THE INTEGUMENTARY SYSTEM Skin and its Derivatives
Nov 02, 2014
THE INTEGUMENTARY SYSTEM
Skin and its Derivatives
DERMATOLOGYSTUDY OF THE STRUCTURE,
COMPOSITION, AND FUNCTIONS OF THE SKIN
DERMA- SKIN
SKIN/INTEGUMENT – the largest organ of the body, approximately 5 kg of the body weight
thick in palms and soles, thin in eyelids and scrotum
Functions of SkinProtects from injuriesActs as barrier and regulates what
enters/leaves body.Regulates body temperature.Synthesizes, stores vitamins.Sensory functionsExcretionAbsorption
Main layers of the Skin1. Epidermis – outermost skin layer
2.Dermis – true skin layer
3. Hypodermis – the subcutaneous layer
DIFFERENCES OF THE SKIN LAYERSBASIS EPIDERMIS DERMIS HYPODERMIS
1. LOCATION OUTERMOST SUB EPIDERMAL SUBCUTANEOUS
2.THICKNESS THIN THICK RELATIVE
3. HISTOLOGICAL COMPONENT
HIGHLY EPITHELIAL CONNECTIVE, MUSCULAR,NERVOUS,VASCULAR
CONNECTIVE
4. VASCULARI- ZATION
AVASCULAR VASCULAR VASCULAR
5. LAYERS 5 SUB LAYERS
1.S. CORNEUM2.S. LUCIDUM3.S. GRAULOSUM4. S. SPINOSUM5. S. GERMINATIVUM
2 SUB LAYERS
1.S. PAPILLAROSUM
2.S. RETICULAROSUM
RELATIVE
6. NERVE ENDINGS ABSENT PRESENT PRESENT
7. GLANDS AGLANDULAR GLANDULAR –SWEAT,SEBACEOUS,MAMMARY
GLANDULAR – SECRETES LEPTIN
8. DERIVATIVES HAIRS AND NAILS GLANDS GLAND
EPIDERMAL DIFFERENCES
I.Epidermis of fishes and Aquatic amphibians
GLANDS1.MUCOUS GLANDSsecretes gelatinous substance mucinin frogs; for water absorption and
respirationin fish; defense mechanism for predations
2.SEROUS GLANDS-secretes poisonous alkaloids for protection against predators.
3.PHOTOPHORES GLANDS-contains light-emittingn
II.EPIDERMIS OF TERRESRIAL OR LAND VERTERATES
GLANDS1.MAMMARY GLANDSsecretes milk-feed the youngboth sexes;male-non functional;female-
location
2.SWEAT GLANDS AND SUDORIFEROUS GLANDS
produce sweat/perspiration cooling mechanism to regulate body temp
3.OIL/ SEBACEOUS GLANDSsecretes oilo/sebum;for lubrication/mare skin moist/shiny
4.UROPYGIAL GLAND [BIRDS]tail of uroryogiumsecretes oil,oiling the beark;shiny feathers/preening by beaks
5.SEROUS GLANDS [SNAKE]secretes poison/toxic alkaloids
6.CERUMINOUS GLANDS [MAN]-secretes cerumen
7.GLANDS OF ZELS-moits the eyelashes
8.MELBOMIAN GLANDS-moists the eyelids
TYPES OF GLANDS ACCDG. TO MANNER OF SECRETION1.MEROCRINE GLANDS [TRUE GLAND]release secretion thought
memrbrane/cells remain intact.ex.unicellular integumentary glands sweat
glands2.HOLOCRINE GLANDScells themselves constitute the secretioncells goes with secretionex.sebaceous gland
APOCRINE SWEAT GLAND
3.APOCRINE GLANDSintermediate in positionsecretions gathers at the tip or apical portion of the cell
part of the cyptoplasm are pinched off with the secretion & then repair itself.
