THE INTEGUMENTARY THE INTEGUMENTARY SYSTEMSYSTEM

Chona Araga, M.D.Chona Araga, M.D.

COMPOSED OF:COMPOSED OF:• 1. SKIN1. SKIN

• Heaviest, largest single organHeaviest, largest single organ

• 2.SKIN APPENDAGES:2.SKIN APPENDAGES:

A.sweat glandA.sweat gland

B. sebaceous glandB. sebaceous gland

C. hairsC. hairs

D. nailsD. nails

SKINSKIN• - also called integument- also called integument• - simply means covering- simply means covering

• FUNCTIONS:FUNCTIONS:1.1. Keeps water and other precious Keeps water and other precious

molecules in the bodymolecules in the body2.2. Keeps water outKeeps water out3.3. Protects the body from external agentProtects the body from external agent4.4. Insulates and cushions deeper body Insulates and cushions deeper body

organsorgans5.5. Protects body from mechanical, chemical, Protects body from mechanical, chemical,

thermal damage and also bacteriathermal damage and also bacteria

FUNCTIONSFUNCTIONS• 6. Regulates heat loss from body surface6. Regulates heat loss from body surface

• 7. Acts as mini-excretory system, urea, salt, 7. Acts as mini-excretory system, urea, salt,

water are lost when we sweatwater are lost when we sweat

• 8. Manufactures several proteins important 8. Manufactures several proteins important to to

immunityimmunity

• 9. Storage of Vitamin D precursor9. Storage of Vitamin D precursor

• 10. Contains cutaneous receptors that serve 10. Contains cutaneous receptors that serve as as

sensors for touch, pressure, temperature sensors for touch, pressure, temperature

and painand pain

2 PRINCIPAL LAYERS2 PRINCIPAL LAYERS

• 1. EPIDERMIS1. EPIDERMIS

• 2. DERMIS2. DERMIS

EPIDERMISEPIDERMIS

• Superficial protective layer of the skinSuperficial protective layer of the skin

• avascularavascular

• Composed of Stratified Squamous Keratinized Composed of Stratified Squamous Keratinized Epithelium that varies in thicknessEpithelium that varies in thickness

• All but the deepest layers of epidermis are All but the deepest layers of epidermis are composed of dead cellscomposed of dead cells

• Composed of 4-5 layers, depending on its Composed of 4-5 layers, depending on its location within the bodylocation within the body

• Palms and soles have five layers because Palms and soles have five layers because these areas are exposed to most frictionthese areas are exposed to most friction

• Composed of keratinocytes,nonkeratinocytes Composed of keratinocytes,nonkeratinocytes melanocytes, Langerhans cells and Merkel’s cellsmelanocytes, Langerhans cells and Merkel’s cells

• Constantly being regenerated every 20-30 daysConstantly being regenerated every 20-30 days

• Sequence of cytological changes of keratinocytes Sequence of cytological changes of keratinocytes is referred to as cytomorphosisis referred to as cytomorphosis

• Overlies projection of the dermis (dermal Overlies projection of the dermis (dermal papillae), forming series of epidermal ridgespapillae), forming series of epidermal ridges

• On the fingertips are visible as finger printsOn the fingertips are visible as finger prints

1. Stratum Basale 1. Stratum Basale (germinativum)(germinativum)• Deepest layerDeepest layer

• Composed of single layer of cells in Composed of single layer of cells in contact with the dermiscontact with the dermis

• Cells are cuboidal to columnar Cells are cuboidal to columnar keratinocyteskeratinocytes

• Mitotically activeMitotically active

• Source of cells replacing the shed off Source of cells replacing the shed off superficial layerssuperficial layers

• Attached directly to the basal lamina by Attached directly to the basal lamina by hemidesmosomeshemidesmosomes

• Contains melanocytes and Merkel’s cellsContains melanocytes and Merkel’s cells

Stratum SpinosumStratum Spinosum• Few layers of mitotically active polyhedral Few layers of mitotically active polyhedral

keratinocytes (prickle cell) which have keratinocytes (prickle cell) which have extensions termed intercellular bridges now extensions termed intercellular bridges now known to terminate in desmosomesknown to terminate in desmosomes

