Integument, muscles. senses

• protection
• thermoregulation
• hydration
• excretion of water, salts and organic wastes
• sensory organ
• engaged in synthesis of vitamin D and storage of nutrients

• largest and most extensive of systems.  Barrier between inside and out.
• Contains connective tissue, epithelial tissue, muscle tissue and nervous tissue. 
• skin, skin glands, hair, claw, hoof, horn

• keratinocytes
• langerhans
• melanocytes
• merkel cells

separates dermis from epidermis

• Majority of cells of epidermis. 
• Grow and divide along basement membrane (between d and e)
• keratinization
• strength

• cell in epidermis
• macrophages.  Eat invaders

• cell in epidermis
• produce melanin

• cell in epidermis
• at junction of epidermis and dermis
• sensory (touch)

• (Top to bottom)  Stratum corneum
• stratum lucidum
• stratum granulosum
• stratum spirosum
• stratum germinativum or stratum basale

• base layer of epidermis
• single row of keratinocytes (cell division)
• merkel cells and melanocytes also found here

• spiny layer.  second from basement membrane (between basale and granulosum)
• prickle cells
• desmosomes (hold cells together)
• infrequent divisions
• Langerhans cells (lots)

• granular layer of epidermis (between spinosum and lucidum)--middle
• 2-4 layers, glattened diamond-shaped keratinocytes
• keratinize and die.  Fill with granules (waterproof)

• clear layer. 
• only in thick skin (foot pads.  Not in most skin)
• translucent layer composed of a few rows of flattened, dead cells

• horny layer.  Outermost. 
• Dominates the epidermis (75%)
• composed of 20-30 rows of dead keratinocytes. 
• Dander

• layers.  thin areas may lack a few layers. 
• no blood or lymph vessels
• nourished by diffusion (further away = dead

• stratum basale
• stratum spinosum
• stratum corneum

• greatest portion of integument
• strength of the skin
• primarily fibrous. 
• Elastic (connective tissue), vascularized (blood vessels), innerated (nerves)
• 2 layers (Papillary and reticular)

papillary (top) and reticular (deep)

sensitive to light touch.  Found in papillary dermis. 

top layer of dermis.  Loose areolar connective tissue.  Has meissner's corpuscles. 

• dense irregular connective tissue. 
• bottom layer
• fibers in parallel bundles.  Direction based on skin tension. 

• below dermis.  Not part of skin (sub Q)
• rich in blood, lymphatic vessels and nerves. 
• missing/thin where skin is firm: lips, eyelid, etc. 
• lets skin move over bone. 
• Contains pacinian corpuscles

sensitive to heavy pressure.  Found in hypodermis

• in dermis, with some overlap into epidermis
• Sympathetic nervous system
• ennervates blood vessels, sweat glands and erector pili muscle.

none found in epidermis.  Present in dermis and hypodermis

• contains conical papilla (rough feel)
• outer skin (stratum corneum) thickest in body
• contains all five layers of skin
• Pacinian corpuscles and exocrine and sweat glands. 

• 4 digital (distal)
• metacarpal/metatarsal (big one)
• another digital (forelimb only, proximal to metacarpal)
• carpal pad (forelimb only

• dog-type nose.  Separated from muzzle. 
• 3 layers, no granulum or lucidum.  Corneum is 3-8 layers (thin). 
• Deep surface grooves look scale or plate-like
• no glands--moist from licking. 

muzzle (like a horse or cow--nose is part of mouth-area.  Not like dog)

Dark horny structure on fetlock of horse/pony/equine. 

Dark horny structure on carpus and tarsus of horse/pony/equine. 

• cutaneous pouches are infoldings of skin
• infraorbital
• interdigital
• inguinal

horn gland

carpal gland

• maintaining body temperature by trapping insulating layer of air, dark absorbs light
• protection
• camouflage (spots on fawn)
• Sex recognition (mane or beard)
• aggression display

Thickest on back, thinnest in groin

• epidermal in origin (infolding of epidermis to make pore), extends to dermis or hypodermis
• not a source of hair, assists with chemicals.

little black sac at very base of hair bulb

grows/makes the hair.  fat part of bulb

• hair
• internal root sheath
• external root sheath (production of sebaceous gland)
• dermal or connective root sheath

• medulla: center, soft keratin, flexible.  Polar bears have air instead.  Wool hairs don't have
• Cortex: stiff, rigid.  Hard keratin.  Center layer
• Cuticle Cell: one layer of keratin.  Outside (meets up with inner root sheath)

• primary/guard hairs
• secondary/wool hairs
• tactile/sinus hairs

• generall dominant hair in complex follicle
• makes up smooth outer coat

undercoat.  Softer and shorter than primary hairs.  Dominant in wooly animals.  More in winter (different animals have different)

several hairs in one pore.  Each have own follicle/bulb. 