ex.mammary glands
EPIDERMAL DERIVATIVES
1.MAMMALSHAIR- shaft,bulb,rootNAILS-lunula,nail bed,rootCLAWS-cats,monkeys,bird,etc,HOOVES-ungulatesTUSKS-elephants,source of plastics
2.BIRDS-BEAKS,PREENING,NESTING,F00D-FEATHERS-FOR INSULTION,FLIGHTS,BODY CONTOURS
parts;shaft,barbs,barbules,,calamusTypes;1.flight feathers2.covert feathers3.pin feathers4.filoplumers5.hair feathers
3.REPTILESepidermal scales-moltingExoskeleton turtles-scutes -corapace - plastron
4.AMPHIBIAN-rough/coarse skin
5.FISHES –with dermal scales
Types of scales1.CYCLOID SCALES-concentric ridges-milkfish2.CTENOID SCALES-w/spines or ctenii3.GANIOD SCALES-rhomboid shape,4.COMOID SCALES-extinct fishes dermal armor5.PLACOID SCALES-spines directed caudally-sharks,skates
COMPARATIVE ANATOMY OF THE SKINCHORDATE EPIDERMIS DERMIS
1. AGNATHANS ‘multi-layered and is rich w/mucous glands
‘slime eels lack scales
‘Layers are mitotic including surface cells horny denticles in the buccal funnel is the only cormfied structure,shed replaced
‘thinner than epidermis but tough due to interwoven collagenous fibers.
‘rich in the melanophores w/c ad heres tightly to the underlying musculator myosepta
CHORDATE EPIDERMIS DERMIS
2.CHONDRICH-THYES
‘more layered and cells are compactly arranged
‘unicellular glands excepting chaemiras
‘stingrays-goblet toxins.
‘multicellular cells at the base secretes toxins
Multicelullar cells are conc. at the base of the claspers of males
‘thicker than epidermis and w/2 more or less defined layers
‘placoid scales fr.the paleozioc shakers
‘sheet of melanophores derse dorsally than virtrally less illumnuscence
‘with ceratotrichia or fin rays
CHORDATE EPIDERMIS DERMIS
3. OSTEICH-THYES
-more mucous glands
-presence of cycloid scales
-with uicellular goblet cells w/c maintain mucous coat of the skin to prevent dessication
-with poisonous granular gland
-photophores serve as lures /warning
-presence of ancient ganoid or modern cycloid scale
-flexible dermal fin rays which stregthens the fins of bony fishes
-with osteoderms
Bony fish
CHORDATE EPIDERMIS DERMIS
4.AMPHIBIA ‘skin-w/o scales
‘with incipient stratum corneum
‘uncellular goblet cells secretes mucigens for semi-aquatic amphibians
‘mucons glands-mucin
‘poison glands-alkaloidal secreation
‘cornified skin prevents dessication.
‘with dermal chomatophores
‘firmly attached to the underlying musuculature
‘voluminous bread subcutaneous lymph sinuses separates skin from muscles
‘bony dermal scales in caecilians
CHORDATE EPIDERMIS DERMIS
5.REPTILES ‘thick stratum corneum
‘with epidermal scales molts at regular internal
‘presence of unique horny surface features
‘integumentary glands are not abundant
‘scales,scutes,rattles,clansz,plaque,spiny crests
‘bony dermal,bones are more abundant
‘osteoderms
1.lizards-underlying the
epidermal scales
2.snakes-absent
Reptilian
CHORDATE EPIDERMIS DERMIS
6.AVES ‘thin-skinned
‘epidermal scales umited to feet and base of breaks
‘presence of sharp clans
‘integumentary glands are absent
‘uropygial gland caudal, oil the feathers
‘with feathers
.down
.filoplumes
.rectrices
.remiges
‘dermis supports the feathers and arrectures pilorum/ plumarun
‘exceptionally thin
‘motility of skin is correlated to thermoregulatory function of feathers
‘no osteoderms
‘with spurs both sexes
.tarsometatasus
.carpometasus in some
CHORDATE EPIDERMIS DERMIS
7.MAMMALS ‘hairs are present arising from hair follicles
‘epidermal glands
.sebaceous-sebum
.sudoriferous-sweat
.mammary-milk
‘stratum germinativum is germinating
‘dense stratum corneum
‘derivatives
.claws
.horns
.hairs
.nails
.baleen whale bone
hangs or oral cavity
‘presence of hair follicle,arrector muscles,sweat,
sebaceous glands,conn. tissues
‘highly vascularized
‘with nerve endings
‘has thermoregulatory function-homiothermic
‘hypodermis or subcutaneous layer separates skin from muscles
‘with pigment cells
THE MAMMALIAN SKIN
Stratum corneum
Stratum granulosumStratum spinosum
Stratum basale (germinativum)
Stratum lucidum**
**Thick skin only
Stratum BasaleLowest epidermal layer, near dermisGood nutrient supplyReproduces by mitosisCuboidal, columnar in shapeMoves to upper epidermis in 27 days.
