Integumentary System Anatomy and Physiology PDF

ANATOMY Ateneo de Naga University College of Nursing  Learning Objectives: Integumentary System 01 02 03 Describe the Differentiation of Know the structure (anatomy) Thick and Thin Integumentary and func...

ANATOMY Ateneo de Naga University College of Nursing  Learning Objectives: Integumentary System 01 02 03 Describe the Differentiation of Know the structure (anatomy) Thick and Thin Integumentary and functions Skin (layers & System’s clinical (physiology) of the location) correlation Epidermis & Dermis  Fun Facts of Integumentary System Palms, Soles & Lips Palms & Soles only Back of hand & Abdomen 15% & 0% Eyelids & Postauricular region ‘Scar’ tissue VS ‘Normal’ tissue  SKIN Made up of 2 major layers: EPIDERMIS DERMIS Subcutaneous Tissue  Major Functions (Integumentary System) Protection Skin’s structures reduces the negative and harmful effects of UV light Keeps microorganisms from entering the body Prevention of dehydration Sensation Has sensory receptors that detects heat, cold, touch, pressure and pain Temperature Regulation Modulation of blood flow helps regulate the body temperature Vitamin D production Skin produces molecule (7-dehydrocholesterol) that can be transformed to active vitamin D Excretion Waste product excreted via skin and glands  EPIDERMIS Major Function Cell Composition Abrasion resistance Keratinocytes – major cell type Reduction of water loss Melanocytes – produces melanin Thinner than the dermis Langerhans cells – epidermis’ guardian Separated from the dermis by basement membrane Merkel cells – light touch and superficial pressure detection Receive nutrients and excrete waste via diffusion  Epidermis - KERATINOCYTES Constantly loss at the surface and constantly replaced at the base (highly mitotic) Most active in mitosis are the keratinocytes nearest to the BM After about 3 layers away from BM, mitosis stops Keratinization – process by which keratinocytes losses its organelles and are replaced with protein keratin. Keratinized keratinocytes are considered dead cells but provides the most protection against physical injuries and dehydration  Epidermis - MELANOCYTES Irregularly shaped cells with many long processes Produces and packages melanin into vesicles called Melanosomes All keratinocytes can contains melanin but ONLY melanocytes produces melanin  Epidermis – LANGERHANS CELLS Part of immune system, augments innate immune responses (macrophage that migrates to the skin) Migrate from the skin to lymph nodes where they present their antigenic cargoes to T lymphocytes  Epidermis – MERKEL CELLS Type of nerve endings Specialized epidermal cells Responsible for detecting light touch and superficial pressure Epidermis – EPIDERMAL LAYERS (STRATA) Strata = layer / series of layers 5 strata Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Number of cells and strata vary depending on the location in the body  EPIDERMAL LAYERS – stratum basale Aka ‘stratum germinativum’ → where germination happens Deepest portion Single layer of cubiodal to columnar cells Anchored to BM by HEMIDESMOSOMES Attached to lateral basal keratinocyte by DESMOSOMES Mitosis every approx. 19 days Approx 40-55 days before each cell reach the surface and slough off EPIDERMAL LAYERS – stratum spinosum Consist of 8-10 layers Cells flatten while they are pushed toward the surface Appears as such due to disintegration of old desmosomes and formation of new ones Appears spiny (hence the name) → due to shrinking of cells except in the part where desmosomes are attached Additional features of keratinocytes in this strata: keratin fibers and lamellar bodies  EPIDERMAL LAYERS – stratum granulosum Middle layer, 2-5 layers Somewhat flattened, diamond-shaped cells KERATOHYALIN = protein granules (hence the name) which accumulate in the cytoplasm of keratinocyte in this strata Degeneration of nucleus and other organelles starts → cell dies Keratin fibers & keratohyalin granules DOES NOT degenerate EPIDERMAL LAYERS – stratum lucidum Thin clear zone Several dead cell layers, indistinct boundaries Cells appear somewhat transparent (hence the name) Present only in few areas of the body (PALMS and SOLES) (+) S. lucidum = thick skin / (–) S. lucidum = thin skin EPIDERMAL