• sinus hairs or whiskers. 
• Used as probes or feelers
• sensitive to touch
• blood-filled sinus around the base
• follicles are deeper in. 
• venus sinus and nerve endings the first things to develop

• anagen
• catagen
• telogen
• repeat

• Division of epithelial cells covering the dermal papilla generates the hair itself
• time of growth
• epithelial cells push up and away from dermal papilla (layers make up the hair shaft and root)

• period of transition between anagen and telogen. 
• Detaches from matrix.  Held in by friction (detaches easily)

resting phase.  The hair doesn't grow but stays attached while the dermal papilla is resting. 

• genetics
• environment (responds to temperature change, day length, nutrition)
• hormonal changes: telogen effuvium (blowing the coat).  Loses lots of fur after whelping to form the nest

melanocytes in cortex and medulla

• muscle that makes hair stand up when frightened or cold 
• Sympathetic nervous system
• forces sebum onto skin. 
• attaches to bulb

•  oil producing glands all over body except specialized regions (paw pads, planum nasale)
• dump into hair follecule or directly onto skin
• external root sheath in dermis
• simple or complex alveolar structures (duct portion does or does not branch)
• Some "marking" glands, in pouches
• arrector pili forces sebum onto skin

holocrine

oily liquid substance.

• traps moisture in
• keeps skin soft, pliant and somewhat waterproof
• antifungal and antibacterial properties

sheep sebum.  Aids in shedding water from coats.

where mucous membranes and skin come together.  Lips, vulva, labia.  A place sebaceous glands drop sebum directly onto the skin

• sudoriferous glands.  Throughout the body
• Apocrine and Eccrine

• type of sweat or sudoriferous gland
• Coiled excretory portion buried in dermis or hypodermis with single excretory duct that empties into HAIR FOLLICLE
• predominate in domestic species

• sweat or sudoriferous gland
• coiled tube in dermis and hypodermis with long duct that empties ON SURFACE OF SKIN
• Dogs: connective tissue of footpads

Apocrine

• Dorsal base of tail in cats and dogs
• contains many apocrine and sebaceous glands
• sensitive to changes in sex hormones

powerful smelling collection of glands in the male musk deer and skunk

• collection of glands with 1 duct that leads into anus. 
• In cats and dogs, similar to musk glands in deer and skunk. 
• 4 and 8 o'clock position relative to anus
• mark territory and attract a mate
• can rupture and cause and abscess

• a modified sweat gland in two parts that nourishes the young. 
• Comprised of mamma and teat

more medial/dorsal/proximal part of mammary gland.  The glandular structure

• the more ventral/lateral/distal part of the mammary gland. 
• a surface papilla

• man, monkey, elephant---thoracic
• cat---thoracoabdominal
• dog and pig---thoracoabdominalinguinal
• ruminant and equine----inguinal
• horse*: 2 teats
• Cat*: 8 teats
• Dog*: 10 teats

separates halves of udder

term designated for the mammae in ruminant and mare

the four parts of the bovine udder, each associated with one teat

• Alveoli (grape-like clusters of glandular tissue)
• Intralobular duct
• interlobular duct
• milk (lactiferous) duct
• milk (lactiferous) sinus)
• gland sinus
• teat sinus
• teat canal (papillary duct or streak canal)
• teat opening

release of milk from the breast following tactile stimulation of the nipple.  Moves milk into the collecting ducts and toward the nipple

• same number and position as females
• Ruminants: cranial surface of scrotum
• Equine: absent but if present are located beside the prepuce
• Only funtional in females

• the specialized attachment of the udder to the body.  Must be very strong--udder can weigh 100 lbs
• median suspensory ligament
• lamellae
• lateral suspensory ligament

specialized marking gland in skin around mouth of cat

caudal to the base of horn in goats and some sheep. 

Marking gland rostral to the eye in sheep and goats

Pig marking glands.  Rostral to carpus, caudal/medial part of leg.  Male marks sow when mating. 

marking glands between digits in sheep and deer.  Pawing = marking

at the covering of the penis (prepuce).  Produce smegma (bean)

gland around anus of carnivores

• curved or pointed appendage at end of digit in mammals, avians, some reptiles
• hard, often pigmented outer coverings of the distal digits
• Most animals have nonretractable.  All cats except cheetahs have retractable. 
• Cant be separated from distal phalanx

• remnants of digits that have regressed during evolution
• Dog 1st digit
• pig, cow, sheep: 2nd and 5th digits.
• Only pig has a dewclaw bone.   

