Integument System

Integument system

One of the largest systems.Includes-hair, hooves, horns, claws, and

glandsContiguous with mucous membranesOuter surface is dead!!

KeratinizationThickness depends on species/location

Functions

Prevent desiccationReduces injuryMaintain body temperatureExcrete water and wastesSensorySynthesis of Vitamin D

Layers

Epidermis Keratinized stratified squamous epithelium Basement membrane

Dermal papillae-interdigitations epidermis and dermis

Layers

DermisDense fibro elastic connective tissue “Hide” of the animalMeissner’s corpuscles-light touch

receptorsTension lines

Layers

Subcutaneous layer

(hypodermis)Adipose tissue Insulation, shock absorberPacinian corpuscle-deep touch

So where do we give shots??

Injections

It depends! Intradermal injections

Allergy testingHuman rabies vaccine

Subq injectionsMost vaccines

Epidermal cells

Keratinocyte-Cells have lost nucleus, cytosol, and

organelles. New epidermis q7-8 months in humans!

MelanocytesDeep epidermal layersProduces melanin, stored in cellsReleased and absorbed into keratinocytes

Protection from UV

Epidermal cells

Langerhans’ cellMacrophage systemProduced in bone marrow, then migrate to

skinPhagocytosis of invadersStimulate immune response

Merkel cells + sensory nerve endingsAid in sensation

Special features-pigmentation

Presence of melanocytes Melanocyte-stimulating

hormone Granules to arms then

released to keratocytes Darker pigmentation Released by hypophysis Blocks from UV rays

Special features-paw pads

Toughest, thickest skin on animals body Fat and CT foundation, with sweat glands Protect against abrasions and thermal

variations (walking on hot or cold) Conical papillae cover

Carpal pad Metacarpal/metatarsal pad Digital pads

Special features-Planum nasale

Top of the noseMuzzle (planum nasolabiale)-horse and

cowNot an indicator of health status!!!!!!!!Histologically-thinner than expectedNo glands-wet from licking-DogsSheep, pigs and cows-glands

Special features-Ergots and Chestnuts

Thick, horny structuresEquine familyRemnent of carpal and tarsal

pads

Hair=fur

InsulationMaintaining body temperature

CamouflageThickest on most exposed surfaces

DorsumLateral

Hair

Hair FollicleEpidermis

invaginatesHair bulb-

Deepest portionPapilla-base of bulbMatrix-covers papilla-

rapidly growing epithelial cells

Hair

Shaft-exposed portion

Older cells pushed further from papilla

Become keratinized and die

Hair

Layers of the hair Medulla-central core

Soft keratin Flexible

Cortex Hard keratin Thickest layer

Cuticle Single outer layer-”shingles” Hard keratin Wool-raised cell

Growth cycle-hair

Anagen-growth phaseReaches maximum length (genetically

determined)Telogen-resting phase

Follicle shortensWeeks to yearsTelogen effuvium=blowing the coat

Catagen-transition phase

Hair color

Pigment in cortex and medullaMelanin-melanocytes at base of follicleDogs have two types of melaninHorses only oneGrey-melanin production decreasesWhite hair-medulla of hair filled with air,

complete loss of pigment

Types of Hair

Types of hairTactile elevation-raised surface of epidermis

Tylotrich hairs=tactile hairsRoot hair plexus-touch receptorsSinus hair-blood sinus

Primary hairs-”guard hairs”Secondary hairs-”undercoat”

Up to 15 hairs per epidermal orifice or pore

Implantation angle Summer vs. winter coat in horses

Arrector pili muscleSympathetic nervous system “goose bumps”

Glands of the Skin

Sebaceous glandsSweat glandsTail glandsAnal Sacs

Glands of the Skin-sebaceous glands

Sebaceous glands Hair follicle Mucocutaneous junctions Ear canals Releases sebum or lanolin (sheep) Released with arrector pili mm,

hormonal control Antibacterial properties White heads blackheads

(comedones) pimple/pustules

Glands of the Skin-sweat glands

Cover entire body-in all domestic animals

Watery, transparent-evaporative coolingMerocrine glands-no loss of cell to

excrete

Glands of the Skin-tail gland

Dogs and CatsDorsal base of the tailRecognition/identificationSensitive to sex hormones