• Also contains Langerhan’s cellsAlso contains Langerhan’s cells

• Part of Malphigian layer(stratum malphigii) : Part of Malphigian layer(stratum malphigii) : stratum spinosum and stratum basalestratum spinosum and stratum basale

• Upper aspect of this layer are keratinocytes Upper aspect of this layer are keratinocytes containing membrane coating granulescontaining membrane coating granules– Granules are released into intercellular space in Granules are released into intercellular space in

the form of lipid containing sheets impermeable the form of lipid containing sheets impermeable to water and foreign substancesto water and foreign substances

Stratum GranulosumStratum Granulosum- Consists of only 3-4 flattened Consists of only 3-4 flattened

rows rows

of keratinocytes that contain of keratinocytes that contain keratohyaline granuleskeratohyaline granules, , bundles of keratin filaments and bundles of keratin filaments and occassional monochromatic occassional monochromatic granulesgranules

Stratum Lucidum (Clear Stratum Lucidum (Clear layer)layer)

4-6 rows of very thin, pale-staining, 4-6 rows of very thin, pale-staining, eosinophilic cellseosinophilic cells

•Nuclei,organelles,and cell Nuclei,organelles,and cell membranes membranes are no longer visible are no longer visible so this layer appears clearso this layer appears clear

•Exists only in the lips and the Exists only in the lips and the thickened skin of soles & palmsthickened skin of soles & palms

•Contains a transluscent substance Contains a transluscent substance called eleidincalled eleidin

Stratum CorneumStratum Corneum• 15-20 layers of flattened, scale-like anucleated 15-20 layers of flattened, scale-like anucleated

cells, which arecontinuously shed as flake-like cells, which arecontinuously shed as flake-like residues of cellsresidues of cells

• This surface layer is cornified and is the real This surface layer is cornified and is the real protective layer of the skinprotective layer of the skin

• Cornification is brought on by keratinization and Cornification is brought on by keratinization and the hardening , flattening process that takes place the hardening , flattening process that takes place as the cells die and are pushed to the surfaceas the cells die and are pushed to the surface

• Friction at the surface of skin stimulates additional Friction at the surface of skin stimulates additional mitotic activity of stratum basale, resulting in the mitotic activity of stratum basale, resulting in the formation of a callus for additional protectionformation of a callus for additional protection

• Continuously sheds cells by a process termed Continuously sheds cells by a process termed desquamationdesquamation

Non keratinocytes in Non keratinocytes in epidermis:epidermis:

1. Melanocytes- present in S. basale1. Melanocytes- present in S. basale

- synthesize the pigment melanin - synthesize the pigment melanin providing a protective barrier to UV providing a protective barrier to UV radiation in sunlightradiation in sunlight

2. Langerhan’s cell2. Langerhan’s cell

- located primarily in S. spinosum- located primarily in S. spinosum

- possess long process (ddendritic - possess long process (ddendritic cells), originate from monocytescells), originate from monocytes

- contain characteristic paddle-- contain characteristic paddle-shaped shaped Birbeck granulesBirbeck granules

-- antigen presenting cells antigen presenting cells

c) Tactile cells ( Merkel cell)c) Tactile cells ( Merkel cell) - present in small number in - present in small number in S. basale S. basale

- possess desmosomes and - possess desmosomes and keratin keratin filaments filaments

- pale cytoplasm containing - pale cytoplasm containing small, small, dense-cored granules dense-cored granules - - aid in tactile (touch) receptionaid in tactile (touch) reception

COLORATION OF SKINCOLORATION OF SKIN

• . CAUSED BY EXPRESSION OF A . CAUSED BY EXPRESSION OF A COMBINATION OF 3 PIGMENTSCOMBINATION OF 3 PIGMENTS

1.1.MELANINMELANIN

2.2.CAROTENECAROTENE

3.3.HEMOGLOBINHEMOGLOBIN

MELANINMELANIN

•Brown-black pigment produced by Brown-black pigment produced by the melanocytes of stratum basalethe melanocytes of stratum basale