• hoof
• Ruminants have 4 hooves per foot and each covers a digit

16--4 per foot, each covers a digit

4, 1 per foot (digit 3)

• sensitive layer (modified dermis) lining coffin bone. 
• rich in blood vessels to provide nutrients to developing cells in inner layers of hoof
• well innervated, sensitive to pain

• supports equine hoof.  With frog and digital cushion, keeps blood flowing through the foot. 
• At back of hoof, around around and caudal to coffin joint

• coffin bone is cloaked in a layer of corium (modified dermis) which in turn is covered by the outer cornified hoof (modified epidermis). 
• Outer layers of hoof wall, frog and sole are insensitive and avascular. 

interdigitation of corium and hoof wall.  Any physical change can effect blood flow to the hoof.  Bone shifts to cause founder or laminitis

band around top of hoof where hair stops.  Hair grows from here.  (line between furry part and hoof part)

thin waxy layer of hoof that covers outside.  shiny

convex external surface.  Seen from cranial, medial and lateral sides. 

seen from front.  Very tip

seen from lateral angle.  Sides/bottom of hoof

back/bottom.  Tapers to almost at base

back of hoof near coronary band

continuation of hoof, around outside of frog on base of hoof. 

• insensitive triangle of hoof.  Horny structure located between the heels on the underside. 
• Helps return blood from the foot to the body. 
• Point/apex at toe, base at heel. 

• plantar or palmar surface of hoof.  Avascular, lacks innervation.  Gets nutrients and nervous input from corium (like epidermis).  Corium connects sole to underside of coffin bone. 
• Concave.  Fills in from walls to bars

• thin white strip that is formed at junction of the sole and the hoof wall. 
• Needed in shoeing--drive nails outside of the white line

separates frog from bars of the hoof

cleft of frog.  Divides frog in half.  Central depression of the hoof

fat and fibrous tissue cranial/medial/proximal to the frog.  helps support hoof and return blood to body. 

• 4 digits, 2 weight-bearing, 2 dewclaw
• Similar to equine hoof: Bones (P2 and P3, navicular), wall, white line, sole, heel bulb (keritinized hoof pads for shock absorption), corium, digital cushion.
• Not similar: no frog, no bars

separates two hooves (3 and 4).  Axial (in between) or abaxial (each side)

curved extension of digital phalanx.  what the quick surrounds in the nail

thin shelf of bone that overlaps the claw and forms a band around the root of the claw.  Where the claw grows out of

declaw.  Removal of the claws in cats.  To prevent regrowth, must amputate the entire distal phalanx at the joint

• sheep, goats, cattle, antelope
• Bony core with permanent tough external covering

• deer, moose elk. 
• bony core with velvet covering.  Shed yearly

• Tiny permanent growths covered in skin, like horn-buds. 
• Giraffes, Okapi

• Permanent bony core and unique hairy covering. 
• Only in the pronghorn antelope

• epidermal covering of the cornual process of the frontal bone.  Permanent.  Vary in sex, size and shape.  Never branch. 
• Bony core covered by a sheet of keratin
• all 3 domestic ruminanats have them (cow sheep goats antelope)
• inner process lined by combined corium and periosteum.

• outgrowth of frontal bone (might be os cornu--horn bone that fuses).  Horn bud grows out as a solid structure that becomes pneumatized by about 6 months of age
• ornual diverticulum of frontal sinus

at the base of the horn is a ring of soft horn marking the transisiton from skin to horn.  Grwos out then covers with a thin shiny layer

• Cow; caudolateral end of head
• sheep and goats: behind the orbits

10 days of age (5-10 ideally).  Later and the bone becomes pneumatized and you risk cutting a whole in their head

hornless

• living bone, have velvet (vascular and innervated), branched, shed annualy, grow from pedicle off frontal bone. 
• Regulated by hormones (breeding season).  Only in cervid males except caribou.  Can be enormous--get bigger as animal gets older. 
• Tear off velvet at end of season--shiny and wood-like

simplest type of head-wear.  Paired short, unbranched, permanent, bony processes that are covered in skin and hair.  Not shed, both sexes and newborns have them.  Lie over sutures between frontal and parietal boens

deer

bony core like a cow, but with a 2-branched sheath that is shed annually.  ALways has s2 hooks. 

special type: fused mass of long, hair-like strands of keratin.  Rest on bony knob on much-strengthened nasal bone.  Lacks a bony core.  Male and female have horns of equal size. 

ear flap.  External, most visible cartilege core with skin covering

muscle

study of muscles

muscle cell

cytoplasm of a muscle cell

• cause or prevent movement
• stabilize joints
• keep sphincters closed or open
• maintain posture
• generate heat

