Integument.pdf

integument and its derrivatives by asif ibrahim kanth

1. INTEGUMENT
STRUCTURE AND ITS DERIVATIVES
By
Prof. Sudesh Rathod
By
Mohd Asif Kan!
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2. Integument
?Integument is outer protective covering of a
vertebrate.
?The cutaneous membrane (skin) and its
derivatives (exoskeleton) are together referred
as integument.
?Performs
?Protection
?Respiration
?Temperature Control
?Nourishment of Young
?Locomotion and reproductive structures

3. Focus
Skin proper:
?Basic structure of skin
?Glands
Derivatives:
?The keratinized stratum corneumis involved
in development of various derivativeslike
scales hair, claws, teeth, nails, beaks, hooves,
horns, feathers etc.

4. Skin
?Epidermis
derived from epidermis made of
basically five layers and gives rise to
glands
?Stratum Corneum
?Stratum Lucidum(thick skin)
?Stratum Granulosum
?Stratum Spinosum
?Stratum Basale
?Dermis
derived fro and mesoderm divided
into uppermost very thin papillary
layer followed by stratum laxum
and deeper stratum compactum
(collagen fibres)

5. Skin Colour
?melanophores(black), iridophores(silvery), xanthophores
(yellow) and erythrophore(red)
?Melanocytes–manufacture melanin-in Stratum Spinosum
?Keratinocytes–most abundant, undergo keratinization
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6. Derivatives of skin
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7. Integumentary Glands:
?Epidermal glands are formed from the
Malpighianlayer of the epidermis
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8. Integumentary Glands:
Mode of secretion of glands
Merocrine
?Cellbodynotinjured
?Releaseparticlesbyexocytosis
?Mostsweatglandsandsalivaryglandsin
mammals
Holocrine
?Cellbodydischargedwithcontents
?Wholecelldies
?Sebaceousglands
Apocrine
?Cellularproductsgatheronsurfacethenpinched
off
?Apicalportionpinchedoff
?Axillarysweatglands,pheromoneglands
They are also referred as mucus, salivary, sweat, luminescent , poison,
sebaceous, uropygial, scent (musk and femoral), mammary glands on the basis
of secretion
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9. Glands: Structural classification
?Unicellular glands
?Tubular glands
?Alveolar, saccularor acinarglands
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10. Simple Glands
?Simple tubular: Simple tubular glands are present in
the intestine (e.g., Crypts of Leiberkuhn).
?Simple alveolar (acinar): Terminal part forms
alveolus e.g., Mucous glands in skin of frog, poison
glands in toad.
?Simple coiled tubular: Terminal part is coiled e.g.,
sweat gland.
?Simple Branched tubular: Gastric glands in
stomach.
?Simple Branched alveolar(acinar) e.g., Sebaceous
gland.

11. Compound Glands
?Compound tubular gland: Mammary glands
of monotremes.
?Compound saccular(acinar) gland: e.g.,
Salivary glands, (sub-maxillary and sub-
lingual).
?Compound tubulo-alveolar: They are tubular
as well as alveolar and are found in mammary
glands of higher mammals, pancreas, parotid
salivary gland, Cowper's glands and Bartholin
glands.

12. Types of glands on the basis of
functions
?Mucous glands: unicellular or multicellular.
They secret mucous that keeps skin moist and
slippery eg. Amphioxus, cyclostomes, fish,
amphibians
?Luminescent glands: Deep sea fishes have
along the sides of body

13. Amphibian Poison glands:
?Amphibians have multicellular alveolar
glands secreting poison (Parotid gland in
toads)
?Caecilians have giant poison glands
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14. Amniotes
?Male lizards have femoral glands below thighs in a row
from knee to cloaca. Secrete sticky substance which
hardens while copulation.
?Uropygialglands are present in birds on dorsal side of tail
secrete oil in aquatic birds more effectively.
?Sweat glands in mammals are distributed variously on their
body. E.g. cats, rats and mice confined to soles; bats on
sides of head; rabbits around lips, ruminants muzzle and
between digits etc. except in Tachyglossus, sireniaand
Cetaceans

15. ?Sebaceous glands: Alveolar glands in hair
follicle;
?Meibomianare modified sebaceous glands on
eyelids
?Scent glands: allure the opposite sex; modified
sweat or sebaceous glands.
?Mammary glands: Monotremeshave no nipple.

16. SCALES

17. ?In Ostracodermsthere
were armourof large
bony plates, which
reduced in size in
Placodermsto form
cosmoidscales.
Ganoidscales were
found in other types of
primitive fish.
Presently these are
seen in Polypterus
with reduced cosmine
layer.
?Ganoidscales with
subsequent loss of
ganoidlayer gave rise
to Leptoidscale as
cycloid and ctenoid.