Stratum SpinosumLiving cellsDividing8-10 cells thickPolygonal in appearance
Stratus Granulosum, Lucidum Poor nutrient
supply.Flatten layer of
cells.3-5 cells thick.No cell division.Keratin
accumulates.
Found only in very thick skin.
Translucent.Highly keratinized.Dead cells
Stratum Corneum25-30 cells thick.Cells are filled with keratin and hardened.Sloughed off.Outer most layer of epidermis.Keratinocytes
MelanocyteProduces melanin
for protection from UV radiation.
Responsible for skin color.
Melanoma.
Melanocyte
Irregular Dense Connective TissueCollagenous fibers
Layers of the dermis1. Stratum papillarosum
- superficial region(1/5) of the dermis,consists of areolar connective tissues with elastic fibers- contains dermal papillae that house capillaries,touch corpuscles,& free nerve endings
2. Stratum reticularosum- the deeper portion (4/5 of the dermis)- with dense regular conn. Tissue with bundles of collagen and elastic fibers- spaces between fibers contain adipocytes,hair follicles,nerves,sebaceous glands, sudoriferous glands
Sweat glandSebaceous glandArrector pili muscleBlood vessels
FEATURE THIN SKIN THICK SKIN
1. Distribution All parts of the body except palms,palmar digits,soles
Palms,palmar surface of digits and soles
2. Epidermal thickness 0.10-0.15mm 0.6 – 4.5 mm
3. Epidermal Strata Lack stratum lucidum,thinner s. spinosum and s. corneum
Thick s. lucidum,spinosum,corneum
4. epidermal Ridges Lacking due to poorly developed or fewer dermal papillae
Present due to well- developed or numerous dermal papillae
5. Hair follicles and Arrector pili Muscle
Present Absent
6. Sebaceous Glands Present Absent
7. Sudoriferpous Gland Fewer More numerous
8. Sensory Receptors Sparser denser
DERIVATIVES OF THE EPIDERMIS1. HAIR
PARTS OF HAIRA. HAIR ROOT D. HAIR FOLLICLE
B. HAIR SHAFT E. HAIR CORTEX
C. HAIR BULB F. HAIR MEDULLA
Hair Follicle
TYPES OF HAIRA. ANGORAB. DEFINITIVE HAIRC. LANUGO
2. NAILA. NAIL ROOTB. NAIL BEDC. LUNULA
Angora Hair
Definitive Hair
Lanugo Hair
Sebaceous Gland
DERIVATIVES OF THE DERMIS
Sweat GlandSKIN GLANDS
Types of Sweat Glands(Sudoriferous Glands)Merocrine glands: release fluid by
exocytosisEccrine
Most commonSecretion is mostly water with solutesCools body down
ApocrineDevelops scent as bacteria metabolize
secretionStimulated when frightened, during pain,
during emotional upset
APOCRINE SWEAT GLAND
ECCRINE SWEAT GLAND
Sensory Structures of DermisDeep touch/pressure: Pacinian corpuscles
Light touch/pressure: Meisner’s corpuscles
Warm temperature: Free nerve endings
Cold temperature: Free nerve endings
Pain: Free nerve endings
Recognized by adipose tissue.
FACTORS INFLUENCING SKIN COLOR1. GENETIC INFORMATION2. AMOUNT OF MELANIN PIGMENTS3. DEGREE OF OXYGENATION4. HORMONES
* MSH5. EXPOSURE TO SUNLIGHT
WHITE SKIN
BROWN SKIN