LAYERS – stratum corneum Most superficial >25 overlapping layers Consist of CORNIFIED CELLS = dead cell with hard protein envelope filled with keratin Protein envelope + keratin = structural strength of S. corneum KERATIN = keratin fibers + keratohyalin HARD KERATIN = keratin in nails and external hair; more durable, does not shed SOFT KERATIN = keratin in skin 5 strata summary 5 strata summary  THICK SKIN THIN SKIN 5 epithelial strata 4 epithelial strata (no S. lucidum) Found in areas subject to pressure and Covers the rest of the body friction More flexible Palms and Soles, fingertips (+) hair (–) hair Each strata has fewer layers that thick skin Callus: forms with excessive friction/pressure at the s. corneum = increases thickness Corn: cone-shaped structure developed in the skin over bony prominences; can be painful with pressure  Thick skin VS Total Skin thickness Thick skin (and thin skin) are used in epidermis only Total skin thickness includes the dermis Skin in the back is THIN SKIN, but it is more thicker (dermis included) when compared to palms or soles which are considered THICK SKIN (confused?)  SKIN COLOR Skin pigment Factors that Circulating blood determine skin color Thickness of stratum corneum  SKIN COLOR - Melanin Primarily responsible for skin, hair and eye color MORE melanin = freckles, moles, nipple, areola, axilla, genitalia Provides protection against UV light LESS melanin = lips, palms, soles Produced by melanocytes Irregular shape, with many processes which extends between keratinocytes of s. basale & s. spinosum Melanin are produced and packaged into vesicles (Melanosomes) by melanocytes Melanin production is determined by 1. genetic factors 2. exposure to sunlight 3. hormones Melanin Synthesis Happens in the melanosomes Stage I – immature, unmelanized premelanosomes Stage II – immature, unmelanized premelanosomes Stage III – melanin deposition begins Stage IV – mature melanosomes  SKIN COLOR - Melanin Number of melanocytes are relatively equal in all humans regardless of the race Racial variation determinants: amounts and type of melanin produced / size of melanosomes / number of melanosomes / distribution of melanosomes UV light = stimulated melanin production & darkens the melanin = TANNING ALBINISM = inability to produce TYROSINASE = deficiency/absence of pigments in the skin, hair and/or iris = ALBINO  Abnormal SKIN COLOR Erythema (red) = increase in amount of blood flowing through the skin Inflammatory response (infection/inflammation/allergic reaction/sunburn/others) Flushing/blushing (shy/angry) Pallor (white) = decrease in amount of blood flowing through the skin Cyanosis (blue) = decrease in blood oxygen content Jaundice (yellow) = excess amount of bilirubin circulating in the blood Carotenemia (orange) = accumulation of carotene (found in plants such as carrots and corn) in s. corneum and adipocytes of dermis  SKIN CANCER Mostly a result from damage caused by the UV light form sunlight exposure (long and/or intense exposure) Some are chemically induce, x-ray, immunosuppression, inflammation or inheritance Amount of melanin is a factor Light skinned individual = less melanin = increase risk Dark skinned individual = more melanin = less risk Mostly develop in sub exposed areas (face, neck, ears, dorsum of forearm and hand) Types of UV radiation UVA – (320-400nm) contributes to skin Ca (esp. melanoma), causes wrinkling and leathering of the skin UVB – (290-320nm) most potent for causing sunburn; main cause of BCC & SCC; causes melanoma Recommended SPF (sun protection factor) = at least 15 BASAL CELL CARCINOMA SQUAMOUS CELL CARCINOMA MELANOMA Most common type 2nd most common type Least common Affects stratum basale Affects stratum spinosum Most lethal Varied appearance Varied appearance Arise from melanocyte Open sores that may bleed, Highly metastatic ooze or crust Wart-like growth Reddish patches Persistent, scaly red patch Appearance: Open sore Most are black or brown Shiny/pearly translucent bumps Elevated growth with central May appear skin-colored (pink, red, purple) Scar-like areas of shiny, taut depression skin ≈40% develop from preexisting High cure rate High cure rate moles Rarely metastasize High cure rate if not metastatic  “ABCDE Rule” Early