•Guards skin against damaging effect Guards skin against damaging effect of UV rays of sunlightof UV rays of sunlight

•Gradual exposure to sunlight Gradual exposure to sunlight promotes increased production of promotes increased production of melanin; hence tanning of skinmelanin; hence tanning of skin

• In albino, there is a normal number of In albino, there is a normal number of melanocytes but lacks enzyme melanocytes but lacks enzyme tyrosinase, that converts the amino acid tyrosinase, that converts the amino acid tyrosine to melanintyrosine to melanin

• ““freckles”- caused by aggregated patch of freckles”- caused by aggregated patch of melaninmelanin “ “vitiligo”- lack of melanocytes in localized vitiligo”- lack of melanocytes in localized

areas of the skin causing distinct white areas of the skin causing distinct white spotsspots

2. CAROTENE2. CAROTENE - a yellowish pigment found in epidermal - a yellowish pigment found in epidermal

cells & cells & fatty parts of dermisfatty parts of dermis - abundant in skin of Asians- abundant in skin of Asians - together with melanin, accounts for the - together with melanin, accounts for the yellowish-tan color of Asiansyellowish-tan color of Asians

3.3. HEMOGLOBIN HEMOGLOBIN

•Not a pigment of the skin, rather Not a pigment of the skin, rather it is the oxygen-binding pigment it is the oxygen-binding pigment found in RBcfound in RBc

•Oxygenated blood flowing Oxygenated blood flowing through the dermis gives the skin through the dermis gives the skin its pinkish tonesits pinkish tones

DERMISDERMIS

• Deeper and thicker than the epidermisDeeper and thicker than the epidermis

• A strong and stretchy envelope that helps to A strong and stretchy envelope that helps to hold the body togetherhold the body together

• Blood vessels within the dermis nourish the Blood vessels within the dermis nourish the living portion of the epidermisliving portion of the epidermis

• With numerous collagenous, elastic and With numerous collagenous, elastic and reticular fibers that give support to the skinreticular fibers that give support to the skin

• Highly vascular and glandularHighly vascular and glandular

• Contains many nerve endings and hair Contains many nerve endings and hair folliclesfollicles

Layers of DermisLayers of Dermis1.1.PAPILLARY LAYERPAPILLARY LAYER

- in contact with epidermis- in contact with epidermis

- Accounts for about 1/5 of the entire - Accounts for about 1/5 of the entire

dermisdermis

- With numerous projections called Dermal - With numerous projections called Dermal Papillae, that extend from the upper Papillae, that extend from the upper portion of the dermis into the epidermisportion of the dermis into the epidermis

- Dermal papillae contain capillary loops, - Dermal papillae contain capillary loops, which furnish nutients to the epidermiswhich furnish nutients to the epidermis

- - Some papillae house pain Some papillae house pain receptors (free nerve receptors (free nerve endings) and touch endings) and touch receptors (meissner’s receptors (meissner’s corpuscles)corpuscles)

- Dermal papillae form the - Dermal papillae form the base for the friction ridges base for the friction ridges on the fingers and toeson the fingers and toes

•Reticular layerReticular layer– Deepest skin layerDeepest skin layer– Contains blood vessels, sweat & oil Contains blood vessels, sweat & oil

glands, and deep pressure glands, and deep pressure receptors (Pacinian Corpuscles)receptors (Pacinian Corpuscles)

– Many phagocytes are found here; Many phagocytes are found here; they engulf bacteria that have they engulf bacteria that have managed to get through the managed to get through the epidermisepidermis

– May contain Pacinian corpuscles May contain Pacinian corpuscles and Krause’s end bulbs and Krause’s end bulbs

Thick and Thin Thick and Thin SkinSkin

Thick skin (glabrous Thick skin (glabrous skin)skin)