• cardiac
• smooth
• skeletal

• Striated multi-nucleic muscle found on skeleton (most "muscles"), moves bones and generates heat. 
• Long thin striated fibers with multiple nuclei. 
• Voluntary movement.  Nerve supply necessary for function.
• Have arteries, veins and lymphs

• Striated single-nucleic, branched muscle of heart.  Pumps blood. 
• Involuntary: nerve supply modified action but not necessary for function.  Initiates its own beat.  Nervous system just change rhythm. 
• Branches=intercollated discs

• non-striated, single-nucleic, spindle-shaped cells of internal organs, blood vessels and the eye.  Produces movement in internal organs. 
• Involuntary.  Nerve supply to visceral smooth muscle modifies activity.  Nerve supply to multiunit is necessary for function

fibrous bands of collagen connecting muscle to bone.  Dense regular avascular connective tissue. 

broad fibrous connective tissue that attaches some muscle to bone or other muscles

the more stable attachement site of a muscle

the more moveable attachment site of a muscle

directly responsible for the action

opposes action of the agonist.  Directly opposite

assists the action of the agonist.  Opposes undesireable action. 

parallel.  Shaped like a strap. 

spindle-shaped muscle

muscle like a feather, with fibers going in two directions on opposite sides

feather-shaped muscle with fibers going in only one direction

feather-like muscle with fibers going in 3 or more directions/sides. 

muscle in a circle

one cell. Myofibril

bundle of muscle fibers, or myofibrils held together by connective tissue. 

encircles group of muscle fibers forming a fascicle

surrounds each muscle fiber (cell, myofibril)

encircles all the fascicles

• connective tissue sheets connecting muscle to bone
• form insertion and origin
• elastic but with tensile strength
• cushioned by sesamoids, bursae and/or sheaths

• single or multiple (trunk) nerves. 
• Nerve to fiber ration governs delicacy of movement (less nerves per fiber = more delicacy)
• stimulation leads to shortening. 
• Multiple moro units can be in one muscle

• Type I: Red
• Type II: White

Red muscle.  Contains oxygen-binding protein myoglobin, contacts slowly (slow twitch), contracts for long periods, suited for endurance, slow to fatigue

white muscle.  Absense of myoglobin, contract quickly (fast twitch), short bursts of speed and power

• oxygen storage unit.  Provides oxygen to working muscles. 
• Protein found in muscle cells of animals (diving animals have lots so they can stay submerged longer--seals, whales)

• Vary in thickness and extent.  Most are thin, broad and superficial. 
• Tense, twitch skin of lateral thorax and abdomen
• Little or no attachment to bone
• Cutaneous trunci, cutaneous colli, playsmus

cutaneous muscle (dog and cat), ventral to pinna, back of jaw/cheek, dorsal/lateral neck.  Opposite cutaneus colli.

covers dorsal and lateral ventral thorax (round the thorax muscle).  All domestics but humans have it. 

sternum to neck, external jugular.  Opposite playsmus (back of neck to jaw).  Best in equine

• masseter
• brachiocephalicus
• trapezius
• sternocephalicus
• superficial and deep pectoral
• infraspinatus
• deltoid
• latissimus dorsi
• serratus ventralis
• internal and external abdominal oblique
• middle and superficial gluteals

• control facial expressions
• enable chewing (mastication)
• move sensory structures such as the eye and ear
• support the head and allow neck to flex, extend and move head laterally

facial muscle (motor fiber of facial nerve Cn XII) controlling cheek and lips

cheek muscle (motor fibers of facial nerve Cn XII)  facial muscle

facial muscle (motor fibers of facial nerve Cn XII) controlling the eye

opens the mouth.  Caudal edge of mandible, ventral (V pointing at chin)

masseter, temporalis and medial and lateral pterygoid

closes jaw, with temporalis and medial and lateral pterygoid.  At caudal end of jaw

• syloglossus, geniglossus, hyoglossus,
• ennervated by hypoglossal nerve (Cn XII)

sling for tongue, raises floor of mouth.  Inside of "V" made by digastricus.  Fibers run transversely

extends from one place to another body structure

arise and terminate on one body structure. 

opens the glottis.  Instrisic larygneal muscle that abducts the vocal folds

larygeal hemiplagia in the horse.  Damage to one side of the glottis so that only 1/2 opens. 