detection and treatment prevents death Asymmetry Sides (½) are unevenly matched Border Irregular, jagged, notched or blurred Color Pigment not uniform Diameter More than 6mm Evolution Lesion changes over time (includes size, shape, elevation, color, bleeding, crusting, tenderness)  DERMIS 2 tissue layers Papillary layer Reticular layer Vascular (nutrient and waste exchange of dermis and deep epidermis Contains nerve endings, hair follicles, smooth muscles, glands & lymphatic vessels Nerve endings (dermis) Meissner Touch, Two point discrimination, low frequency vibration Nerve endings (dermis) Ruffini Continuous touch & pressure, stretch Detects warmth Nerve endings (dermis) Root hair plexus Touch sensation Nerve endings (dermis) Pacinian Deep pressure, vibration, proprioception, Nerve endings (dermis) Krause Detects cold Nerve endings (epidermis) Merkel Disk Light touch Nerve endings (epidermis) Free nerve ending Temperature, mechanical stimuli, nociception  Dermis – PAPILLARY LAYER Superficial Dermal papillae → nipple-like projections toward the epidermis In thick skin, it is responsible for fingerprint & footprint → improves grip and friction Loose connective tissue Vascular (supplies overlying epidermis & aid in regulating body temperature)  Dermis – RETICULAR LAYER Deep Dense irregular connective tissue Resistant to stretch in many directions Main layer of dermis  Dermis – CLEAVAGE LINES aka ‘Langer lines’ or ‘tension lines’ Incision parallel to cleavage lines Less healing time → less prone to infection Less scar tissue formation Incision perpendicular/nonparallel to cleavage lines More healing time → more prone to infection More scar tissue formation  ‘stretch marks’ Visible lines in the skin because of dermal rupture due to overstretching of the skin Can develop during pregnancy (abdomen, breasts) highly observable postpartumly and in weightlifters SUBCUTANEOUS TISSUE aka ‘hypodermis’ / ‘superficial fascia’ Attached skin to underlying muscle and bone Supplies skin with BV and nerves NOT part of the skin Functions as insulator, padding & source of energy SQ tissue amount: babies > women > men  Skinfold thickness Grasp the skinfold firmly between your thumb and index finger of your left hand. The skinfold is lifted 1 cm and recorded with the callipers  INJECTIONS INTRADERMAL SUBCUTANEOUS INTRAMUSCULAR INTRAVENOUS  ACCESSORY SKIN STRUCTURES Hair Glands Sebaceous Sweat Nails  Accessory Skin Structures - HAIR Found everywhere EXCEPT palms, soles, lips, nipples, parts of external genitalia, distal fingers and toes Lanugo delicate unpigmented hair that covers the fetus at 5th to 6th months AOG Lanugo at the scalp, eyebrows & eyelids is replaced by Terminal Hairs (long, coarse, pigmented) near the time of birth; during puberty, terminal hairs Lanugo elsewhere in the body is replaced by Vellus Hair (short, fine, usually unpigmented) near the time of birth Vellus hair at the pubis and axillary regions are replaced by terminal hair at puberty  Hair Structure Divided to: SHAFT = protrusion above the skin ROOT = below the skin Hair bulb = expanded base of the root Mostly compose of columns of dead, keratinized epithelial cells arrange in concentric layers: MEDULLA, CORTEX, CUTICLE Medulla → central axis, 2-3 layers cell containing soft keratin Cortex → surrounds medulla, forms the bulk of the hair, contains hard keratin Cuticle → surrounds the cortex, contains hard keratin, arrange in HAIR FOLLICLE → invagination of the epidermis that extends to the dermis where hair develops and grows Dermal Root Sheath → surrounds epithelial root sheath Epithelial Root Sheath → divides to: External part → has same strata as thin skin (cells decrease towards deeper portions) [deepest portion contains only S. basale] Internal part → protects the growing hair (matrix) HAIR BULB Expanded knob at the base of the root Contains mass of undifferentiated epithelial cells called matrix which produces hair and internal epithelial root sheath HAIR PAPILLA Projection of dermis into the hair bulb Contains blood vessels that nourishes the cells of the matrix  HAIR GROWTH Eyelash Scalp 2 cycles: GROWTH stage & RESTING GROWTH STAGE increase hair length as cells are added at 30 days 3 years stage the base RESTING STAGE 105 days 1-2 years Loss of approx. 