• 400-600um thick400-600um thick

• Prominent Prominent S.corneum,well S.corneum,well developed S. developed S. granulosum and granulosum and distinct S. lucidumdistinct S. lucidum

• Lacks hair Lacks hair follicles,sebaceous follicles,sebaceous glands and arrector glands and arrector pilipili

Thin skin (hairy Thin skin (hairy skin)skin)

75-100 um thick75-100 um thick

Less prominent Less prominent corneum lacks corneum lacks granulosum and granulosum and lucidumlucidum

With hair follicles With hair follicles sebaceous glands sebaceous glands and arrector piliand arrector pili

SURFACE PATTERNSSURFACE PATTERNS

• 1. 1. CONGENITAL PATTERNSCONGENITAL PATTERNS

+ fingerprints or friction ridges+ fingerprints or friction ridges

- present on palms and soles- present on palms and soles

- formed by the pull of elastic fibers - formed by the pull of elastic fibers

within the dermiswithin the dermis

- function to prevent slippage when - function to prevent slippage when

grasping objectsgrasping objects

2. ACQUIRED LINES2. ACQUIRED LINES

• Deep Flexion CreasesDeep Flexion Creases - found on the palms- found on the palms Shallow Flexion LinesShallow Flexion Lines - seen on knuckles and surface of other - seen on knuckles and surface of other

jointsjoints

Furrows in the forehead and face (wrinkles)Furrows in the forehead and face (wrinkles) - acquired from continual contraction of - acquired from continual contraction of

facial muscles, such as from smiling or facial muscles, such as from smiling or squinting in bright light or against the wind; squinting in bright light or against the wind; facial lines become more strongly delineated facial lines become more strongly delineated as one agesas one ages

Lines of tension produced by the Lines of tension produced by the orientation of collagen and elastic fibers orientation of collagen and elastic fibers in nonrandom pattern of arrangementin nonrandom pattern of arrangement

Linear wound oriented parallel to langer Linear wound oriented parallel to langer lines tend to close and heal with lines tend to close and heal with minimum scarring, even if left unsuturedminimum scarring, even if left unsutured

Linear wounds oriented perpendicular to Linear wounds oriented perpendicular to langer lines tend to gape and heal slowly langer lines tend to gape and heal slowly with consipicuous scarring if left with consipicuous scarring if left unsuturedunsutured

LANGER LINESLANGER LINES

• Beneath the dermis lies the Beneath the dermis lies the hypodermishypodermis (Gr. (Gr. hypo,hypo, under, + under, + derma,derma, skin), or skin), or subcutaneous subcutaneous tissue,tissue, a loose connective tissue that a loose connective tissue that may contain a pad of adipose cells, the may contain a pad of adipose cells, the panniculus adiposus.panniculus adiposus.

• The hypodermis, which is not The hypodermis, which is not considered part of the skin, binds skin considered part of the skin, binds skin loosely to the subjacent tissues and loosely to the subjacent tissues and corresponds to the superficial fascia of corresponds to the superficial fascia of gross anatomy.gross anatomy.

CUTANEOUS GLANDSCUTANEOUS GLANDS

• 1. SEBACEOUS (OIL) GLANDS1. SEBACEOUS (OIL) GLANDS

- found all over the skin, except on palms and - found all over the skin, except on palms and solessoles - ducts usually empty into a hair follicle but - ducts usually empty into a hair follicle but some open directly onto skin surfacesome open directly onto skin surface - secretion is called sebum, a mixture of oily - secretion is called sebum, a mixture of oily substance and fragmented cells that keep skin substance and fragmented cells that keep skin soft and moist and prevents hair from soft and moist and prevents hair from becoming brittlebecoming brittle

• - - if the drainage pathway for if the drainage pathway for sebaceous glands becomes blocked sebaceous glands becomes blocked for some reason, the glands may for some reason, the glands may become infected, resulting in acnebecome infected, resulting in acne

•- sebum also contains chemicals that - sebum also contains chemicals that kill bacteriakill bacteria

