ENI - Exotic Integument Flashcards
What information can be gained from the condition of skin and feathers of birds?
- General health
- Nutrition status
- Management
- Environemental conditions
What is pododermatitis in birds?
- Bumblefoot
- Occurs in captivity due to inappropriately sized perches, obesity, hard perches, concrete lined ponds and walking on gravel
- Will see loss of pimples initially, then swellign and ulceration
- Advanced stages will see ulceration, inflammation, necrotic plugs of tissue, deep tissue and bone damage
Give some differences between the integumet of brids and mammals
- Avian thinner dermis
- Lack of hair follicles, have feather follicles
- Virtually glandless skin
- Skin of legs and feet in birds are different = podotheca
What are the layers of the epidermis in birds?
- Basal/germinative layer
- Intermediate layer
- Outer cornified layer
What is the function of the straited muscles found in the epidermis of birds?
To move skin
What are the division of the dermis in birds?
- Superficial layer
- Deep layer
Describe the superficial dermal layer of birds
- Varies in thickness depending on position and age
- Loosely arranged layers of collagen in interwoven bundles
Describe the deep dermal layer of birds
- Fat
- Feather follicles
- Smooth muscles that control movement of feathers
- Blood vessels and nerves that supply the dermis and epidermis
Describe the subcutaneous layer of bird skin
- Loose connective tissue
- Fat layer and discrete fat bodies
- Fat bodies yellow deposits beneath skin
- Areas of fat deposition vary from species to species and time of year (high in aquatic birds, pre-migration depositoin)
Why are the fat bodies of the subcutaneous layer of avian skin yellow?
Carotenoid pigments deposited into fat
What are some common areas of fat deposition in birds?
- Lateral pectoral muscles
- Cloacal region
- Back
Describe the podotheca
- Skin of feet and legs in birds
- Non-feathered
- Scales formed from raised heavily keratinised epidermis separated by folds of less keratinised tissue
- Pimpled architecture or smooth/wrinkled
Describe the attachment of the skin to the underlying muscles in the bird
- Over head, extremities adn sternum firly attached, non-moveable
- Over remainder of body more loosely attached but still limited moveability
Describe the glandular tissue of avian integument
- Effectively glandless
- lacking sebaceous and sweat glands
- Do have some specialised glands
List the glands of the avian skin
- Uropygial gland (preen gland)
- Glands of ear canal
- Pericloacal glands
Describe the uropygial gland
- Aka preen gland
- Holocrine
- Bilobed
- Dorsal to cloaca at end of pygostyle
- Caudally directed nipple
- Not present in all species (if not, need keratinocytes)
What is the function of the uropygial gland?
- Maintaining feather confition and secretions spread by preening
- Waterproofing (by keeping feathers in good repair)
- Contains pro-vitamin D, converted by UV to active vit D
- Suppress growth of micro-organisms
Describe the keratinocytes in birds
- Developing dermal cells undergo metamorphosis from cuboidal to squamous nature
- Lose organelles
- produce lipids and fibrous proteins (keratin)
- Dehydrate and lyse
- Lipid production from these makes entire skin “oil producing” gland
What are patagia in birds?
Skin reflected into flat, membrane like structures in areas where wings, legs, neck and tail join the body
Name and give the location of the 4 wing patagia
- Propatagium: neck and wing
- Postpatagium: caudal angle of carpi
- Metapatagium: caudal junction of wing and thorax
- Alular patagium: interspace btween alula and carpi
What is the function of the wing patagia?
Stability and aerodynamics
Describe the structure of the avian beak
- Bones of maxilla and mandible with horny covering (rhamphotheca)
- Similar to skin with modified epidermis
- Stratum corneum thick, cell bound calcium phosphate and layered crystals of hydroxyapatite, abundant keratin
- Combine to give beak hardness
Describe the bill tip organ in birds
- Mechanoreceptors in distal tip of beak
- Papillae from dermis ending in crater-like structures
- Sensitive to heat, cold, pressure and pain
- Variably present depending on feeding method (not in pecking)
Describe the cere of birds
- Situated at base of upper beak
- Composed of keratinised skin
- Nostrils
- Colour influenced by diet and hormones male budgies blue due to testosterone)
List the functions of feathers
- Flight
- Insulation
- Waterproofing
- Courtship, defence, aggressive territoral behaviour
What are pterylae and apteria?
