Integument (skin) Flashcards
Skin: Epidermis Epithelium
- Stratified squamous keratinized epithelium
Skin: Epidermis Composed of
- Stratum basale
- Stratum Spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
- Stratum disjunctum
- Melanocytes
Stratum germinativum is Composed of
- Stratum basale and Stratum Spinosum
Stratum lucidum
- occurs only in non-hairy skin (foot-pad)
Melanocytes
- are located among the cells of stratum basale and spinosum
- It produces melanin which give color to the skin and hair
Stratum granulosum
- several layers of flattened cells having keratohyalin granules
Stratum corneum
- consists of dead, keratinized cells
- these cells contain a protein called keratin which provides structural support to the cell
Stratum Disjunctum
- is the most superficial layers of the stratum corneum that undergo constant desquamation
Dermis Layers
- Superficial Papillary Layer
2. A deep reticular layer
Superficial Papillary Layer of the Dermis
- dermis layer that consists of loose CT
Deep reticular layer of the dermis
- dermis layer that consists of dense irregular connective tissue
Hypodermis (subcutis)
- Adipose tissue is present either in the form of small clusters, or large mass of fat called panniculus adiposus
Panniculus adiposus
- large mass of fat in the hypodermis
Hair
- covers the entire body except:
1. Foot-pad
2. Hoof
3. Glans Penis
Hair
- flexible keratinized structure
Hair Shaft
- the free part of the hair above the surface of the skin is the hair shaft
Hair shaft components
- Cuticle
- Cortex
- Medulla
Cuticle of the Hair Shaft
- formed by a single layer of flat keratinized cells
Cortex of the Hair Shaft
- a layer of dense compact keratinized cells with their long axis parallel to the hair shaft
- pigment granules are present within the cells
Medulla of the Hair Shaft
- form the center of hair and is loosely filled with cuboidal or flattened cells
Used for medicolegal purpose
- The pattern of the surface of the cuticular cells, together with the cellular arrangement of the medulla is characteristic for each species
Hair Follicle Components
- Hair Root
- Hair bulb
- hair matrix - External Root sheath
- stratum spinosum - Internal Root sheath
- internal root sheath cuticle
- granular epithelial layer
- pale epithelial layer
Internal Root Sheath Components
- Internal root sheath cuticle
- Granular epithelial layer
- Pale epithelial layer
External Root sheath Components
- several layers of cells similar to stratum spinosum
- covered by a glassy membrane
- the entire epithelial sheath is enclosed by a CT sheath
Hair Matrix
- cells give rise to the cells that keratinized (soft form) to form hair shaft
- comparable to germinativum cells (actively dividing cells)
Arector pilli muscle
- associated with most hair follicles
- These are bundles of smooth muscle attached to
- > the CT sheath of the hair follicle
- > connect to the papillary layer of the dermis
Arector pilli muscle
- These are innervated by autonomic nerves
Sinus, Or Tactile Hair Follicles
- whiskers of the cat
- characterized by a blood-filled sinus between the inner and outer layer of the dermal sheath
Sinus, Or Tactile Hair Follicles
- highly specialized tactile hairs
- characterized by a blood-filled sinus between the inner and outer layer of the dermal sheath
- skeletal muscle for voluntary control
Sebacous Glands
- simple, or compound alveolar glands
Sebacous Glands are associated with
- Hair Follicles
2. Hairless Areas
Hair Follicles of the Sebaceous Glands
- their ducts empty to form the pilosebaceous canal
Hairless Areas of the Sebaceous Glands
- release their secretory product (sebum) by holocrine mode
- empty directly onto the surface of the skin through a duct
Sebaceous Glands of the Sheep
- Infraorbital gland
- Inguinal gland
- Interdigital gland
Sebaceous Glands of the Dog
- Preputial Gland
2. Circumanal gland
Sweat (sudoriferous) Glands
- Apocrine Sweat Glands
2. Merocrine Sweat Glands
Apocrine Sweat Glands
- simple coiled tubular sweat glands
Apocrine Sweat Glands in domestic Animals
- apocrine glands are located throughout most of the skin
Apocrine Sweat Glands in Horses
- apocrine glands secrete abundantly
- produce sweat during exercise and at high temperatures
Merocrine Sweat Glands
- simple tubular sweat glands
Merocrine Sweat Glands in Dog and Cats
- sweat gland in the foot pad
Merocrine Sweat Glands in Bovine
- sweat gland in the Planum Nasolabiale
Merocrine Sweat Glands in Swine