•- become very active when sex - become very active when sex hormones are produced in increased hormones are produced in increased amounts during adolescence, thus amounts during adolescence, thus skin is oilier during this period of lifeskin is oilier during this period of life

• SWEAT GLANDS SWEAT GLANDS

- also called sudoriferous glands- also called sudoriferous glands

- widely distributed in the skin; numerous - widely distributed in the skin; numerous in palms, soles, axillary and pubic in palms, soles, axillary and pubic regionsregions

- secretion evaporates and cools in the - secretion evaporates and cools in the bodybody

22 TYPES:TYPES:

1. Eccrine1. Eccrine

2. Apocrine2. Apocrine

ECCRINE SWEAT GLANDECCRINE SWEAT GLAND

• - - more numerous and found all over more numerous and found all over the body especially in forehead, the body especially in forehead, back, palms and solesback, palms and soles

• Innervated by cholinergic fibersInnervated by cholinergic fibers

•Secretion reaches skin surface via a Secretion reaches skin surface via a duct that opens directly on surface of duct that opens directly on surface of skin through sweat poresskin through sweat pores

•Secretion is mostly water with few Secretion is mostly water with few saltssalts

Secretory unit composed of:Secretory unit composed of:

• 1. dark cells – secrete mucus-rich material1. dark cells – secrete mucus-rich material

• 2. clear cells – secrete a watery, 2. clear cells – secrete a watery, electrolyte rich materialelectrolyte rich material

• 3. myoepithelial cells – contract and aid 3. myoepithelial cells – contract and aid nin expressing the gland’s secretion into nin expressing the gland’s secretion into the ductthe duct

• Ductal unit is narrow and lined by Ductal unit is narrow and lined by stratified cuboidal epitheliumstratified cuboidal epithelium

2. APOCRINE SWEAT GLANDS2. APOCRINE SWEAT GLANDS• - - much larger, localized gland found in much larger, localized gland found in

axillary and pubic regions where they axillary and pubic regions where they secrete into hair folliclessecrete into hair follicles

• Not functional until pubertyNot functional until puberty

• Responsive to hormonal influenceResponsive to hormonal influence

• Secretion is thick and rich in organic Secretion is thick and rich in organic substances which is odorless when substances which is odorless when released but quickly broken down by released but quickly broken down by bacteria into substances responsible for bacteria into substances responsible for body odorbody odor

• Innervated by adrenergic fibersInnervated by adrenergic fibers

MAMMARY GLANDMAMMARY GLAND

•Found within the breastsFound within the breasts

•Specialized sudoriferous or Specialized sudoriferous or sweat gland that secrete sweat gland that secrete milk during lactationmilk during lactation

•Under the stimulus of Under the stimulus of pituitary glandpituitary gland

ADIPOSEADIPOSE

HAIRHAIR• An invagination of the epidermisAn invagination of the epidermis

• Characteristic of all mammals, but its Characteristic of all mammals, but its distribution, function, density and texture distribution, function, density and texture varies across mammalian speciesvaries across mammalian species

• Humans are relatively hairless, with only the Humans are relatively hairless, with only the scalp, face, pubis & axilla being densely scalp, face, pubis & axilla being densely hairedhaired

• Men with more obvious hair because of the Men with more obvious hair because of the male hormonemale hormone

• Certain regions of body are hairless like the Certain regions of body are hairless like the palms, soles, lips, nipples, penis,labia minorepalms, soles, lips, nipples, penis,labia minore

• Lifespan 3-4 mos for eyelashes, 3-4 yrs-scalpLifespan 3-4 mos for eyelashes, 3-4 yrs-scalp

Primary Function of Hair: Primary Function of Hair: ProtectionProtection

e.g. scalp hair, eyebrows- protect e.g. scalp hair, eyebrows- protect from sunlightfrom sunlight

• PARTS OF HAIR:PARTS OF HAIR:1. Shaft – the visible but dead portion of 1. Shaft – the visible but dead portion of hair projeting above surface of the skinhair projeting above surface of the skin

