Integumentary System Flashcards
the process of cells dying in order to form the vital protective barrier that helps enable the animal’s survival
Keratinization
What is another name for the Integumentary System
The Common Integumentary System
List the 7 functions of the Integument
- Prevent desiccation
- Prevent infection
- Thermoregulation - vasoconstriction vs vasodilation
- Excretion - water, salt, organic wastes
- Sensation - touch + pressure > input to CNS
- Vitamin D synthesis
- Storage - nutrients
the outer, non-vascular layer of skin that acts as a waterproof shield
Epidermis
the deep, vascular layer of skin that makes up the majority of skin
Dermis
the 3rd layer of the integument that acts as a thermoinsulator and a mechanical shock absorber
Hypodermis (Subcutaneous Layer)
separates the two layers of the integument
Epithelial Basement Membrane
What are the 4 components of the common integument?
- Epidermis
- Dermis
- Hypodermis
- Epithelial Basement Membrane
cells in the epidermis that produce a tough, fibrous, waterproof protein that gives skin its resiliency and strength
Keratinocytes
What are the majority of cells found in the epidermis?
Keratinocytes
long-reaching cells in the epidermis that produce pigment to be used by keratinocytes
Melanocytes
a dark pigment stored in membrane bound granules that is used to protect keratinocytes from UV rays
Melanin
membrane-bound granules that store melanin
Melanosomes
epidermal-specific macrophages that phagocytize microinvaders and stimulate other aspects of the immune system
Langerhans Cells
half-dome cells found at epidermal-dermal junctions that aid in the sensation of touch
Merkel Cells
the combination of a Merkel cell and a sensory nerve ending
Merkel Disc
What 3 types of cells are commonly affected in skin cancer?
- Squamous Cells
- Melanocytes
- Basal Cells
List 3 common skin cancers seen in vet med
- Malignant Melanoma
- Squamous Cell Carcinoma
- Basal Cell Tumors
a deadly form of skin cancer that results from abnormal changes in the genetic programming of melanocytes
Malignant Melanoma
What species is commonly affected by Malignant Melanoma? What 3 locations do the nodules appear?
- Aged grey horses
- Under tail base, in perianal areas, in the scrotum
a malignant form of skin cancer that is aggressively invasive locally, particularly to local lymph nodes
Squamous Cell Carcinoma
What visible symptom does squamous cell carcinoma produce?
circular, ulcerated lesions
Squamous cell carcinoma is common in what 5 species?
- Dogs
- Cattle
- Horses
- Cats
- Merino ewes
slow-growing tumors that stem from the basement layer of the epidermis, in hair follicles, and in sebaceous glands that do not spread but are recurrent
Basal Cell Tumor
What is the most common tumor found on cats?
Basal Cell Tumor
List the 5 layers of a Furless Epidermis from deepest to most superficial
- Stratum basale (basal layer)
- Stratum spinosum (spiny layer)
- Stratum granulosum (granular layer)
- Stratum lucidum (clear layer)
- Stratum corneum (horny layer)
How many layers do fur-covered and furless epidermises have?
Fur-Covered = 3
Furless = 5
knoblike elevations throughout the epidermal surface that are associated with special hairs important in the perception of touch
Tactile Elevations (epidermal papillae)
special hairs important in the perception of touch
Tactile Hair (tylotrich hairs)
dermatitis caused by tiny mites that live on or in the skin and results in irritation, pruritus (itchiness), and alopecia
Mange
How do you diagnose mange?
- Scrape skin with a DULL scalpel blade
- Transfer scrapings to a microscopic slide
- Examine via microscope
- Diagnose which type of mite it is
long, thin, mange-causing mites with stubby legs that live in hair follicles and sebaceous glands
Demodex Mites
round-bodied, mange-causing mites that burrow into oozing raw patches of the skin and result in agonizing itchiness
Sarcoptes
the species of mite that causes scabies or mange in humans, dogs, foxes, horses, and cattle
Sarcoptes scabiei
small, round-bodied mites that burrow into oozing raw patches of the skin and are common in cats, rats, and rabbits
Notoedres
What are the 3 types of fibers found in the dermis?
- Collagen Fibers
- Reticular Fibers
- Elastin Fibers
What are the 2 layers of the dermis?
- Papillary Layer - superficial
- Reticular Layer - deep
Why are tension lines important for surgeons?
Incisions heal best when made in the direction of the bundles > fewer fibers are disrupted > less scar tissue is needed for healing
references on the skin that indicate the separations between collagen fiber bundles of the dermis
Tension Lines
references on the skin that indicate areas of bending, typically in joints
Dermal Folds (Flexure Lines)
permits the skin to move freely over underlying bone + muscle without putting tension on the skin that would result in tearing
Hypodermis (Subcutaneous Layer)
a type of touch receptor sensitive to heavier pressure that is found in the hypodermis
Pacinian (Lamellated) Corpuscle
the presence or absence of melanin granules in the armlike extensions of the melanocytes
Pigmentation
Where do keratinocytes arrange melanin and why?
