integument

• Common integuments include skin, claw, hair, nail, and glands located in the skin and pads
• The skin covers the outside surface of the animal, gives rise to adnexa, has no blood supply but has nerves, and takes supply from the dermis
• The epidermis is cornified, stratified squamous epithelium whose thickness is adapted to the treatment it receives
• The dermis consists essentially of feted connective tissue fibers, serving as the soft tissue structure of the integument and the raw material of leather
• The dermis is thickest in cattle, thinnest in sheep and cats
• The subcutis, also known as superficial fascia or hypodermis, is loose connective tissue underneath the skin layers
• The panniculus adiposus is the fat present in the hypodermis, especially notable in the backfat of pigs
• The skin's ridges (cristae cutis) form fingerprints and are distinct in areas without hair
• Tactile receptors are present in skin with knob-like projections
• Sinus cutanei are specialized skin pouches
• Apocrine glands are more numerous in animals than in humans
• Animals like primates, monkeys, apes, and horses have the ability to sweat
• Skin glands, haircoat, footpad, enclosure of the distal phalanx, and horn are the 5 adnexa of the skin
• Sweat glands are divided into eccrine and apocrine types, with apocrine providing the individual odor of each animal
• Eccrine sweat glands are not associated with hairs and secrete more watery sweats, predominating in primates and located in the footpad of dogs
• Sebaceous glands are widely distributed and always associated with hair follicles, producing fatty or oily secretions that lubricate and waterproof the skin and coat
• Meibomian glands are sebaceous glands located on the tarsal glands of the eyelids
• Sebaceous glands in pigs are sparse and rudimentary, while in avian species, they are present, especially in aquatic animals for waterproofing
• Preening is the water-proofing behavior of avian species to distribute oil
• Circumanal glands are specialized skin glands restricted to the vicinity of the anus
• Anal sac glands or perianal glands are specialized skin glands that are sebaceous and serous in nature, found beside the anus of carnivores
• Tail glands are diamond-shaped, located at the dorsum of the tail in cats, and rudimentary in dogs
• Tail glands are located in the 7th and 9th caudal vertebrae
• Horn glands are active during the breeding season of goats
• Inguinal pouch glands' function is for lambs to look for the udder
• Mammary glands secrete milk in bilaterally symmetrical order to either side of the midline on the ventral aspect of the trunk
• Mammary glands are also known as mammae in pigs and carnivores, and as udders in ruminants and horses
• The blood supply of mammary glands includes the cranial epigastric artery, internal thoracic artery, and caudal superficial epigastric artery
• Thoracic and cranial abdominal mammary glands drain into the axillary lymph nodes, while caudal abdominal and inguinal mammary glands drain into the superficial inguinal lymph nodes
• Bitches and queens have 10 mammary complexes, each having 5-20 mammary units, while sows have 14 mammary unit complexes, each having 2-3 mammary units
• Ewes and nannies have mammary glands restricted to the inguinal region, with 2 mammary complexes, each having a single mammary unit
• Cows have 4 mammary complexes, each having a single mammary unit
• The udder is divided into quarters by a prominent median intermammary groove
• Mares have a small udder in the inguinal region with two mammary complexes, each having 1 mammary unit
• The hoof wall consists of:

  • Toe (front)
  • Quarters (sides)
  • Medial and lateral heels (back)
  • The side of the hoof wall is sharply inflected to form the "bars"
• The ground surface of the hoof includes:

  • Solar Margin (Margo Solearis)
  • Sole (Solea cornea; fills the space between the wall and the frog)
  • Frog (cuneus corneus; occupies the space between the bars, flanked by the Paracuneal grooves)
  • Bulbs or heels (Torus corneus; located at the base of the frog)
• Artiodactyles are classified as having two weight-bearing digits on each foot, such as large ruminants and pigs
• Dogs have claws corresponding to the number of digits they possess
• Cats have laterally compressed, strongly curved claws that resemble a sickle, with a sharp inside curve on the blunt convex surface
• Cats actively retract their claws using elastic ligaments into the claw fold