100 scalp hair per day is hair growth stops normal → means that the hair is being replaced male pattern baldness – most common kind of permanent hair loss (hair follicle shrink → reverts to vellus hair) Testosterone = hormone involve in causing baldness  HAIR COLOR Melanocyte in the matrix produces melanin BLONDE little eumelanin JET BLACK plenty of eumelanin BROWN intermediate eumelanin varying amount of RED pheomelanin decrease amount of WHITE melanin production EUMELANIN brownish black PHEOMELANIN reddish yellow  HAIR MUSCLE ARRECTOR PILI Smooth muscle (involuntary) Extends from dermal root sheath to papillary layer of the dermis ‘Erects’ the hair when it contracts = GOOSE BUMPS  Accessory Skin Structures– GLANDS (Sebaceous Glands) Simple or compound alveolar glands Holocrine type (shedding, lysis and death, of entire cell) MOSTLY are connected by a duct to the upper part of hair follicles Some (lip, eyelids and genital area) opens directly to the skin surface Produces sebum SEBUM → oily, waxy substance, rich in lipids Prevents hair dryness Protection against some bacteria Accessory Skin Structures– GLANDS (Sweat Glands) aka ‘sudoriferous glands’ 2 types: eccrine & apocrine sweat gland ECCRINE SWEAT GLANDS APOCRINE SWEAT GLANDS Sometimes called ‘merocrine’ Simple, coiled, tubular glands Most common type Usually open into hair follicles (superficial to sebaceous glands) Simple, coiled, tubular glands Found in axilla, scrotum, labia majora and Open directly to skin via SWEAT PORES perianal areas 2 parts: Becomes active at puberty (↑ hormones) Deep coiled portion (located in dermis) DOES NOT help in temperature regulation Duct (passes epidermis to surface) Secretions contain 3-methyl-2-hexemoic acid Produces isotonic fluid (mostly water, some salts [NaCl] & little ammonia, urea, uric & Odorless but quickly metabolized by bacteria resulting to ‘body odor’ lactic acid) NaCl are reabsorb in the ducts of sweat glands Most numerous in the palms and soles  Accessory Skin Structures– GLANDS (Other Glands) Ceruminous Glands Mammary Glands Modified eccrine sweat glands Modified apocrine sweat glands Produces cerumen (earwax) Located in the breast Protects tympanic membrane Produces milk Accumulation may cause impacted cerumen causing hearing impairment  Accessory Skin Structures– NAILS Thin plate of stratum corneum layers Keratin type = HARD Located on distal end of fingers and toes Consist of: NAIL ROOT (covered by skin) & NAIL BODY (visible portion) Grows continuously = no resting phase PHYSIOLOGY OF INTEGUMENTARY SYSTEM Protection Sensation Temperature regulation Vitamin D Synthesis Excretion BURN Classification (based on Classification (based body Classification (Based on depth) surface area/BSA) severity/seriousness) Partial thickness “Rule of 9s” → adult Minor Burn 1st degree burn “Lund & Browder Moderate Burn 2nd degree burn Chart” → children Major Burn Full thickness 3rd degree bur ‘4th degree ‘ burn  Classification (based on depth) PARTIAL THICKNESS FULL THICKNESS 1ST DEGREE (heals ≈1 week) 3RD DEGREE Epidermis (pain, erythema, edema) Complete skin destruction with subcutaneous and/or muscle damage ie: sunburn Often surrounded by 1st/2nd degree burn No scarring Peripheral skin damage is painful, area of 3rd degree 2ND DEGREE burn is painless (destruction of sensory receptors) Epidermis and minimal dermal damage (pain White/tan/brown/black/deep cherry red erythema, edema, blister) → no scarring (heals ≈2 weeks) May appear leathery Epidermis and deep dermal damage Skin graft is necessary (erythema/tan/white) → With scarring (heals in months) 4th DEGREE Most deep (includes tendons and bones) Life-threatening  Classification (based on BSA) RULE OF 9’s LUND & BROWDER For ADULTS For CHILDREN Head & neck = 9% Anterior trunk = 18% Posterior trunk = 18% Left upper extremity = 9% Right upper extremity = 9% Right lower extremity = 18% Right lower extremity = 18% Genitals = 1% BOTH ARE USED TO EXTIMATE THE PERCENTAGE OF BURN AREAS IN THE BODY Classification (based on severity/seriousness) MINOR MODERATE MAJOR 3rd degree burn 10% BSA BSA 2nd degree burn 25% 25% BSA BSA Burn of hands, feet, face, genital or anal regions  THANK YOU! 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