- on the side of the cell with the most sun exposure
- melanin protects from UV rays
the hormone that dictates the level of pigmentation by controlling the dispersion of melanin granules
Melanocyte-Stimulating Hormone
What type of papillae and sweat glands are found on and in paw pads?
- Conical papillae
- Eccrine Sweat Glands
foot pads that reside on the caudal surface of the “wrist”
Carpal Pads
the central weight-bearing pads of the feet
Metacarpal + Metatarsal Pads
foot pads that protect each of the digits
Digital Pads
the top of the nose in cats, pigs, sheep, and dogs
Planum Nasale
the muzzle of cows and horses
Planum nasolabiale
dark brown, horny structures on the inside of each leg at the carpus of the forearm and at the tarsus of the hind leg
Chestnuts
dark brown, horny structures found in the fetlock
Ergots
infoldings of the skin containing fine hairs, sebaceous glands, and oil glands that are primarily found on sheep
Cutaneous Pouches
List the 3 types of cutaneous pouches commonly found on sheep
- Infraorbital Pouches
- Interdigital Pouches
- Inguinal Pouches
infoldings of the skin found in front of the eyes of sheep
Infraorbital Pouches
infoldings of the skin found between the digits above the hooves of sheep
Interdigital Pouches
infoldings of the skin found in the groin of sheep
Inguinal Pouches
Where is hair thickest and thinnest on the animal body?
Thickest - back + sides
Thinnest - abdomen + medial side of proximal limbs
the part of the hair that is visible above the skin
Shaft
the part of the hair buried within the skin
Root
an invagination of the epidermis that extends from the skin surface to the dermis or hypodermis and anchors the hair
Hair Follicle
the expanded and deepest part of the hair follicle
Hair Bulb
rapidly dividing epithelial cells that get nourishment from the blood vessels in the papilla
Matrix
a vascular mound of dermal cells at the base of the hair bulb that is covered in and nourishes the matrix
Papilla
a web of nerve endings enveloping the root that act as a touch receptor when the hair is bent
Root Hair Plexus
an epidermal orifice
Pore
follicles in which multiple hair strands emerge from a single pore
Compound Follicle
multiple, shorter hairs found in compound follicles that surround the guard hair
Secondary Hairs
the innermost layer and central core of hair
Medulla
the middle layer of hair
Cortex
the outer layer of hair
Cuticle
Volume of shedding depends on what 3 things?
- Genetics
- Environment
- Hormonal changes
the phenomenon in which bitches lose a large percentage of their total hair volume at once after whelping
Telogen Effluvium (blowing the coat)
the phase of the hair cycle in which cells are continually added to the base of the root, pushing the keratinized epithelial cells away from the papilla, and the hair lengthens
Anagen Phase
the transition period between the growth and rest phases of the hair cycle
Catagen Phase
the phase of the hair cycle in which the maximum length of hair is achieved, the hair stops growing, and the hair follicle shortens
Telogen Phase
Different coat colors are affected by what 4 things?
- Quantity of melanin - high vs low
- Location of melanin - uniform throughout vs bands of pigmentation
- Type of melanin - depends on species
- Age - melanin product decreases
pigmentation in which bands of melanin are formed in hair
Agouti Coloring
How many types of melanin are produced by horses and dogs?
Horse - 1
Dogs - 2
a type of melanin produced in dogs that results in yellowish and reddish colors
Pheomelanin
a type of melanin produced in dogs that result in brown-black colors
Tyrosine Melanin
a type of hair that is straight or arched, long, and thick and are the dominant hairs in a complex hair follicle
Primary (Guard) Hairs
a type of hypersensitive hair that is used as feelers due to their sensory endings and can be found around the mouth and the muzzle of many species
Tactile (Sinus) Hairs
the degree of hair erection that varies between species
Implantation Angle
a small, smooth muscle attached to each hair follicle, innervated by the sympathetic nervous system, that allows animals to make their hair stand up beyond their normal implantation angle
Arrector Pili Muscle
a type of allergy caused by inhalant particles such as pollen, dust, and mold spores that can be seasonal or year-round
Atopy
the white, semiliquid mixture of cellular debris and the oily substance produced by the gland’s alveoli that coats the hair in order to prevent excessive drying
Sebum
the substance produced by the holocrine sebaceous glands of sheep
Lanolin
a type of sweat gland that empties directly onto the surface of the skin
Eccrine Sweat Gland
a type of sweat gland that empties into hair follicles
Apocrine Sweat Gland
infection of the ear canal
Otitis externa
an oval region of coarse, oily hairs located at the dorsal base of the tails of felids and canids that aids in the recognition and identification of individual animals
Tail Glands
Glands sensitive to changes in sex hormone levels and are active during puberty and estrus
Tail Glands
a reservoir of secretions that are used to transfer the musk of the animal to the environment
Anal Sacs
hard outer coverings of the distal digits that contains internal vascular tissue
Claws
the internal, vascular tissue of claws that grows from the distal end of the bone
Quick
What species have retractable vs nonretractable claws?
