CHAPTER 6

INTEGUMENTARY SYSTEM

 SKIN  Largest organ by weight  ACCESSORY STRUCTURES

SKIN

 FUNCTIONS:  MAINTAIN HOMEOSTASIS  PROTECTIVE COVERING  PREVENT WATER LOSS  REGULATE BODY TEMPERATURE  SENSE RECEPTORS  SYNTHESIZES CHEMICALS  IMMUNE SYSTEM CELLS  EXCRETES SOME WASTE

CUTANEOUS MEMBRANE

 EPIDERMIS  STRATIFIED SQUAMOUS EPITHELIUM  DERMIS  THICKER  CONNECTIVE TISSUE: DENSE IRREGULAR; AREOLAR; SMOOTH MUSCLE; NERVOUS TISSUE; BLOOD BASEMENT MEMBRANE: SEPARATES BOTH

SUBCUTANEOUS LAYER HYPODERMIS

 AREOLAR AND ADIPOSE TISSUE  BINDS TO UNDERLYING ORGANS  FIBERS CONTIGUOUS WITH DERMIS  INSULATION:  CONSERVE HEAT?

 MAJOR BLOOD VESSELS  RETE CUTANEUM

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EPIDERMIS

 STRATIFIED SQUAMOUS  NO BLOOD VESSELS  LAYERS:  STRATUM BASALE (STRATUM GERMINATIVUM/ BASAL CELL LAYER)  STRATUM SPINOSUM  STRATUM GRANULOSUM  STRATUM LUCIDUM  STRATUM CORNEUM

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STRATUM BASALE

 LIVING: DIFFUSION  MITOSIS  NUCLEI  SINGLE ROW OF CUBOIDAL  MELANOCYTES

STRATUM SPINOSUM

 MANY LAYERS  LARGE, CENTRAL, OVAL NUCLEI  KERATIN FIBERS FORMING  CELLS STARTING TO FLATTEN

STRATUM GRANUSLOSUM

 3-5 LAYERS  FLATTENED GRANULAR CELLS  KERATIN  SHRUNKEN NUCLEI

STRATUM LUCIDUM

 IN THICKEST SPOTS: PALMS, SOLES  CLEAR CELLS: NUCLEI, ORGANELLES CAN’T BE SEEN

STRATUM CORNEUM

 DEAD  KERATINIZED  DESMOSOMES  NONNUCLEATED  SQUAMOUS

EPIDERMAL HOMEOSTASIS

 RUBBED OFF CELLS = MITOSIS  INCREASES IN AREAS OF HEAVIER WEAR  CALLUSSES, CORNS

EPIDERMAL FUNCTIONS

 PROTECTION:  PREVENTS WATER LOSS  AGAINST MECHANICAL FORCE  AGAINST HARMFUL CHEMICALS  PREVENTS ENTRANCE OF PATHOGENS

MELANOCYTES

 MELANOSOMES PRODUCE MELANIN FROM TYROSINE  SKIN COLOR  ABSORBS UV RADIATION  IN STRATUM BASALE BUT CELLULAR EXTENSIONS (PROCESSES) ALLOW MELANIN TO PASS TO KERATINOCYTES  KERATINOCYTES SEEM TO STIMULATE MELANOCYTES TO RELEASE MELANIN

SKIN COLOR

        GENETICS & ENVIRONMENT SAME NUMBER OF MELANOCYTES BUT DIFFER IN HOW MUCH MELANIN IS PRODUCED DARK SKIN: MORE MELANIN; SINGLE, LARGE PIGMENT GRANULES LIGHTER SKIN: SMALLER AND 2-4 GRANULES ALBINISM: NO PIGMENT SUNLIGHT, UV AND X-RAYS INCREASE PRODUCTION OF MELANIN: FADES OXYGENATED BLOOD IN SKIN: LOTS OF BLOOD= PINK CYANOSIS: LOW O2: DARK RED HEMOGLOBIN

DERMIS

 DERMAL PAPILAE ?

