Integument System
Integument system
One of the largest systems.
 Includes-hair, hooves, horns, claws, and
glands
 Contiguous with mucous membranes
 Outer surface is dead!!
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Keratinization
Thickness depends on species/location
Functions
Prevent desiccation
 Reduces injury
 Maintain body temperature
 Excrete water and wastes
 Sensory
 Synthesis of Vitamin D
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Layers

Epidermis
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Keratinized stratified squamous epithelium
Basement membrane
 Dermal papillae-interdigitations epidermis and
dermis
Layers
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Dermis
Dense fibro elastic connective tissue
 “Hide” of the animal
 Meissner’s corpuscles-light touch
receptors
 Tension lines
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Layers
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Subcutaneous layer
(hypodermis)
Adipose tissue
 Insulation, shock absorber
 Pacinian corpuscle-deep touch
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So where do we give shots??
Injections
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It depends!
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Intradermal injections
Allergy testing
 Human rabies vaccine
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Subq injections
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Most vaccines
Epidermal cells

KeratinocyteCells have lost nucleus, cytosol, and
organelles.
 New epidermis q7-8 months in humans!
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Melanocytes
Deep epidermal layers
 Produces melanin, stored in cells
 Released and absorbed into keratinocytes
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Protection from UV
Epidermal cells

Langerhans’ cell
Macrophage system
 Produced in bone marrow, then migrate to
skin
 Phagocytosis of invaders
 Stimulate immune response
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Merkel cells + sensory nerve endings

Aid in sensation
Special features-pigmentation

Presence of melanocytes
 Melanocyte-stimulating
hormone
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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
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Carpal pad
Metacarpal/metatarsal pad
Digital pads
Special features-Planum nasale
Top of the nose
 Muzzle (planum nasolabiale)-horse and
cow
 Not an indicator of health status!!!!!!!!
 Histologically-thinner than expected
 No glands-wet from licking-Dogs
 Sheep, pigs and cows-glands

Special features-Ergots and
Chestnuts
Thick, horny structures
 Equine family
 Remnent of carpal and tarsal
pads
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Hair=fur
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Insulation

Maintaining body temperature
Camouflage
 Thickest on most exposed surfaces
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Dorsum
 Lateral
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Hair
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Hair Follicle
Epidermis
invaginates
 Hair bulb
Deepest portion
 Papilla-base of bulb
 Matrix-covers papillarapidly growing
epithelial cells

Hair
Shaft-exposed
portion
 Older cells
pushed further
from papilla
 Become
keratinized
and die
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Hair
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Layers of the hair
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Medulla-central core
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Cortex
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Soft keratin
Flexible
Hard keratin
Thickest layer
Cuticle
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Single outer layer-”shingles”
Hard keratin
Wool-raised cell
Growth cycle-hair

Anagen-growth phase
Reaches maximum length (genetically
determined)
 Telogen-resting phase

Follicle shortens
 Weeks to years
 Telogen effuvium=blowing the coat
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Catagen-transition phase
Hair color
Pigment in cortex and medulla
 Melanin-melanocytes at base of follicle
 Dogs have two types of melanin
 Horses only one
 Grey-melanin production decreases
 White hair-medulla of hair filled with air,
complete loss of pigment
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Types of Hair
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Types of hair
Tactile elevation-raised
surface of epidermis
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Tylotrich hairs=tactile hairs
 Root hair plexus-touch receptors
 Sinus hair-blood sinus
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Primary hairs-”guard hairs”
 Secondary hairs-”undercoat”

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Up to 15 hairs per epidermal orifice or
pore

Implantation angle
Summer vs. winter coat in horses

Arrector pili muscle
Sympathetic nervous system
 “goose bumps”
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Glands of the Skin
Sebaceous glands
 Sweat glands
 Tail glands
 Anal Sacs
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Glands of the Skin-sebaceous
glands
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Sebaceous glands
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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 cooling
 Merocrine glands-no loss of cell to
excrete