• head/neck muscle.  Arm to head.  Pulls the limb forward, depresses and pulls head and neck laterally. 
• Carnivores, ruminants and pigs: 3 parts
• Equines: 2 parts

• Carnivore, ruminant, pig: 3 parts
• horse: 2 parts

• forms, along with brachiocephalicus, the jugular groove in horse and ruminants.  Just cranial to brachiocephalicus
• Depresses head and neck and/or draws the head and neck to the side

• Carnivores: 2 parts
• Ox and goat: 2 parts
• Pig and sheep: 1 part
• horse: 1 part

from first sternebra (manubrium) and first costal cartilage up the neck to insert on the hyoid apparatus.  Center of throat, over larynx

Arises from sternohyoid and inclines laterally to insert of the thyroid cartilege of the larynx (beside hyoid)

white line down ventral center of body.  Narrow stip of fascia connecting two rectus abdominus muscles.  Made of insertions of other abdominal muscles (ensheath rectus).  Cut there for surgery

• Support abdominal organs
• help flex/arch the back
• assist with expulsion of feces, urine and newborn
• assist with vomiting and regurgitation
• play role in respiration

• Along ventral rib cage. 
• Oblique muscles are arranged in layers which have their fibers running in a slanting direction opposite each other. 
• Outside layer of these muscles is External Abdominal Oblique
• fibers run caudoventrally

• Between ribs and pelvis
• Oblique muscles are arranged in layers which have their fibers running in a slanting direction opposite each other.  Middle layer of these muscles is Internal Abdominal Oblique
• Fibers run cranioventrally

• Between rib cage and pelvis
• Oblique muscles are arranged in layers which have their fibers running in a slanting direction opposite each other.  Deepest layer of these muscles is transverse abdominus
• Fibers run transversely (dorsoventrally)

• Oblique muscles are arranged in layers which have their fibers running in a slanting direction opposite each other. 
• Outside layer is External abdominal oblique, running caudoventral
• Inside layer is Internal abdomal oblique, running cranioventral
• Deepest layer is Transverse Abdominus, running dorsoventrally

6-pack muscle.  2 long straight muscles from sternum to prepuse tendon.  Aponeuroses of other muscles surround on both dorsal and ventral surfaces.

• Brachiocephalicus
• trapezius
• omotransversarius
• latissimus dorsi
• superficial pectoral
• rhomboid
• serratus ventralis
• deep pectoral

extrinsic muscle of thoracic limb.  Humerus to spine.  Flexes the shoulder, helping pull the animal forward. 

Extrinsic muscles of thoracic limb.  Superficial (major) and deep (minor).  Adductors of front legs.  Keep front legs under the animal

extrinsic muscle of thoracic limb.  Elevates and abducts the forelimb.  Triangle over dorsal scapula (2 parts--acromiotrapezius, spinotrapezius)

extrinsic muscle of the thoracic limb.  Muscle acts like a sling to support the body between the forelegs.  Serrated edge

extrinsic muscle of the thoracic limb.  Lies deep to the trapezius.  Draws the shoulder dorsocranially. 

• deltoideus
• Infraspinatus
• Supraspinatus

• subscapularis
• teres major

triceps brachii

• biceps brachii
• brachialis

• extensor carpi radialis
• common digital extensor
• lateral digital extensor
• lateral ulnar (extensor carpi ulnaris)
• abductor pollicis longus (oblique carpal extensor)

• flexor carpi radialis
• flexor carpi ulnaris
• superficial digital flexor
• deep digital flexor

intrinsic muscle of lateral shoulder.  Abducts and flexes the shoulder joint

extends the shoulder joint.  Intrinsic muscle of lateral shoulder

flexes the shoulder oint and abducts the limb at the shoulder.  Intrinsic muscle of the lateral shoulder

Intrinsic muscle of the thoracic limb.  Caudal border of the scapula.  Flexes shoulder

intrinsic muscle of the thoracic limb.  Medial intrinsic muscle.  Sits in subscapular fossa, adducts and extends the shoulder joint. 

• intrinsic muscle of the thoracic limb. 
• 3 heads in most animals (long head, medial head, lateral head)
• 4 heads (+ accessory head) in carnivores. 
• Insertion: olecranon of ulna
• extends the elbow

long, medial and lateral in most animals.  Add accessory for carnivores. 

intrinsic muscle of thoracic limb.  Distal scapula to proximal radius.  Flexes the elbow-joint.  Popeye muscle on cat. 

Intrinsic muscle of thoracic limb.  Insert on the radius.  Flexes elbow.  Origin: caudal humerus. 

biceps brachii, brachialis

triceps brachii

Intrinsic muscle of the forearm. Extends the carpuss.  Located over the radius

Intrinsic muscle of the forearm.  flexes the digits and is located beneath some of the other digital flexors. 

• Brachioradialis
• extensor carpi radialis
• comon digital extensor
• lateral digital extensor
• lateral ulnar (extensor carpi ulnaris)
• (oblique carpal extensor -- not in the row like the others)

• most cranial (always in cats, usu in dogs, not in ungulates) intrinsic craniolateral forearm muscle.  Runs along cephalic vein. 
• Supinates paw.