- Pterylae: areas that contain feather tracts
- Apteria: areas without feather tracts
What are the components of feathers?
- Calamus
- Rachis
- Shaft
- Vane or vexillum
Describe the calamus of the feather
- Shot, hollow, tubular unpigmented end of mature feather
- Inserted into follicle
- Present below skin
- Normal appearance is rounded, may appear pinched off if disease
Describe the rachis of the feather
- Long, solid tubular extension of calamus above skin
- Contains pith composed of air-filled keratinised epithelial cells surrounded by soild keratinised outer cortex
Describe the shaft of the feather
Made up of calamus and rachis
Describe the vane or vexillum of the feather
- Portion of feather either side of rachis
- Composed of barbs and associated structures
- Vane either plumulaceous or pennaceous depending on individual feather type
How is the type of feather characterised?
Structure of rachis, barbs and barbules
- 10 types recognised
Describe the
a. countour feathers
b. covert feathers
c. remiges
d. retrices
a. predominant feather covering body
b. small countour feathers of wing and tail
c. large stiff feathers of wing
d. large flight feathers of tail
Names some specialised adapted feathers
- Semiplumes
- Hypopnea
- Filiplumes
- Bristles
Describe the down feathers
- Adult and natal
- Powder down feathers disintegrate and produce keratin powder that is spread thorugh feathers uring preening
- May be lacking in disease
Outline feather growth
- Feathers from feather follicles
- Invaginations of skin and closely fit calamus
- Follicle consists of epidermal and dermal eclls
- At umbilicus of calamus, dermis carries hump of pulp into tip of calamus
- Follicle lined by epidermal cells both living and cornified
Describe the innervation of the feather structures
- Follicular wall abundant sensory supply
- Papillae, pulp and feather muscles also well innervated
Describe the function of the smooth muscles at the base of feather follicles
- Maintain body temperature
- Increase or decrease elevation of feathers from skin
What is the function of Herbst’s corpuscles and where are they located?
- Base of feather follicles
- Detect subtle ground vibrations and changes in air current
Describe the process of moulting in birds
- Soft keratin structures (scales, comb, wattle, cere) underogo constant moult and replacement similar way to mammalian skin
- Feathers moult by growth of new feather, shedding of old one
What are the different moult patterns seen in birds?
- Gradual: last many months
- Dramatic: over in a few weeks
- Continual: powder down feathers
Describe the proximal control of feather moulting
- Complex, influenced by circannual rhyhms of changing photoperiod and temperature
- Pineal-hypothalamic-pituitary and ANS-endocrine pathways
- Influenced by oestrogens, progestergens, thyroid hormones, catecholamines and prolactin
Describe the role of nutrition in moulting
- High metabolic and nutritional demand for feather growth
- Protein mainly in form of keratins, 90% of dry matter content of feathers
- Moult will proceed regardless of nutritional status of birds, leading to protracted moult, poor quality feathers
What are fret marks and how are they caused?
- Clear breakds in feather colour as a result of interruption in feather growth and malformation of featehr barbs
- Nutritional, environmental, disease, drug stresses
What factors determine feather colour?
- Biochromes
- Structural properties
Describe the role of biochromes in feather colour
- Colour pigments deposited at time of feather development
- Either natural: Intensity determined by availability of “free carotenoids in diet
- Or synthetic
Explain the role of structural properties in feather colour
- Inherent in development of feather
- Or induced by materials placed on feather after development that alter absorption and reflection of light
- Barbs and barbules scatter and reflect varying wavelengths = iridescent glow of feathers
- Green usually due to structural characteristics (giving blue colour) and yellow (pigments) overlapping
What, other than biochromes and structural properties, may affect feather colour?