Most species - nonretractable
Cats - retractable
the amputation of the 3rd phalanx in cats that is usually limited to the front feet
Declawing
the remains of digits that have regressed in the course of evolution
Dewclaw
hoofed animals
Ungulates
Scientific name for the hoof
Ungula
innervated and vascular underlying tissue in claws and hooves
Corium
innervated and vascular tissue located between the hoof wall and the 3rd phalanx that provides nutrients to the stratum internum
Laminar Corium
innervated and vascular tissue located in the perioplic sulcus that supplies nutrients to the overlaying periople
Perioplic Corium
innervated and vascular tissue located in the coronary sulcus and provides nutrients to the stratum externum and stratum medium
Coronary Corium
innervated and vascular tissue located superior to the sole and provides nutrients to the sole
Sole Corium
innervated and vascular tissue located superior to the frog and provides nutrients to the frog
Frog Corium
Where does the hoof continuously grow from?
The coronary band
the combination of primary and secondary interdigitations that increase contact between the corium and the hoof wall in order to attach the hoof and the coffin bone
Laminae
Horseshoes have what 4 functions?
- Prevent excessive hoof expansion, chipping, or cracking
- Improves traction
- Creates additional barrier between the hoof + ground
- Allows horses to be kept in working condition with more regularity
the convex, external portion of the hoof that is visible from the anterior, lateral, and medial views
Hoof Wall
the front of the hoof wall
Toe
the lateral aspects of the hoof wall
Quarters
the portion of the hoof wall that tapers downward and wraps around the back of the foot
Heels
the concaved, innervated, vascular portion of the hoof that fills the space bordered by the walls and the bars and is located on the palmar or plantar surface of the hoof
Sole
the part of the sole that immediately surrounds the bars
Angle
a thin strip at the junction of the sole and the hoof wall
White Line
the insensitive, horny structure located between the heels on the underside of the hoof that is V-shaped
Frog
the portion of the frog that faces the toe
Point (apex)
the portion of the frog that runs across the caudal aspect of the foot between the heels
Base
divides the frog
Central Sulcus (cleft)
a deep, concave region that separates the frog from the lateral and medial sides of the bars
Collateral Sulcus
the thick pad of fat and fibrous tissue beneath the frog
Digital Cushion
the junction of the sole and the frog where the wall turns in from the posterior part of the foot and melds with the frog
Bars
the soft tissue that covers the heel of the foot just behind the frog
Bulb
2 large bands that extend proximally from the distal phalanx and act as structural support for the equine foot and work with the frog and digital cushion to pump blood through the foot
Lateral Cartilages
What are normal hoof angles of the front feet vs hind feet?
Front Hooves - 50º
Hind Hooves - 55º
keratin masses that emerge from processes of the frontal bones that are epidermal in origin
Horns
Antlers and horns are found on which sex?
Antlers - males
Horns - both
hollow extension of the frontal skull bone that communicates with the frontal sinus cavities
Horn Core
used to manage the horn length of domestic sheep, goats, and cattle
Dehorning Process
breeds of domestic animals that are bred to be horn free
Polled Breeds
breeds of animals with horns that are not sex-specific
Nonpolled Breeds
bony protuberances that emerge from the skull and are dermal in origin
Antlers
excruciating inflammation of the laminar corium that causes a weakened connection between the hoof and the coffin bone and ultimately can result in the coffin bone slipping to rotate downward
Laminitis (Founder)
Explain the physiological effects of laminitis
Rigid hoof cannot expand to accommodate swelling internally > laminae compresses > inhibits blood flow + circulation in foot > laminae degenerates > coffin bone pulls away from the hoof wall > bone rotates downward > pushes against the sole > can perforate the sole > death in the animal
What are 4 predisposing factors to laminitis?
- Engorgement of foods high in carbs
- Any systemic illness or condition that might lead to endotoxemia
- The postoperative period > recumbent for extended periods
- Adverse reaction to drugs
List 4 warning signs of laminitis
- Shift weight away from front feet to hind legs > alleviate pressure in the toe
- Gait is slow + hesitant
- HR + RR elevated > from the pain
- Strong pain response from a mild tap on the toe with hoof testers
What 2 locations are motor nerves found in the skin?
- Arrector pili muscles
- Blood vessel walls