Glands of the Skin-Anal Glands

Scent glandsNormally expressed with normal BM

The Hoof

Ungulates=hoofed animalsOuter covering-hoof or clawCorium-attached to bone

Hoof and corium interdigitateRich blood supplyWell innervatedGrowth of hoof – coronary coriumHorseshoe helps strengthen hoof

Laminae Interdigitation of

corium and hoof wall

Laminitis Inflammation of

lamina

Hoof anatomy

The Wall Heel Quarter Toe

Sole Palmar/plantar view

White line Jct. of sole and hoof wall

Frog

Horns vs. Antlers

Horn process-frontal boneCovered by coriumEpidermis in originContinuous growing (except

pronghorns!)Dehorning-cauterize the coriumPolled breeds-bred to be horn free

Antlers

Grow and shed annuallyGenerally, maleDermal in origin –bone developmentBlood supply-externally (velvet)Once completely grown-CT band

constricts blood supply to velvet.

Comparative Anatomy

Avian-Integument

Keratin-needed to produce scales, feathers and beaks and claws. Dermis very thin-slow to heal. Best sites of subQ-wing folds and dorsal trunk and neck

“Fluffed birds”-erector muscle of the dermis raise feathers to trap body heat Fluffed and at the bottom of the cage-Not GOOD!!

Glands-no sweat glands Uropygial or preen gland

Dorsal aspect of tail Helps clean and waterproof feathers

Avian-Integument

Beak/Bill-upper and lower mandible; equivalent of mammalian lipsTearing foodCapture foodPreeningPicking up material-nesting

Claws-specialized scalesBeaks and Claws grow continually

Avian Integument

Combs, Wattles and SnoodSpecialized adaptationCan be trimmed off to prevent damage in

commercial operationsChickens below showing signs of Avian

Influenza

Normal Comb-right

Swollen Wattles

Snood

Avian Integument

Cere=fleshy membrane at the base of the beak, location of nares Budgerigars-helps sex mature budgies??

Other Options of Sexing Birds DNA testing Visualization of gonads

Blue-male Brown-female

Male or Female??

Avian-Integument

FeathersFunctions: flight, protection,

thermoregulation, camouflage, behaviors (courtship, defense, recognition)

Avian- Integument

Feather Anatomy Inferior Umbilicus-vesselsSuperior Umbilicus- small

hole-start of the webbed portion

Calamus-quill; between IU and SU

Rachis-main feather shaftVane-weblike, flattened part

of feather

Avian Integument

Vane is made up of barbs, barbules and hooklets (interlock)

Looser feather weaveFeels softerAllows air to pass through-

creating silent flight

Avian Integument

Types of FeathersContour-main feather that covers the birds

body; flight feathers, tail feathers

Avian Integument

Types of FeathersSemiplume- located under contour feathers,

on sides of the abdomen, along neck and back

Lack barbules and hooklets Insulation and Buoyancy

Down-lack a true shaft,

barbules and hooklets Insulation

Semiplume

Down

Avian Integument

Types of feathersFiloplume- bare shaft with no barbs except

at the tipDorsal back/neckSensory role –pressure and vibration sense

Bristle-Sense of touchAround eyes, nostrils, mouth, and toes

Avian Integument

Feather typesPowder Down Feather

Continually growingProduce a waxy powder for

cleaning and waterproofing feathers.

Birds without preen gland - Herons

Avian Integument

Feather DamageChewing, mitesStress bars-stress during growth phase of

feather; weakened vane and barbs lack barbules—Nutritional stress

Avian Integument

Molting=the process of feather replacementSpecies variation Influenced by season, temperature,

nutrition, egg laying, species and sexGenerally symmetrical and gradual

replacement of flight feathersWaterfowl-molt all their flight feathers at

once right after breeding season-Postnuptial

Avian Integument

MoltingRequires good quality nutrition4-12% body weight is feathers!Germinal cells in dermal papilla activated

by: Increasing day length

Stimulates pituitary and thyroid gland to produce hormone

Sex hormones also play a role

Blood feather=growing feather

Feather Development

Avian-wing trim

Blood feathers?“They still fly”

We aren’t preventing flight, but preventing them from reaching great heights!

Glide quite well!!

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