• intrinsic craniolateral forearm muscle from humerus to metacarpals.  Between brachioradialis and common digital extensor.  2 heads we don't care about. 
• extends carpus and flexes elbow

• intrinsic craniolateral forearm muscle.  Caudal to Extensor carpi radialis (next to lateral digital extensor).  From humerus to distal phalanges
• Splits into 4 tendons that attach to distal phalanges
• extends the carpus and digits

• intrinsic craniolateral forearm muscle that is between common digital extensor and lateral ulnar (extensor carpi ulnaris).  From humerus to proximal metacarpals
• smaller and caudal/lateral to common digital extensor.  Splits into 4 tendons that are deep to the common digital extensor's. 
• Flexes carpal joint

• intrinsic craniolateral forearm muscle that is caudal/lateral to lateral digital extensor (last of the dorsal forearms). 
• Only flexor that attaches to lateral epicondyle of humerus. 
• Flexes carpal joint

• Flexor carpi ulnaris
• Superficial digital flexor
• flexor carpi radialis
• pronator teres
• (back at extensor carpi radialis)
• Deep digital flexor (under SDF)

Between lateral ulnar and superficial digital flexor.  Most caudal.  2 heads (humerus and olecranon) (at olecranon--the muscle where you flip the arm)

• big intrinsic muscle of caudomedial forearm. 
• Divides into 4 under-wrist tendons.  (humerus to palm)
• Flexes the digits and carpus

• caudomedial forearm.  Between SDF and pronator teres.  Partly attached to DDF.  (humerus to palmer metacarpals). 
• Muscle belly only goes to middle of forearm (tendon continues).  Most cranial and medial.  Internal and hard to see. 

• Caudomedial forearm.  Obvious triangle, so good for orientation.  Humerus to medial radius. 
• Pronates the paw. 

• craniolateral forearm.  Humerus to radius (short, next to pronator teres).  Under extensor carpi radialis. 
• Supinates the paw. 

• Deep to SDF.  3 heads, connecting to the palmar surface of the digits  Humeral, radial and ulnar heads to distal phalanges (4 tendons). 
• Flexes digits and carpus. 

• oblique muscle of cranial forearm, near carpus.  Runs obliquely across the tendon of the extensor carpi radialis.
• Lies in groove between radius and ulna.   
• extends carpus and abducts carnivore's first digits.

• intrinsic forearm.  ulna to radius.  Bridges interosseus gap. 
• Pronates paw

• Internal obdurator
• external obdurator
• gemelli
• quadratus femoris
• Outwardly rotate and adduct the limb. 

• tensor fascia latae muscle
• superficial gluteal
• middle gluteal
• deep gluteal

• Biceps femoris
• semitendinosus
• semimembranosus

• sartorius
• gracilis
• pectineus muscle
• adductor muscle

• quadriceps femoris (4 heads):
• vastus lateralis
• vastus medialis
• vastus intermediate
• rectus femoris

• Cranial tibial
• Long digital extensor
• Peroneus longus

• Gastrocnemius muscle
• superficial digital flexor
• deep digital flexor
• popliteus muscle

tough white sheet of fascia attached to tensor fascia latae muscle.  Over cranial part of thigh. 

attaches to fascia lata.  Flexes hip, extends stifle

• Superficial gluteal
• middle gluteal
• deep gluteal
• (pelvis to greater trochanter of femur). 
• Extend hip, abduct limb. 

• superficial gluteal.  Extends hip. 
• Small, caudal to middle. 

middle gluteal.  Extensor of hip.  Larger and more cranial than superficial. 

• 3 big muscles in the back of the thigh.  Extend the hip, flex the stifle. 
• Pull the leg backward to PROPEL THE ANIMAL FOREWARD WHEN IT WALKS OR RUNS

• Biceps femoris
• semimembranosus
• semitendinosus
• propel animal forward when walking or running

• Gracilis (inner thigh)
• semimembranosus
• semitendinosus
• biceps femoris (outer thigh)

• Sartorius (wraps around front of leg)
• Gracilis (back of thigh)
• Pectineus
• Adductor longus
• Adductor magnus et brevis

• 4 heads (rectus femoris from ilium, other three from femur, to tibial tuberosity)
• Rectus femoris (in center of lateralis and medialis)
• vastus lateralis (behind fascia lata)
• vastus medialis
• vastus intermedius (behind vastus lateralis)
• Main extensor of stifle joint. 
• MOVES LEG FORWARD TO TAKE NEXT STEP

• most cranial muscle of distal limb.  Front of tibia.  Tendon veers off to medial side and attaches to plantar part of digits. 
• Flexes the tarsal joint

• Underneath cranial tibial.  Divides into four tendons. 
• Extends the digital joint, flexes the tarsal joint and extends the stifle joint. 