 FINGERPRINTS  BINDS EPIDERMIS  DENSE IRREGULAR CONNECTIVE TISSUE  1-2 MM (.5MM-3.0MM)  SMOOTH MUSCLE; SKELETAL MUSCLE  NERVE CELL PROCESSES: SENSORY AND MOTOR  SENSE RECEPTORS ( CHAP 12 )

ACCESSORY STRUCTURES

 NAILS  NAIL PLATE, NAIL BED- SPECIALIZED EPITHELIAL CELLS  LUNULA- MITOSIS-TINY KERATINIZED SCALES

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HAIR FOLLICLES

 GROWTH CYCLE: 2-6 YEARS, REST, FALLS OUT, REPLACED  ON MOST SURFACES BUT NOT ALL AS DEFINED  HAIR FOLLICLE: EPIDERMAL CELLS AT BASE, HAIR ROOT: NOURISHED BY DERMAL BLOOD VESSELS  MOVE UP, KERATINIZE, DIE = HAIR SHAFT  BALDNESS: GENETIC DOMINANT/RECESSIVE

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HAIR COLOR

 GENES DETERMINE PIGMENT TYPE AND AMOUNT  MELANOCYTES:  EUMELANIN: DARK HAIR  PHEOMELANIN BLONDE, RED  TRICHOSIDERIN: RED  NO PIGMENT: WHITE  MIX OF WHITE AND PIGMENTED: GRAY: SOME INTERMEDIATE COLOR = GRAY

ARRECTOR PILI MUSCLE

 ON EACH HAIR FOLICLE: GOOSE BUMPS  SMOOTH MUSCLE  INVOLUNTARY

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SEBACEOUS GLANDS

       SPECIALIZED GLANDULAR EPITHELIAL CELLS ASSOCIATED WITH HAIR FOLLICLES: PILOSEBACEOUS UNIT BRANCHED ACINAR GLAND HOLOCRINE: FATTY MATERIAL: SEBUM: BURSTS CELL: LIPID, WAX, CELL DEBRIES INTO HAIR FOILLICLE; SOME TO SWEAT PORES (AREAS WITHOUT HAIR) KEEPS HAIR AND SKIN SOFT, PLIABLE AND WATERPROOF SCATTERED; NOT ON PALMS, SOLES; NOT ALL WITH FOLLICLES SPECIALIZED: MEIBOMIAN GLANDS: SECRETION SLOWS EVAPORATION OF TEARS

          

SWEAT GLANDS

SUDORIFEROUS GLANDS WIDESPREAD BALL IN DERMIS OR SUBCUTANEOUS SPECIALIZED GLANDULAR EPITHELIAL CELLS MOST NUMEROUS/ FOUND IN MOST AREAS: ECCRINE: RESPOND TO INCREASED BODY TEMPS ARE MEROCRINE: ODORLESS; MOSTLY H2O AND SALT, A LITTLE UREA CONTROLLED BY SYMPATHETIC NERVOUS SYSTEM APOCRINE GLANDS: ARE ACTUALLY MEROCRINE MORE VISCOUS FLUID; DEVELOP SCENT FROM SKIN BACTERIA; ACTIVATED AT PUBERTY IN ARMPITS, AREOLA, GENITALANAL AREA; HAIR FOLLICLES STIMULATED BY ADRENALINE

 MODIFIED SWEAT.T GLANDS: CERUMINOUS GLANDS AND MAMMARY GLANDS

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REGULATION OF BODY TEMPERATURE

 HOMEOSTASIS: HEAT PRODUCED= HEAT LOST  HEAT PRODUCTION:  CELLULAR RESPIRATION  SET POINT IN:  HYPOTHALAMUS:  VASODILATION/VASOCONSTRICTION  HEART

HEAT LOSS

    RADIATION:   MAJOR PROCESS; INFRARED CONDUCTION:  TO COOLER OBJECT IN CONTACT (CHAIR/AIR) CONVECTION:  WARMER AIR MOVES AWAY AND COOLER AIR IS THEN HEATED EVAPORATION:   ECCRINE SWEAT GLANDS RELEASE SWEAT EVAPORATES AND CARRIES HEAT AWAY

HEAT RETENTION

 VASOCONSTRICTION:  STOPS RADIATION, CONDUCTION, CONVECTION,  SWEAT GLANDS INACTIVE  STOPS EVAPORATION  CONTRACTION OF MUSCLES WHICH COULD LEAD TO SHIVERING

HEAT REGULATION PROBLEMS

  HOT, HUMID DAY:    NO EVAPORATION HYPERTHERMIA IF HOTTER THAN BODY TEMP MAY GAIN HEAT FROM ENVIRONMENT PROLONGED COLD EXPOSURE/SICKNESS:      HYPOTHERMIA SHIVERING MENTAL CONFUSION, LETHARGY, LOSS OF REFLEXES, LOSS OF CONSCIOUSNESS, MAJOR ORGANS SHUT DOWN, DEATH BODIES CORE CAN ONLY DROP A FEW DEGREES, EXTREMETIES CAN SURVIVE DROPS TO 20-30° F RISK: HOMELESS, AGED, YOUNG, VERY THIN

HEALING

 INFLAMMATION:  BLOOD VESSELS DILATE AND INCREASE PERMEABILITY: EDEMA  BECOME: RED, SWOLLEN, HOT, PAINFUL ?