- sweat gland in the carpal glands
Mammary Gland
- compound tubulo-alveolar gland
Mammary Gland Myoepithelial cells
- contract in response to oxytocin which causes the letdown of milk into the duct system
Duct System Order of the Mammary Glands
- Intralobular
- simple cuboidal - Interlobular duct
- stratified cuboidal - Lactiferous sinus
- stratified cuboidal - Teat sinus and papillary duct
- stratified squamous
Digital Organ and Hoof
- consists of a keratinized portion made of hard keratin
Horses, ruminants and Pigs
- these species have hooves
Ruminats
- species have cornual horns
Dogs and cats
- species have claws, or nails
Dogs and Cats
- species that have digital pads
Digital Pads
- consist of highly keratinized hairless epidermis
- coiled merocrine glands in the dermis
- subcutaneous masses of adipose tissues enclosed in collagen and elastic fibers
Chestnut and Ergot
- composed of tubular and intertubular horn
Skin (Dermis) in birds
- completely devoid of glands(no sebaceous or sweat gland), except for the uropygial gland
Comb, Wattle and Ear Lobes in birds
- consists of double layer of skin with numerous blood vessels in the dermis
Uropygial gland, or preen gland
- produces an oily substance that is released by the holocrine mode of secretion to protect the skin and feathers
Eye Tunics
- Fibrous Tunic
- Vascular Tunic
- Nervous tunic
Fibrous Tunic
- sclera and cornea
Vascular Tunic
- choroid, ciliary body and iris
Nervous Tunic
- retina
Sclera
- part of the fibrous tunic
- a white layer of dense irregular CT
- bundles of collagen fibers having few elastic fibers are arranged parallel to the
surface of the eye ball
Cornea
- stratified squamous non-keratinized epithelium
Cornea Layers
- Anterior epithelium
- Subepithelial basement membrane
- Substantia propria
- Posterior limiting membrane
- Posterior epithelium
- corneal endothelium
Choroid
- highly vascularized layer of the eyeball
- composed of a dense network of blood vessels embedded in the heavily pigmented CT
Tapetum lucidum
- in the dorsal half of the fundus of the eye ball, the choroid has this light-reflecting area
- this makes the eyes of the animals “shine” when they look towards light
Tapetal Cells of the eye
- contain crystalline rods which are responsible for light reflection
- this makes the eyes of the animals “shine” when they look towards light
Ciliary Body of the Eye
- the rostral continuation of the choroid
Iris of the Eye
- composed of highly vascularized CT and pigmented epithelium
- “the color of the iris determines the color of the eye”
Color of the Iris
- determines color of the eye
Nervous Tunic of the Eye
- retina
Nervous Tunic Components
- Pigment Epithelium
- Photoreceptive Layer
- External Limiting membrane
- Outer nuclear layer
- Outer plexiform layer
- Inner nuclear layer
- Inner plexiform Layer
- Ganglionic cell layer
- optic nerve fiber layer
- Internal limiting membrane
Photoreceptive Layer Components
- Rods
2. Cones
Rods
- concerned with black and white (night)
Cones
- concerned with the color day vision
Cataract
- the lens in older animals becomes cloudy and affects their vision
Lacrimal Gland in ruminants
- lacrimal gland is predominantly serious
Lacrimal Gland in cats
- lacrimal gland is serious
Lacrimal Gland in Dogs
- lacrimal gland is sero-mucous
External Ear Components
- Auricle (pinna)
2. External Auditory Canal
Middle Ear Components
- Auditory Ossicles
- Tympanic cavity
- Auditory Tube
Auditory Ossicles
- Malleus Bone
- Incus Bone
- Stapes Bone
Internal Ear
- Bony Labyrinth
2. Membranous Labyrinth
Bony Labyrinth
- filled with perilymph
Membranous Labyrinth
- filled with endolymph
Cristae ampullaris, macula utriculi and macula sacculi
- Responsible for the vestibular (balancing) mechanism in the membranous labyrinth
Crista Ampullaris of the membraneous labyrinth
- in the ampulla
- composed of sensory epithelium
Organ of Corti
- spiral organ
- in cochlear duct for hearing
Organ of Corti Contains
- Sensory Cells
- Afferent and efferent nerve terminals
- Tectorial Membrane
Bony Labyrinth
- Semicircular canal
- Vestibule
- Cochlea
Membranous Labyrinth
- Semicircular Ducts
- Utericle and Saccule
- Cochlear Duct
Crista Ampullaris
- is composed of sensory epithelium that project into an overlying glycoprotein layer cupula
Macula utericle and sacculi
- have sensory epithelium, penetrate in to gelatinous mass which has calcium carbonate crystal called otolith