• Caudal and lateral to long digital extensor
• From proximal tibia and fibula to fourth tarsal bone and plantar metatarsals. 
• Flexes the tarsal joint

• Thin tibial muscle.  Tendon attaches to fifth digit. 
• Extends and abducts digit 5

• Under peroneus longus.  Has 2 or 3 muscle bellies, depending on species.  Caudal tibia/fibula to plantar distal phalanges
• extends tarsal joint and flexes digital joints

• only present in cat, pelvic limb, under gastrocnemius, between SDF caudal) and DDF (cranial).  Fibula to gastrocnemius
• extends tarsus

• femur to calcaneus and middle phalanges.  Deep to head of gastrocnemius. 
• Flexes stifle and digits, extends tarsus

• 2 heads, each with sesamoid bone.  Equivalent to human calf.  Femur to calcaneus. 
• Powerful extention of tarsus (hock) and flexes stifle. 
• PROPEL BODY FORWARD in taking a step. 

to increase or decrease size of thoracic cavity to draw air into and push air out of the lungs

• Muscles that increase size of thoracic cavity when they contract, drawing air into lungs. 
• Diaphragm
• External intercostal muscles
• Scalenus
• levatores costarum
• rectus thoracis
• cranial serratus dorsalis

Inspiratory muscle, thin, dome-shaped sheet of muscles that separates the thoracic cavity from the abdominal cavity

inspiratory muscle located between the ribs. caudoventral fibers.  Rotate ribs up and out.

• cervical vertebrae to first rib.  Inspiratory muscle with multiple parts.
• Under serratus ventralis. 

• lateral thorax from third to first rib.  Direct continuation of the rectus abdominus muscle.  Inspiratory. 
• Under scalenus.

• insignificant inspiratory muscle over the dorsal part of the ribs.  Tiny, hard to see. 
• Pulls ribs forward. 

• aid in pushing air out of the lungs. 
• Internal intercostal
• abdominal muscles
• caudal serratus dorsalis
• NOT DIAPHRAGM

expiratory muscles.  Deep to external intercostals.  Extend cranioventrally between adjacent ribs.  Rotate ribs backward to push air out. 

Push abdominal organs against caudal side of diaphragm to decrease size of thoracic cavity. 

• Over dorsal part of caudal-most ribs. 
• pulls ribs caudally during expiration. 

• Dorsal to transverse process of the vertebrae.  Extensors of the spine. 
• Iliocostal
• logissimus
• transversospinalis

• muscles below the transverse processes of the vertebrae.  Flexors of spine (along with rectus abdominus). 
• Major psoas
• minor psoas
• iliacus
• Quadratus lumborum

most lateral column of the epaxial muscles extending in overlapping bundles.

intermediate column of epaxial muscles from iliac crest to head (4 parts). 

most medial column of epaxial muscles

• hypaxial muscle.  Ventral cervical vertebrae to os coxae. 
• flex/stabilize back and lumbar vertebrae

• hypaxial muscle that attaches to pelvis.
• flex/stabilize back and lumbar vertebrae

• lateral to and larger than psoas minor. 
• flex/stabilize back and lumbar vertebrae

• ilium to femur.  Very close to psoas major. 
• flex/stabilize back and lumbar vertebrae

the wall and associate structures closing the pelvic outlet and surrounding the anal and urogenital canals

• External anal sphincter
• levator ani
• coccygeus

striated perineum muscle.  Voluntary.  medial-most to anal.

• perineum muscle between external anal sphincter and coccygeus. 
• Acts to compress the rectum and helps pull dog's tail between its rear legs. 

lateral-most perineum muscle.  Pulls the dogs tail between its rear legs.

• housed within temporal bones of the skull
• Organ of hearing and balance. 
• External, middle, and inner

• funnel-shaped to collect sound wave vibrations and direct them to the eardrum. 
• Pinna
• External auditory canal
• tympanic membrane

part of ear seen from outside.  Elastic cartilege and skin.  Collects sound wave vibrations and directs them into external auditory canal

L-shaped part of outer ear (outer vertical, inner horizontal).  Ends blindly at tympanic membrane. 

ear drum.  Sound waves strike it and it vibrates at the same frequency through a process called sympathetic vibration. 

tympannic membrane vibrates at same frequency as sound waves that hit it. 

cavity (hollowed-out area of temporal bone) containing 3 small bones (ossicles).  Opening of eustachian tube connects it to pharynx (throat)

• Link the tympanic membrane with the cochlea of the inner ear. 
• Malleus
• Incus
• Stapes

• auditory tube.  Part of middle ear that connects ear cavity with pharynx. 
• Equalizes air pressure on the two sides of the tympanic membrane. 

