Integument and related structures Flashcards

Question

Chestnuts are located

Answer 1

Medial on each leg at carpus and tarsus

Answer 2

Buried in caudal hairs of fetlock

Answer 3

Dorsum of nose in cats, pigs, sheep, dogs Composed of polygonal plates in dogs

Answer 4

Extends to lips Muzzle of cows Hairless in cattle

Answer 5

Usually pigmented Aglandular in SA, glandular in sheep and cattle

Answer 6

Sick cows may stop licking their nose and drool clear mucous from their nose Not necessarily a sign of respiratory disease

Answer 7

Infoldings of skin Contain fine hair, sebaceous and oil glands Three locations Infraorbital Interdigital Inguinal Fatty yellow secretion dries and sticks to skin

Answer 8

Pain Itching (licking/chewing/scratching) (pruritus) Reddening Immobility (Loss of function) Alopecia (loss of hair) Thickening (lichenification) Wrinkling Pigmentation (melanosis) Swelling: Edema Heat

Answer 9

Maintenance of body temperature Traps air Dark colors absorb light Protection via camouflage

Answer 10

Shaft: part of hair visible above skin Root: part of hair below skin Hair follicle: invagination of the epidermis into dermis or hypodermis

Answer 11

Medulla: core of the hair Cortex: hard keratin – thickest layer Cuticle: thin layer of cells on the surface of the hair arranged in shingle-like layers

Answer 12

deepest part of hair follicle – expanded, knob-like, hollow area

Answer 13

mound of dermal cells at the base of the bulb

Answer 14

rapidly dividing epithelial cells covering the papilla Nourished by vessels below As cells divide, they push older cells up become keratinized & die become hair

Answer 15

Web of sensory nerve endings around the root Makes hair sensitive to touch

Answer 16

Multiple hair strands, each with its own follicle, can emerge from a single pore Three follicles group to emerge from same epidermal fold in dogs Can contain a mixture of primary and secondary follicles (see later)

Answer 17

Anagen: growth Catagen: transition Telogen: resting

Answer 18

During telogen hair bulb separates from the dermis Hair falls out or is pushed out when new hair growth starts ‘Shedding’ the coat is technically called telogen effluvium Can occur seasonally (photoperiod), due to disease, or through hormonal changes (such as after parturition in bitches (blowing the coat)

Answer 19

shedding the coat

Answer 20

Pigment in cortex and medulla of hair strand Melanin produced in base of hair follicle Melanin transferred to cortical and medullary cells of hair strand Different colors Quantity of melanin Type of melanin Orange type Black/brown type No melanin = white Melanin production decreases with age

Answer 21

guard hairs Straight or arched; thicker and longer than secondary hairs

Answer 22

Softer and shorter than primary hairs Predominant type of hair in wool type coats Wool breeds have many secondary hair follicles

Answer 23

Long primary guard hair Surrounded by soft wool hairs

Answer 24

Wool breeds have many secondary hair follicles Secondary hair is often waxy (lanolin) Makes it waterproof Used in skin ointments

Answer 25

Small, smooth muscle Attached to each hair follicle Innervated by sympathetic nervous system Contraction pulls the hair erect

Answer 26

Sudoriferous Glands Produce watery, transparent liquid Help cool body through evaporation Found over entire body Only horse produces profuse sweat

Answer 27

Eccrine: empty onto surface of skin Apocrine: empty into hair follicles

Answer 28

Located in dermis Simple or complex alveolar structures Duct empties into hair follicle or directly onto skin Lips, labia vulvae, penis, prepuce, anus, eyelid, ear canal (ear wax) Produce sebum Oily, lipid substance Manufactured and stored by sebaceous glands Sebum forced through duct into hair follicle

Answer 29

Sebum coats base of hair and surrounding skin Traps moisture Keeps skin and hair soft, pliant, waterproof Reduces risk of infection Sheep sebum is called lanolin