- Disease e.g. Avian circovirus
- Malnutrition (esp. deficiencies in essential amino acids and vitamins)
- Red colouration of appendages due to vascularisation (e.g. wattles, combs)
Describe the condition “scaly face” in birds
- Knemidocoptics mites
- Hyperkeratosis of cere, beak and surrounding tissue leading to honeycombing of tissue
Describe the anatomy and physiology of ferret skin
- Fur: soft short undercoat, long coarse guard hairs
- Skin thick, numerous sebaceous glands
- No skin sweat glands
- Seasonal moults - thinner and lighter in spring, thicker and darker in autumn
Describe the hair of rabbits
- Long and short guard hairs and undercoat
- Natural colour is agouti
- Moult in spring and autumn
- Thick fur on feet instead of foot pads
- Vibrissae around face for sensing
Describe the skin of rabbits
- Submental, anal and inguinal scent glands
- No foot pads
What is the role of rabbits’ large ears?
Thermoregulation
Describe the hair of guinea pigs
- Vibrissae
- Agouti natural colour
- Long and short haired varietyes
- Also naked
Describe the skin of guinea pigs
- Thick foot pads
- Sebaceous glands approx 1 cm dorsal to anus
Describe the integument of chinchillas
- Dense soft coat, 60 hairs/follicle
- Fur slip
- Large, bald ears
- Footpads
- Small weak claws
- Vibrissae
Describe the integument of hamsters
- Vibrissae
- Skin loose and stretchy
- Large flank scent glands in syrian
- +/- ventral scent glands
Describe the integument of rats
- Guard hairs and undercoat
- Feet hairless, thick pads
- Naked rats
- Sweat glands only on feet
- Zymbal’s gland at base of ear
- Tail hairless, thermoregulation
- Vibrissae
Describe the integument of gerbils
- Guard hairs and undercoat
- Tail slip possible
- Ventral scent glands
Describe the integument of sugar gliders
- Females have pouch with 4 teats
- Cloaca
- Patagium between front and hign legs
- Scent gland on forehead and throat in males
- Both have paracloacal scent glands
- Tail slip possible
Describe the integument of african pygmy heedgehogs
- Spines are modified hairs
- Hair and sebaceous glands absent in spiny skin
- Sweat and sebaceous glands in haired skin and feet
Describe reptilian skin
- Dry with few glands
- Glandular tissue confined to femoral and pre-cloacal pores in some lizards
- 3 layers of epidermis
What are the functions of reptilian skin?
- Display
- Protection
- Camouflage
- Thermoregulation
- Fluid homeostasis
Describe the pre-cloacal and femoral pores in lizards
Males often have more pores and more prominent pores than female of same age and size
What are the 3 layers of reptilian epidermis?
- Stratum germinatum
- Intermediate layer
- Stratum corneum
What is the function of the stratum germinatum in reptiles?
- Divides
- Produces keratin
What is the function of the intermediate layer of reptilian epidermis?
Contains lipids
What is the function of the stratum corneum in the reptilian epidermis?
Forms scales and scutes
What are the 2 forms of keratin in reptilian skin?
- Alpha keratin
- Beta-keratin
Describe alpha-keratin in reptilian skin
- Flexible
- Found between scales and scutes and in hinges
Describe beta-keratin in reptilian skin
- Unique to reptiles
- hard
- Forms scutes, horns adn scales
Describe the hinges in reptilian skin
- Location varies
- Betwen scales of snake or lizard
- Bell’s Hingeback tortoise has hinge at back near legs, can close shell over legs
- Eastern box turtle can draw limbs and head into shell then close shell completely
Describe the dermis of reptiles
- Contains pigment cells, nerves and vessels
- Contains bony plates in some species e.g. crocodile, tortoise skink
Describe how the chelonian shell is formed
- 60 osteoderms
- Fused with ribs and parts of spine
- Covered by spidermal scutes or leathery skin
What are scutes?
Keratin overlying osteoderm
Describe the chromatophores in reptilian skin
- Lie between dermis and epidermis
- Influenced by autonomic nervous system, hormones, light and temperature
- Used in camouflage, display and thermoregulation
What colour are the melanophores?
Black, yellow and grey
What colour are carotenoid cells?
Yellow, red, orange
Describe iridophores
- Guanophores
- Lie in dermis
- Contain cyrstalline product guanine, reflects light
- Blue waves reflected more = blue colour
- Combine with carotenoids to give green colour
What are the functions of amphibian skin?