18. Scales:Dermal and Epidermal
Dermal Scales:
?Dermal bone plates
became skull
?Ancient armor
?Rhomboid scales
?Modern fish
?Cycloid and ctenoidscales
?Placoidand ganoidscales
Cycloid, ctenoid, placoid, and ganoidscales of
modern fish

19. CosmoidScales in Fish
?Cosmoidscales
?Modified dentin layer called Cosmine
?Extinct sarcopterygians
?Ganoidscales
?Modified thick enamel layer called ganoine
?Found in gars

20. Dermal scales in
Elasmobranches
aPlacoidscales have evolved
by loss of some layers of
cosmoid scale.
aConsists of basal plate and
spine, and originates from
dermal layer.
aA group of odontoblasts
collect in the dermis to form
dermal papilla.
aDermal papilla grows
upwards pushing in
epidermis. Odontoblats
secrete dentineto form basal
plate and spine as it grows.
The malpighian layer in contact to dermal papilla is called enamel
organ secretes vitrodentineor enamel.
Overlying epidermis wears off and scale’s spine is exposed
The odontoblaststurn into pulp cavity connective tissue

21. Amphibians
?Loses dermal scales
?Exception: caecilian
?Epidermal multicellular glands abundant
?Stratum corneum cornified (warts of toads)

22. Epidermal scales
?Thick stratum corneumwith modifications
?Epidermalscales
?Some reptiles have remnants of dermal armor
(osteoderms)
?Osteodermsbeneath some epidermal scales
?Gastralia-large osteoderms
?Alligator and skinks
?True dermal bones
?Turtles
?Epidermis also develops teeth in Cyclostomes
(lamprey and hagfish).

23. Reptilians
?Epidermal scales first
appear in reptiles.
?cornified epidermis result
in the formation of horny
scales or scutes.
?They undergo ecdysis
periodically.
?many lizards have
osteoderms(developed
from dermis) underlying
the epidermal scale.
Osteoderms(dermal plates or scutes) of alligator.

24. Corneal structures
?Tail of rattle snake scales are modified to
form a rattle. It consists of series of old dried
scales.

25. Birds and Mammals
?Epidermal scales in birds and mammals have
been disappeared.
?they persist on legs of birds on legs and tails of
variety of mammals(rodents). Palm of primates.
?Pangolinhas redeveloped large horny scales.

26. Feather

27. Feather
?Feather are
characteristics of
birds only.
?Develop from
highly specialized
cornified
epidermis.
?some fossilized
reptiles were
having feathers.

28. ?Modification of reptilian
scales
?3 types
?Contour-flight feather
?provides wing shape
?Down-beneath contour
feather (insulation)
?Filoplume-long shaft lost its
vane
Feather moultingoccurs every
annually or biannually
Feathers provide wide range of
coloration to birds

29. Stages of contour feather
Quill lies in a follicle, a cylindrical
pit extending down into dermis but
surrounded by epidermal sheath.
Exposed and expanded portion
Vane and axis shaft or rachis

30. ?Detailed structure of a feather

31. Hair

32. Hair
?Modifications of stratum corneum
(epidermal)
?Like filoplume feather and
lack details.
?Vibrissae
?Specialized hairs
?Tactile in function

33. Whalebone
aBaleen Plate
?Toothless whale’s horny sheets of oral
ectoderm having hair.
?Not bone
?Used for filter feeding

34. Hair development

35. Antlers, Horns and
Digital Tips

36. Antler
?Antlers and horns of
giraffe
?Only in male Deer (stag)
?Mesodermal in origin
?Dermal bone of antler
attaches to skull bone
?Shed annually
?Outside layer is highly
vascularized(velvet)
Fig. :-Idealized growing antler. V velvet, E epidermis, D dermis, VC vascular channels, P
periosteum, R reserve mesenchyme, PC prechondroblasticzone, CB chondroblastic
zone, C chondrocyticzone, M mineralized cartilage, S sleeve bone, 1 primary spongiosa,
2 secondary spongiosa, PD pedicle, F frontal bone

37. ?Development of an antler

38. Horns
?Horns
?In Bovine family
?Outgrowth of dermal
core
?Unbranched
?Covered by epidermal
horny, keratinized
sheath
?Permanent

39. Digital Tips
?Nail: are found in primates
?Dorsal unguis is large and subunguisis
reduced.

40. Claws
?Claws first appear in reptiles
?Claws of birds and reptiles are similar but in
mammals subunguisis much reduced.
?In cat family the claws are retractile.
?Subunguisin mammals continue with digit pad.
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41. Hoof
?Hooves are found in ungulates. sheep, cows, horses
etc.
?The unguis is thick and curved and encloses the
subunguis
?Behind the hoof is a pad.
?The hoof is a cylinder of horny material that
surrounds and protects the tip of the toe

42. [email protected]

43. Thank you
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MOHD ASIF KANTH
CONTACT
M.Sc,M-Phil,B.ed,D-pharma
9070262786
9018533143
aasifi[email protected]