• Consists of medulla,cortex and cuticleConsists of medulla,cortex and cuticle

• 2. Root – enclosed in the follicle2. Root – enclosed in the follicle

• 3. Bulb – terminal expanded region in 3. Bulb – terminal expanded region in which hair is rootedwhich hair is rooted

• Deeply indented by a dermal papilla Deeply indented by a dermal papilla which contains capillary loops for which contains capillary loops for nutritionnutrition

• Contains cells that form internal root Contains cells that form internal root sheath and medullasheath and medulla

• 1. Internal root sheath – deep to the 1. Internal root sheath – deep to the entrance of sebaceous glandsentrance of sebaceous glands

• Composed of Henle’s layer, Huxley’s Composed of Henle’s layer, Huxley’s layer and cuticlelayer and cuticle

• 2. External root sheath2. External root sheath

• - direct continuation of the S. malphigii- direct continuation of the S. malphigii

• Glassy membrane – noncellular layerGlassy membrane – noncellular layer

• Separates the hair follicle from the Separates the hair follicle from the surrounding dermal sheathsurrounding dermal sheath

3 DISTINCT KINDS OF HAIR IN 3 DISTINCT KINDS OF HAIR IN HUMANSHUMANS

• 1. LANUGO – 1. LANUGO – - fine, silky fetal hair that appears - fine, silky fetal hair that appears

during the last trimester of developmentduring the last trimester of development - Usually not evident on a baby at - Usually not evident on a baby at

birth unless it has been born prematurelybirth unless it has been born prematurely

2. ANGORA2. ANGORA - grows continuously in length, as on - grows continuously in length, as on

scalp and on face of malesscalp and on face of males

• 3. DEFINITIVE3. DEFINITIVE

- grows to a certain length and then - grows to a certain length and then ceases to grow ceases to grow

- most dominant type of hair- most dominant type of hair

e.g. eyelashes, eyebrow,pubic, and e.g. eyelashes, eyebrow,pubic, and axillary hairaxillary hair

- A sebaceous gland and an arrector pili A sebaceous gland and an arrector pili muscle are attached to the hair folliclemuscle are attached to the hair follicle

- When the muscle involuntarily contracts When the muscle involuntarily contracts due to thermal or psychological stimuli, due to thermal or psychological stimuli, the hair follicle is pulled into an upright the hair follicle is pulled into an upright position, causing the hair to”stand on its position, causing the hair to”stand on its end” and producing goosebumpsend” and producing goosebumps

NAILSNAILS

• Found on distal dorsum of each fingers Found on distal dorsum of each fingers andand

toestoes

- Forms from a hardened, transparent, Forms from a hardened, transparent, stratum corneum of epidermisstratum corneum of epidermis

- Consists of:Consists of:

- Nail BodyNail Body

- visible attached portion- visible attached portion

- Nail RootNail Root

- part of the nail covered by skin- part of the nail covered by skin

Nail BedNail Bed- where nail root and nail body - where nail root and nail body are attached are attachedFree edgeFree edge - the distal exposed border - the distal exposed border attached to undersurface of attached to undersurface of hyponychium hyponychiumHyponychiumHyponychium - beneath the free edge - beneath the free edge

Eponychium ( Cuticle)Eponychium ( Cuticle) - covers the nail root - covers the nail root - frequently splits causing a - frequently splits causing a hangnail hangnailNail MatrixNail Matrix - proximal part of the nail bed - proximal part of the nail bed - growth area of the nail - growth area of the nailLunulaLunula -whitish crescent (half moon) -whitish crescent (half moon) shaped area at the shaped area at the proximal aspect of nail proximal aspect of nail

-Fingernails grow at -Fingernails grow at approximately 1 mm per approximately 1 mm per weekweek

- Growth of toenails is slower- Growth of toenails is slower- nails are transparent and - nails are transparent and nearly colorless but they look nearly colorless but they look

pink because of the rich blood pink because of the rich blood supply in the underlying supply in the underlying dermis dermis

Thank YouThank You