Chapter 5: The Integumentary System PDF

Chapter 5: The Integumentary System 5.1 The skin consists of two layers: the epidermis and dermis. List the two layers of skin and briefly describe subcutaneous tissue. Epidermis - Composition: epithelial cells - non-vascularized Dermis...

Chapter 5: The Integumentary System 5.1 The skin consists of two layers: the epidermis and dermis. List the two layers of skin and briefly describe subcutaneous tissue. Epidermis - Composition: epithelial cells - non-vascularized Dermis epidermis - Composition: dense connective tissue. - vascularized Subcutaneous tissue dermis - Hypodermis - Superficial fascia hypodermis 5.2 The epidermis is a keratinized stratified squamous epithelium. Name the tissue type composing the epidermis. List the major layers of the epidermis and describe the functions of each layer. Major tissue type: Keratinized stratified squamous epithelium Layers of the Epidermis Layer Function Stratum Basale & buttered ______________________________ renewing (mitosis) cell population - skin cells, melanocytes Stratum Spinosum Resist cell tension salted anchored to the desmosomes Pre keratin several layers of keratinocytes Stratum Granulosum Keratinization good keratin + glycolipids - extracellular space Stratum Lucidum Dead keratinocytes looks ____________________ absent in thin skin Thick skin location palms, soles, fingertips corn Stratum Corneum Keratin Glycolipids __________________regularly sheds kerantinocytes Cells of the Epidermis Kera%nocytes Func4on: produce kera4n Origin: stratum __________________. basale Features: desmosomes and 4ght junc4ons Replica4on: con4nuous mitosis s. corneum Melanocytes Loca4on: stratum ___________________. basale Synthesize: melanin Uptake: Dendri%c cells (Langerhans cells) s. granulosm Origin: bone marrow Func4on: phagocytes s. spinosum Tac%le epithelial cells (or Merkel cells) Loca4on: epidermal-dermal junc4on. s. basale Func4on: sensory receptors desmosomes tactile epithelial melanocytes cell 5.3 The dermis consists of papillary dermis and reticular dermis. Name the tissue types composing the dermis. List its major layers and describe the functions of each layer. Layers of the dermis include the papillary and reticular layer. Papillary layer of Dermis Composition - areolar _________________________ connective tissue Features papillary dermal papillae - Collagen and elastic fibers. layers - Dermal papillae contain o Free nerve endings o Tactile corpuscles dermis reticular o capillary loops layer “Fingerprints” Friction ridge patterns - dermal papillae - dermal ridges friction ridges - epidermal ridges Reticular layer of Dermis Significance: __________ 80% of thickness of the dermis Composition - dense irregular ___________________________ connective tissue o Collagen fibers o Elastic fibers Cleavage (_____________________) tension lines epidermis - Formation: separations between the bundles of collagen fibers. - Significance: incisions made parallel to the cleavage lines. Flexure lines - Dermal folds near joints, wrists, fingers, soles, and toes - Dermis is tightly secured to deeper structures papillary dermis - Dermis folds and deep skin creases form. areolar ct Stretch marks (______________________) striae - tears in the dermis reticular dermis o pregnancy dense irregular ct o fast muscle growth cleavage lines flexure lines sweat friction ridges duct epidermal dermal papillae ridges dermal ridges 5.4 Melanin, carotene, and hemoglobin determine skin color. Describe the factors that normally contribute to skin color. melanin (organic) Melanin - uv light protective properties Synthesis: tyrosine Two forms: reddish yellow to brownish black. melanocytes Enzyme: tyrosinase in ____________________________. # of melanocytes doesn't change but varies is amount of melanin Carotene - yellow to orange pigment - found in carrots Accumula'on - corneum Stratum ________________________ - fat of the subcutaneous 4ssue Vitamin A synthesis - epidermal health and normal _______________________. vision Hemoglobin - The pinkish hue of fair skin - Circulates through the dermal capillaries. Homeostatic imbalance sunscreen Excessive sun exposure - Elastic fibers clump - leathery skin Briefly describe how changes in skin color may be used as clinical signs of certain disease states. Blueness (Cyanosis) pallor - Poor __________________ oxygenation results in bluish-gray 4nt cyanosis - nail beds - cardiovascular or respiratory system issues Pallor - Emo4onal stress, low blood pressure, anemia - blood _______________ diverted from skin to internal organs - person to look white