tissue/Integumentary Questions 1. Which classification of surface ET (number of cells) has two or more layers? __________ 2. What Surface ET is thin and allows rapid passage of substances? ______________ 3. Exocrine glands secrete ____________ / Endocrine secrete _____________ 4. The “Jello” of Marshmallow Jello represents ________________________ 5. Immature phase connective tissue cells are called ___________ 6. ________ trap water and make ground substance more jelly like. 7. What type of Mature CT are tendons? 8. With Synovial membranes, syn = ? 9. __________ muscle have Gap Junctions. 10. _______________ is the medical specialty dealing with the integumentary system 11. Which layer is vascular?: epidermis, dermis subcutaneous 12. Which cell of the epidermis arises from red bone marrow? 13. Which skin layer forms new keratinocytes? 14. Which layer is only in Thick Skin? 15. What portion of Dermis is the Papillary? 16. Which form of Melanin is ”yellow to red”? 17. What hair muscle contracts and pulls hair shaft perpendicular?