 BENEFIT:  PROVIDE MORE O 2 AND NUTRIENTS

 

HEALING CUTS

SHALLOW:  EPITHELIAL CELLS INCREASE MITOSIS DEEP:      BLOOD VESSEL CUT: CLOTTING FIBRIN FORMED FROM ANOTHER BLOOD PROTEIN WHICH TRAPS PLATELETS DRIES: SCAB EPITHELIAL CELLS REPLICATE FIBROBLASTS MOVE IN AND SECRETE COLLANGENOUS FIBERS      CONNECTIVE TISSUE MATRIX RELEASES GROWTH FACTORS INCREASE MITOSIS BLOOD VESSELS EXTEND IN PHAGOCYTES REMOVE DEAD CELLS AND DEBRIS SCAB SLOUGHS OFF SCAR COULD FORM

SCAR

 TOO WIDE  GRANULATIONS FORM:  NEW BLOOD VESSEL AND FIBROBLASTS  SECRETE COLLAGENOUS FIBERS  BLOOD VESSELS ARE RESORBED, FIBROBLASTS MOVE  SCAR IS MOSTLY COLLAGENOUS FIBERS

BURNS

  1 ST  DEGREE: PARTIAL THICKNESS: ONLY EPIDERMIS; REDNESS, MILD EDEMA,MAY SHED;   2 ND MILD SUNBURN HEALS QUICKLY, NO SCARRING DEGREE:    DEEP PARTIAL THICKNESS: EPIDERMIS AND SOME DERMIS;FLIUID LEAKS FROM CAPILLARIES: BLISTERS; DARK RED TO WAXY WHITE; HOT OBJECTS OR LIQUIDS, FLAMES, BURNING CLOTHES; HEALING DEPENDS ON EPIDERMAL STEM CELLS IN ACCESSORY STRUCTURES OF DERMIS ?; NO SCARRING UNLESS INFECTED

BURNS

 3 RD DEGREE: FULL THICKNESS:   DESTROYS EPIDERMIS, DERMIS AND ACCESSORY STRUCTURES; LEATHERY, RED TO WHITE OR BLACK; IMMERSION IN HOT LIQUIDS, PROLONGED EXPOSURE TO HOT OBJECTS, FLAMES OR CORROSIVE CHEMICALS;  SCARRING; GRAFTING MAY BE NEEDED: WHY?

   AUTOGRAFT ALLOGRAFT (MUST BE REPLACED) SKIN SUBSTITUTES AMNIOTIC MEMBRANE, ARTIFICIAL MEMBRANES, CULTURED EPITHELIAL CELLS,

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LIFE SPAN CHANGES

   EPIDERMIS:  MITOSIS SLOWS: LARGER, IRREGULAR BUT LESS; SCALY: KERRATIN BONDS; ‘AGE SPOTS’ FROM OXIDATION OF GLANDS; DERMIS:  FIBER PRODUCTION SLOWS: THINS; WITH LOSS OF ADIPOSE (SUBCUTANEOUS): WRINKLING; HEALING SLOWWS (LESS FIBROBLASTS); OIL PRODUCTION DECREASES: SKIN DRIES; ACCESSORY GLANDS:  LESS MELANIN: WHITE HAIR; HAIR GROWTH SLOWS, HAIRS THIN, FOLLICLE NUMBER DECREASES, BALDNESS (MALES); LESS BLOOD TO NAILS: SLOWS GROWTH, HARDEN; LESS PAIN AND PRESSURE RECEPTORS;

LIFE SPAN CHANGES (CONT.)

 TEMPERATURE CONTROL LESSENS: LESS SWEAT GLANDS AND LESS CAPILLARIES TO GLANDS; SHIVERING ABILITY LESSENS; LESS DEEPER BLOOD VESSELS AND LESS ABILITY TO SHUNT BLOOD TO INTERIOR: FEEL COLD; PALE: LESS BLOOD VESSELS IN SKIN; BED SORES: CHANGES IN BLOOD VESSELS;  GET LESS VITAMIN D AND GET OUTSIDE LESS: AFFECTS BONE MAY NEED SUPPLEMENTAL VITAMIN D;

THINGS TO KNOW

 What is the integumentary system? The parts, membrane type, functions .

 Layers, what is found there, functions  Layers of epidermis: what is present, purpose, melanocytes,  What determines skin color  Accessory structures: nails, hair, oil glands, sweat glands  How body temperature is regulated, heat is lost, retained, problems with regulation

 How healing occurs in the different layers, scar formation  Characteristics of different types of burns, healing, grafting  Life span changes: epidermis, dermis, accessory glands, temperature control