- Protection
- Sensory
- Thermoregulatory
- Fluid balance
Describe the skin layers in amphibians
- Epidermis thinner, easily damaged
- Dermis: outer stratum spongiosum and inner stratum compactum
- Dermis contains nerves, vessels, smooth muscle, chromatophores and specialised glands
Compare the stratum compactum in salamanders and anurans
- Salamanders: tightly adhered to underlying connective tissue
- Anurans: loosely attached to underlying connective tissue
Describe the functions of epidermal glands in amphibians
- Produce mucus or waxy substances (may enhance cutaneous respiration, or reduce evaporative water loss)
- Also toxins and other chemicals for pretection against predators and infection
Give some examples of toxins secreted by amphibians
- Poison arrow frogs
- Fire salamanders spray toxin from dorsal glands
- cane toads: parotid glands which release skin toxins
Describe the pelvic patch in anurans
- Area of increased vascularity on ventral pelvis
- Aka drinking patch
- Enables water absorption as most amphibians do not drink
What are the implications of skin permeability
- Administration of topical medications
- Soaking in shallow water aids rehydration
- Trace of environmetnal toxins and pollutants can cause illness and/or death
Describe the parietal eye in reptiles
- Found in many lizards
- Direct connection to pineal gland
- Regulation of body temperature
Describe the spectacles found in reptiles
- Clear scales over eyes of snakes and some geckos
- Fusion of upper and lower eyelids
- Continuous with skin
- Fluid between scale and eye
Describe the heat-sensory pits found in snakes
- Found in boas, pythons and vipers
- Pick up heat change of 0.1 degree
Describe some adaptations of reptiles used for display and/or defence
- Crests, frills, horns, gular pouches, spines
- Usually large in maes
Describe the cloacal spurs
- Retained pelvic vestiges in boids
- Courtship
- More pronounced in males
Describe the gastropeges in snakes
- Single row of large ventral scales
- Esed in locomotion
- Dig into surface to drag snake along
Describe the adhesive toe pads found in some lizards
- Geckoes
- Enable gripping of surfaces including glass
- Tiny rows of overlapping scales called lamella
- Each lamella in turn covered in tiny branching hairs called setae
What is ecdysis?
- Sehdding of skin under influence of thyroid gland
Compare ecdysis across reptilian species
- Snakes and geckos: shed whole skin, eaten by geckos
- Other lizards shed piecemeal
- Terrestrial tortoises shed legs, tail and neck only
- Aquatic cheloonia shed individual scutes
Describe the process of ecdysis
- Cells of intermediate layer replicate to form new 3 layer epidermis
- Lymph and enzymes diffuse between old and new, form cleavage zone
- Old skin shed
- New skin hardens
- Require humidity and rough surfaces
What are some of the implications of ecdysis?
- Skin more permeable, more vulnerable to parasites and infection
- Absorption of topical medications may be enhanced (toxicity)
- Snakes more skittish and aggressive
Describe the anatomy of the chelonian shell
- Dome shpaed carapace dorsally
- Flattened plastron ventrally
- Connected by bone struts
- Pelvic girdle some attachment to plastron
- 60 osteoderms, fused with ribs and parts of spine, covered by epidemal scutes or leathery skin
How do scutes of chelonians grow?
Addition of new keratin layers to base of each scute, can see these areas of growth and reflect history (nutrition, husbandry, previous trauma to shell etc)
What is a risk when handling hamsters?
- Traumatic exopthalmos
- Scruffing too tight, skin loose
- Pull skin away from around eyes
- Eyes pop out
Describe the integument of fish
- Semi-waterproof barrier
- Helps maintain fluid and salt balance
- Consists of epidermal cells and scales
- Covered by protective outer mucus cuticle
- Fins modified structures of skin, aid locomotion and balance in water
Describe the epidermis of fish
- Stratum basale and stratum germinatum (no corneum or spinosum)
- Mucus producing goblet cells
- Cuticle of mucus and contains antibodies and lysosymes
- Capable of cell division at all levels, during wound healing migrate rapidly to cover any defect and maintain waterproof integrity
Describe the dermis of fish
- Superficial stratum spongiosum, deeper stratum compactum
- Contains chromatophores, mechanoreceptors, chemoreceptors, electroreceptors
Describe the scales of fish
- Embedded in dermis
- Covered by layer of epidermis
- Loss of scales will almost always damage skin leading to osmotic balance problems
Give some specialised derivatives of scales in fish
- Spines
- Stings
- Bony plates
- Lateral line system