Redness - embarrassment, fever, inflamma4on, or allergy bruises Yellowness - liver not func4oning properly - Eliminates ______________________. bilirubin - accumulates in body 4ssue Result: - jaundice ______________________, a yellow discolora4on - Sclerae of the eyes Red/purple/green/yellow marks - Bruises/ecchymosis/hematoma jaundice - blood vessels - capillaries damaged _______________________________ - leaks blood into surrounding 4ssue. Brown or black necklace - Dark area in the axillae and around the neck - areas of velvety hyperpigmenta4on - sign of _____________________________________ insulin resistance & increase blood glucose 5.5 Hair consists of dead, kera4nized cells. hair shaft Name the regions of a hair and explain the basis of hair color Describe the func4onal rela4onship of arrector pili muscles to the hair follicles. Structure of a hair/hair root - Dead, kera4nized cells - Three concentric layers include the Medulla, cortex, and cu%cle Medulla hair root - central core - contains soR kera4n - absent in fine hairs Cortex - Surrounds the medulla that contains flaTened cells - Melanocytes - coritcal Melanin uptake via __________________ cells keratinocytes hair root o Grey hair cuticle o Red hair cortex § Pheomelanin medulla hair matrix Cu%cle - Outermost layer hair papillae - Most heavily kera4nized Arrector pili muscle - Contrac4on result - Goose bumps Structure of a hair follicle List the parts of a hair follicle and explain the func4on of each part. Describe the distribu4on, growth, replacement, and changing nature of hair during the life span. fibrous sheath Hair follicle forma4on - fold down from epidermal surface into subcutaneous 4ssue glassy membrane Hair bulb epithelial root sheath - boTom of hair follicle ext root sheath int root sheath Hair papilla - Dermal papillae o protrudes into hair bulb o contains _______________________. capillaries - supply nutrients Wall of the hair follicle components Peripheral connec%ve %ssue sheath (fibrous sheath) - derived from the _________________________ dermis - Forms the external layer of the follicle wall Glassy membrane Loca4on - junc4on of the fibrous sheath and the epithelial root sheath - basement membrane of the follicle epithelium hair bulb Epithelial root sheath thickest layer with two components. Derived from the _____________________________ 1. External root sheath - a direct con4nua4on of the ____________ 2. Internal root sheath - derived from the matrix cells  exocrine glands holocrine v merocrine 5.6 Nails are scale-like modifications of the epidermis. lunle lateral nail bruptare exocytosis Describe the structure of nails. tubular v areolar General simple v compound - hard Nails contain _________________ keratin - Epidermis contains _________________ soft keratin - Pink color sweat (sudoriferous) glands Structures eccrine-merocrine-tubular Nail matrix - apocrine-merocrine-tubular Nail root - Embedded in the skin oil (sebaceous) glands Lunule free nail eponychium - white crescent edge plate nail root Nail folds proximal nail matrix - Proximal and lateral borders nail fold Cuticle - proximal nail fold Nail plate or body - mai portion Nail bed - Epidermal layer deep to the nail plate Hyponychium - dirt accumulates Free edge hyponychium nail bed - distal end that gets clipped 5.7 Sweat glands help control body temperature, and sebaceous glands secrete sebum Compare the structure and locations of sweat and oil glands. Also compare the composition and functions of their secretions. Compare and contrast eccrine and apocrine glands. Sweat (__________________________________) suberiferous glands Distribu4on - En4re skin surface Excep4ons - Nipples and external genitalia parts Types of sweat glands include Eccrine and Apocrine Myoepithelial cells - Secretory cells clear and dark cells - Contrac4on via Autonomic Nervous System involuntary Eccrine (______________________________) merocrine sweat glands Structure - Simple, coiled, tubular gland Amount - Merocrine > Apocrine Location - palms, soles of the feet, and forehead. Features - secretory part in the dermis - duct extends and opens on skin surface Sweat features Function - prevent overheating of body Formation - Pass through secretory cells (_______________________________________) clear and dark cells - released via exocytosis Components of sweat - Hypotonic filtrate of the blood o 99% water with salts o Trace metabolic wastes (urea and ammonia) o Dermacidin antimicrobial peptide § pH = 4 - 6 Apocrine sweat glands Structure - Simple, coiled, tubular gland. Loca4on - ________________________ and anogenital areas Features - Ducts empty into hair follicles. ___________________________ glands - secre4on contains true sweat, faTy substances, and proteins. Development - puberty Func4on - _______________________ secre4on Evidence: human equivalence of other animals’ sexual scent glands (1) Sexual foreplay increases their ac4vity. (2) enlarge and recede à phases of a woman’s menstrual cycle. (3) behavioral studies à secre4ons may act as pheromones. Modified Apocrine glands Ceruminous glands Loca4on - lining of the external ear canal Secre4on - mixes with sebum produced by nearby sebaceous glands - forms cerumen, or earwax Func4on - deter insects and block entry of foreign material. Mammary glands Loca4on: Breast 4ssue Func4on: Secrete breast milk Sebaceous glands (Oil glands) Structure - simple, alveolar glands Location - all over the body - NOT found in thick skin of the palms and soles holocrine _____________________________ glands - Central cells of the alveoli - accumulate oily lipids until engorged à burst. Arrector pili - contractions force sebum out of the hair follicles to the skin surface. Sebum Secretion - into a hair follicle - pore on the skin surface - increased activity during ______________________ Components - Oily substance o lipids and cell fragments. Sebum function - softens and lubricates the hair and skin - prevents hair from becoming brittle - slows water loss from the skin - bactericidal 5.8 -> skin is a barrier Protection Chemical barriers Skin secretions and melanin - Melanin - Low pH of skin secretions o Acid mantle o Defensins Physical barriers - Hardness of its keratinized cells Biological barriers Dendritic cells (Langerhans cell) - phagocytes Dermal macrophages - phagocytes Cutaneous Sensation Tactile (Meissner’s) corpuscles - dermal papillae - fine touch Free nerve endings - throughout dermis - nocireceptors ______________________ and thermoreceptors Lamellar (Pacinian) corpuscles - deep dermis - deep ____________________ pressure or vibration Body Temperature Regulation - Skin surface loses heat when outside temperature is lower than body temp. Metabolic Functions - Sunlight stimulates modified cholesterol molecules conversion to a vitamin ________ D precursor. Excretion - Eliminates small amounts of nitrogenous wastes in sweat o ammonia, urea, and uric acid - Most nitrogenous wastes excreted in urine. - Profuse sweating = water and salt loss Blood Reservoir Blood shunted to muscles during exercise via dermal blood vessel constriction, controlled by Nervous System. 5.9 Skin cancer and burns are major challenges to the body. Summarize the characteristics of the three major types of skin cancers. Skin Cancer Basal Cell Carcinoma - basale Stratum ________________________ cells proliferate - invade dermis and subcutaneous tissue Location - Often on sun-exposed areas of the face Appearance changes - Initially as shiny, dome-shaped nodules basal cell carcinoma - Later develop a central ulcer with a pearly, beaded edge Squamous Cell Carcinoma - keratinocytes _________________________ of the stratum spinosum Location - head (scalp, ears, and lower lip) - hands squamous cell carcinoma Appearance - scaly reddened papule - small, rounded elevation Melanoma - Typically appear spontaneously - one-third develop from ___________________________. preexsisting moles melanoma Appearance - spreading brown to black patch - metastasize rapidly to surrounding lymph and blood vessels ______________ most dangerous Explain why serious burns are life threatening. Describe how to determine the extent of a burn and whether it is a first-, second-, or third - degree burn. Burns - tissue damage inflicted by intense o heat, electricity, radiation, or certain chemicals - kills cells in the affected areas. - leads to dehydration and electrolyte imbalance 1st degree - renal failure and circulatory shock First-degree burns Damage 2nd degree - epidermis _____________________ only Symptoms - localized redness, swelling, and pain. Recovery - days Heals in two to three _________________ 3rd degree Second-degree burns Damage - upper dermis epidermis and _______________________ Symptoms blisters - Like first-degree burns with ___________________ Recovery - burned area is red and painful - weeks little or no scarring within three to four __________________ - wound care essential to prevent infection. rule of 9 Third-degree burns - full-thickness burns, involves entire thickness of the skin 11 areas - burned area appears gray-white, cherry red, or blackened burns critical if: - initially there is little or no edema. > 2.5 % -> 2nd degree - Skin grafts used >10% -> 3rd degree