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
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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
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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,
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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
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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
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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 O2 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
 1ST DEGREE:
 PARTIAL THICKNESS: ONLY EPIDERMIS; REDNESS, MILD
EDEMA,MAY SHED;
 MILD SUNBURN
 HEALS QUICKLY, NO SCARRING
 2ND 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
 3RD 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?
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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,
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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