• Hearing (cochlea)
• Equilibrium (Vestibular apparatus which consist of utriculus, saccules and semicircular ducts.  Receptors in vestibule and semicircular duct)

• between cochlear and semicircular canals
• used for equilibrium
• consists of utriculus (saclike space), saccules (saclike space) and semicircular ducts.

• Inner-ear organ of hearing
• Scala vestibuli
• scala media
• scala tympani
• organ of corti

• Anterior canal
• Posterior canal
• lateral canal
• The ducts lie in three planes at right angles to each other. 

eye

• fibrous (outer)
• vascular (middle)
• nervous (inner)

• Outer layer.  Consists of cornea and sclera
• Admits light into eyeball's interior and gives strength and shape to eyeball. 

• Transparent "window" that admits light to the interior of the eye.  Part of fibrous (outer) layer of eyeball. 
• Consists of collagen fibers, pain receptors and NO BLOOD VESSELS

• The "white" of the eye.  Part of fibrous (outer) layer of eyeball. 
• Consists of dense fibrous connective tissue.  Majority of outer fibrous layer of eye. 

junction of cornea and sclera (fibrous layer of eyeball)

• aka tunic or uvea.  Middle layer of eyeball. 
• Choroid
• Iris
• Ciliary body

network of blood vessels that supply oxygen and nutrients to the tissues of the eye. 

Part of vascular layer sandwiched between the sclera and retina.  Consists mainy of pigments and blood vessels that supply blood to retina. 

Part of eyeball (vascular layer) that makes animal's eyes shine in the dark. 

Colored part of the eye--part of vascular layer.  Contains pupil. 

Opening at center of iris.  Circular.  In nocturnal animals, a slit that can close completely.  Contained in iris of vascular layer of eyeball. 

• A ring-shaped structure located immediatly behind iris in the vascular layer of the eyeball. 
• Consists of tiny muscles that adjust the shape of the lens to allow near or far vision. 

Nervous layer of the eye that contains the actual sensory receptors for vision, rods and cones. 

• Anterior chamber or aqueous humor (between cornea and iris--front),
• posterior chamber or indocorneal angle (between iris and lens),
• vitreous chamber or vitreous humor (inner part of eyeball)

• soft, transparent structure, normally fairly rounded.  Front is in contact with aqueous humor through pupil.  Back is in contact with vitreous humor. 
• Made of layers of microscopic fibers arranged like the layers of an onion.  Elastic and bioconcave (bulges on both sides)

• helps focus a clear image on retina regardless of near or far-ness of object.
• Ciliary body helps--accommodation

When ciliary body helps lens focus a clear image for retina, regardless of where the object is. 

where visual image is formed, sense and converted to nerve impulses that are decoded in the brain to re-form the image in the conscious mind. 

• Main receptor of the eye for low-light vision.  Located in the retina.
• High light sensitivity, low detail, no color.
• Domestic animals have more rods than cones. 

• main receptor of the eye for color and detail.  Located in the retina.
• Low light sensitivity, high detail, high color

Dense accumulation of cones in small depression (called fovea centralis) in center of eye.  Area of clearest vision, only in humans and primates.  Domestic animals don't have one (vision less sharp?)

seen with both eyes.  Predators have more than prey. 

seen with only one eye.  Prey have lots of this. 

• Conjunctiva
• eyelids
• lacrimal apparatus
• eye muscles

thin, transparent membrane that covers the front portion of the eyeball and lines the interior surfaces of the eyelids.  Includes sac where the conjunctiva folds over itself under each eyelid. 

• Inflammation of the conjunctiva.  Most common eye disease. 
• Bacterial/viral infections or chemical/physical irritants cause redness, swelling, ocular discharge and discomfort.  Treated by antibiotic ointment/corticosteroids. 

eyelid

corners of eye-opening. 

modified sebaceous gland between eyelid and conjunctiva

• third eyelid located medially between the eyelids and the eyeball. 
• Gland can prolapse or come out of its position and swell, called cherry eye.  Needs surgical repositioning. 

• overall film that covers eye is made up of three layers:
• oily
• water
• mucus

secretes nutrients and antibodies in watery fluid.  Drains away with nasolactrimal duct and washes away waste.  There is an accessory lacrimal gland of the third eyelid. 

• Lacrimal gland
• Lacrimal puncte
• canaliculus
• lacrimal sac
• nasolacrimal duct

• attach to the sclera.  Small skeletal muscles that hold the eyeballs in place and delicately move them.  6 shared with humans:
• dorsal rectus (straight)
• ventral rectus (straight)
• medial rectus (straight)
• lateral rectus (straight)
• dorsal oblique
• ventral oblique

7th extraocular muscle of many animals.