Glands of the Skin-tail gland
Dogs and Cats
 Dorsal base of the tail
 Recognition/identification
 Sensitive to sex hormones
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Glands of the Skin-Anal Glands
Scent glands
 Normally expressed with normal BM
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The Hoof
Ungulates=hoofed animals
 Outer covering-hoof or claw
 Corium-attached to bone
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Hoof and corium interdigitate
Rich blood supply
 Well innervated
 Growth of hoof – coronary corium
 Horseshoe helps strengthen hoof
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Laminae
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Interdigitation of
corium and hoof
wall
Laminitis

Inflammation of
lamina
Hoof anatomy
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The Wall
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Sole
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Palmar/plantar view
White line
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Heel
Quarter
Toe
Jct. of sole and hoof wall
Frog
Horns vs. Antlers
Horn process-frontal bone
 Covered by corium
 Epidermis in origin
 Continuous growing (except
pronghorns!)
 Dehorning-cauterize the corium
 Polled breeds-bred to be horn free

Antlers
Grow and shed annually
 Generally, male
 Dermal in origin –bone development
 Blood supply-externally (velvet)
 Once completely grown-CT band
constricts blood supply to velvet.
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Comparative
Anatomy
Avian-Integument
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Keratin-needed to produce scales, feathers and beaks
and claws.
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“Fluffed birds”-erector muscle of the dermis raise
feathers to trap body heat
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Dermis very thin-slow to heal.
Best sites of subQ-wing folds and dorsal trunk and neck
Fluffed and at the bottom of the cage-Not GOOD!!
Glands-no sweat glands
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Uropygial or preen gland
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Dorsal aspect of tail
Helps clean and waterproof feathers
Avian-Integument
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Beak/Bill-upper and lower mandible;
equivalent of mammalian lips
Tearing food
 Capture food
 Preening
 Picking up material-nesting
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Claws-specialized scales
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Beaks and Claws grow continually
Avian Integument
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Combs, Wattles and Snood
Specialized adaptation
 Can be trimmed off to prevent damage in
commercial operations
 Chickens below showing signs of Avian
Influenza
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Normal Comb-right
Snood
Avian Integument
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Cere=fleshy membrane at the base of the
beak, location of nares
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Budgerigars-helps sex mature budgies??
Blue-male
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Other Options of Sexing Birds
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DNA testing
Visualization of gonads
Brown-female
Male or Female??
Avian-Integument
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Feathers
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Functions: flight, protection,
thermoregulation, camouflage, behaviors
(courtship, defense, recognition)
Avian- Integument
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Feather Anatomy
Inferior Umbilicus-vessels
 Superior Umbilicus- small
hole-start of the webbed
portion
 Calamus-quill; between IU
and SU
 Rachis-main feather shaft
 Vane-weblike, flattened part
of feather

Avian Integument
Vane is made up of barbs,
barbules and hooklets
(interlock)
 Looser feather weave

Feels softer
 Allows air to pass throughcreating silent flight
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Avian Integument
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Types of Feathers
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Contour-main feather that covers the birds
body; flight feathers, tail feathers
Avian Integument
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Types of Feathers
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Semiplume- located under contour feathers,
on sides of the abdomen, along neck and
back
Lack barbules and hooklets
 Insulation and Buoyancy
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Down-lack a true shaft,
barbules and hooklets
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Semiplume
Insulation
Down
Avian Integument
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Types of feathers
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Filoplume- bare shaft with no barbs except
at the tip
Dorsal back/neck
 Sensory role –pressure and vibration sense
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BristleSense of touch
 Around eyes, nostrils, mouth, and toes
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Avian Integument
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Feather types
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Powder Down Feather
Continually growing
 Produce a waxy powder for
cleaning and waterproofing
feathers.
 Birds without preen gland Herons
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Avian Integument

Feather Damage
Chewing, mites
 Stress bars-stress during growth phase of
feather; weakened vane and barbs lack
barbules—Nutritional stress
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Avian Integument
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Molting=the process of feather
replacement
Species variation
 Influenced by season, temperature,
nutrition, egg laying, species and sex
 Generally symmetrical and gradual
replacement of flight feathers
 Waterfowl-molt all their flight feathers at
once right after breeding season-Postnuptial
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Avian Integument
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Molting
Requires good quality nutrition
 4-12% body weight is feathers!
 Germinal cells in dermal papilla activated
by:
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Increasing day length
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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”
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We aren’t
preventing flight,
but preventing them
from reaching great
heights!
 Glide quite well!!
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