Comparative Anatomy - Integumentary

Skin, hair, claws, pads, and mammary glands

What is the common integument composed of?

Barrier

What are the common integuments served as?

Arrector pili muscle and cutaneous muscle

What are the 2 muscles of the skin?

Arrector pili muscle

• Also called a hair muscle

Arrector pili muscle

• Band of smooth muscle attached to papillary layer of dermis of surrounding tissue sheath of hair follicle

Arrector pili muscle

• Well-developed in dorsal origin of neck, back, and tail

Arrector pili muscle

• Responsible for erection of hairs in response o cold, feat, or anger

Cutaneous muscles

• Examples include sphincter coli superficialis, platysma, and sphincter coli profundus

Sphincter coli superficialis, platysma, and sphincter coli profundus

What are the examples of cutaneous muscles?

Cutaneous trunci muscle

• Large cutaneous muscle

Cutaneous trunci muscle

• Occurs in region of thorax up to abdomen

Glands of the Canine Skin

• Sweat, sebaceous, ceruminous, circumanal, anal sac glands

Sweat, sebaceous, ceruminous, circumanal, anal sac glands

What are the glands of the canine skin?

Sweat gland

• Has Eccrine and Apocrine

Eccrine

• Found only in FOOT PADS

Eccrine

• Has watery secretion

Apocrine

• Mainly associated with hair follicles

Eccrine and Apocrine

What are the two types of sweat glands?

Sebaceous glands

• Has oily secretion in association with hair follcile

Sebaceous glands

• Found in eyelids, meibomian or tarsal glands

Eyelids, meibomian or tarsal glands

Where are sebaceous glands found?

Glands of ear canal/Ceruminous glands

• Secretes brown waxy material called cerumen

Cerumen

What is this brown waxy material secreted by ceruminous glands?

Circumanal glands

• Numerous in the vicinity of the anal orifice

Anal orifice

In what vicinity are these circumanal glands found numerous?

Glands of anal sac

• Pair sacs that lie 4 and 8 o'clock position of anal canal

Anal sac and sebaceous glands

• Glands whose combined secretions lead to formation of viscous, liquid, or pasty material with foul odor

Viscous, liquid, or pasty

What kind of material is formed when secretions of anal sac and sebaceous glands are combined?

Specialized glands of skin

• Carpal, circumoral or perioral, inguinal sinus, infraorbital sinus, interdigital sinus, nasal skin, horn glands

Carpal, circumoral or perioral, inguinal sinus, infraorbital sinus, interdigital sinus, nasal skin, horn glands

What are the specialized glands of skin?

Carpal glands

• Specialized gland of skin for pigs

Carpal glands

• Proximal to the carpus on the caudomedial side of legs that produces pheromones

Pigs

What animal has carpal glands?

Pheromones

What does the caudomedial side of legs in pigs produce in carpal glands?

Circumoral or perioral glands

• Specialized gland of skin for cats

Circumoral or perioral glands

• Located in the skin around the mouth for marking

Circumoral or perioral glands

• Also known as "cleaning glands"

Cat

What animal has circumoral or perioral glands?

Glands of inguinal sinus

• Specialized skin of sheep on either side of udder or scrotum

Glands of inguinal sinus

• Its odor may help lamb locate the udder

Sheep

What animal has inguinal sinus?

Glands of infraorbital sinus

• Specialized gland of skin for sheep found in infraorbital sinus, rostral to the eye

Glands of infraorbital sinus

• Used for marking

Sheep

What animal has glands of infraorbital sinus?

Rostral

Pertaining to the eye, in what directional term do the glands of infraorbital sinus found?

Glands of interdigital sinus

• Specialized glands of skin for sheep between digits

Glands of interdigital sinus

• Used as "trail makers"

Sheep

What animal has glands of interdigital sinus?

Glands of nasal skin

• Specialized gland of skin for artiodactyls (even-toed animals) in the skin of nose

Artiodactyls

What animals have glands of nasal skin?

Horn glands

• Specialized gland of skin for goats and some sheep caudal to the base of horn (similar location of hornless animals)

Goats and some sheep

What animal(s) has horn glands?

Hair (Pili)

• Slender keratinous filaments that cover almost all parts of body

Hair (Pili)

• Denser in dorsal and lateral parts of body

Hair (Pili)

• Thinner in areas of abdomen, inside of flanks and ears, and underside of tail

Hair (Pili)

• Continuously shed and replaced

Parts of Hair

Shaft (scapus pili) & Root (radix pili)

Shaft (scapus pili) & Root (radix pili)

What are the parts of hair?

Shaft (scapus pili)

• Portion above surface of skin

Root (radix pili)

• Embedded portion in a tubular invagination of epidermis called hair follicle which extends down to dermis

Hair follicle

In the radix pili, what is the tubular invagination of epidermis called?

Claws (unguicula)

• Modification of epidermis as horny covering of distal end of third phalanges of digits

Claws (unguicula)

• Heavily pigmented, curved, and laterally compressed

Claws (unguicula)

• Grows rapidly, and thus should be trimmed regularly to avoid long circular claw that may pierce the area between base of claw and footpad

Regularly

How often do claws have to be trimmed?

Parts of a claw

• Sole, two walls, central dorsal ridge

Sole, two walls, central dorsal ridge

What are the parts of a claw?

Central dorsal ridge

• A part of a claw that has a thicker horny material

Digital pads

• Akin to the nasal skin, it is heavily pigmented and toughest region of canine skin

Digital pads

• Where its rough surface of pads is due to the presence of heavily keratinized conical papillae

Heavily keratinized conical papillae

What is the cause of the rough surface of pads in digital pads?

Mammary glands

• Where there is a presence of mammae

Mammae

• A characteristic of mammals providing nourishment to the young

Male

What sex has rudimentary mammary glands?

Female

What sex has continually developing mammary glands especially during pregnancy and lactation?

Chestnuts and Ergots

• Normal in Horses; considered healthy growth found on most horse legs

Cattle

• Horns located at caudolateral end of the head

Cattle

What animal(s) has its horns located at caudolateral end of head?

Sheep and goats

• Horns located behind orbits

Sheep and goats

What animal(s) has its horns located behind orbits?

Polled

• Ruminants not having horns

Ruminants

What are these animals called when they do not have horns?

Pregnancy grooves

• Occurs in cows

Pregnancy grooves

• Grooves (corneal rings) on external surface of the horns, caused by slowing of growth near end of gestation and during lactation

Near end of gestation and during lactation

During what periods are the slowing of horn growth occur?

Annual pregnance

• By assuming this, you can estimate a cow's age

Annual pregnance

• Counting number of rings and add to age of first pregnancy

Cornual rings

• In sheep and goats

Cornual rings

• Circumferential grooves on the horn

Cornual rings

• More distinct than that in cows

Cornual rings

• 9-12 of these are produced per year