Answer 30

Secretion of sebum is hormone sensitive Increased production of sebum at puberty, sebum binds dead skin cells, blocks duct opening. Ducts swell and may rupture – releases bacteria into epidermis and dermis,inflammation and abscess

Answer 31

Oval region at dorsal base of tails of dogs and cats, contain: Large sebaceous glands Coarse, oily hairs May have different color Assist animals in identification of one another More noticeable in males Called Stud Tail in cats Also found on chin and lips of cats May develop into cysts

Answer 32

Reservoir for malodorous secretions, similar to those from musk glands Lined with sebaceous and apocrine glands Contents are expressed at: Defecation: marks territory When animal is frightened Location in cats and dogs Connected by single small duct to lateral margin of anus Can become blocked / infected

Answer 33

May become impacted or infected – ‘scooting’ Pain and discomfort on sitting Licking and biting at anal area Painful defecation If severe, may swell and rupture and drain pus May be a sign of allergies

Answer 34

Express with digital pressure Keep your mouth closed Flush with catheter and warm water +/- disinfecting soap May surgically remove

Answer 35

Ruminants have 4 hooves per foot – each covers a digit, but only 2 digits (3rd and 4th) per foot are weight- bearing

Answer 36

Weight bearing hooves are called medial and lateral claw

Answer 37

Is equivalent to our fingernail Divided into toe, quarters (medial and lateral), and heel regions Thickest at the toe and thinnest at the heel. Hoof wall cross sections Have tiny vertical lines running from coronary band to ground - called horn tubes May have horizontal rings or ridges around hoof – represent different periods of growth due to changes in nutrition or founder Grows continuously from the (corium of the) coronary band down Hoof walls are flexible and expand as weight is born on hoof

Answer 38

like a modified dermis The underlying tissue which is sensitive and vascular. Firmly attached to periosteum of distal phalanx – links bone to hoof wall Lots of blood vessels and nerves Divided into coronary corium (beneath coronary band), perioplic corium (beneath periople), laminar (wall) corium, sole corium (on the sole of the foot), and corium of the frog (above/behind the frog)

Answer 39

Narrow region approximately 2-3 cm at proximal border of hoof Epidermal cells here produce the external layer of the hoof wall Corresponds to the cuticle of the fingernail Waterproof and pigmented

Answer 40

Wider band distal to periople Cells here produce the middle layer of the hoof wall The hoof grows from the coronary band downward Growth of the hoof is continuous Without trimming the hoof can become so long that it curls upward

Answer 41

Hoof and corium form laminae, which interlock Connect the hoof wall to the corium, which is bound to P3 Laminae permit hoof wall to grow distally by sliding over each other Dermal laminae are sensitive

Answer 42

Bottom (plantar or palmar) surface of the hoof Protects from injury Concave – not primary weight-bearing area Improves foothold No nerves or vessels superficially White line – indicates junction of the sole and hoof wall

Answer 43

Triangular shaped structure with a central sulcus or cleft Below the frog is a thick pad of fat and fibrous tissue, called the digital cushion Functions Cushion at the heel of the foot Reduces slipping Helps to mechanically pump blood back up the leg from the corium during weight-bearing (see below) Remember to firmly pick out the sulci of the frog when you clean a horse’s foot

Answer 44

Shoeing a horse prevents excessive expansion of the hoof when the animal carries weight Also improves traction and creates a barrier between the ground and hoof – protects from injuries Usually combined with trimming

Answer 45

Frog and digital cushion are flattened and widened during weight-bearing This puts pressure on the walls and bars and collateral cartilages causing the walls to spread at the heels Pressure forces blood out of the vascular bed of the foot Since the blood is forced out against some resistance, this provides additional absorption of concussion

Answer 46

Lateral or collateral cartilages are a pair of cartilage structures attached to the angles of P3 and extending into the area of the heel proximal to the coronary band of the hoof

Answer 47

Distal part of the middle phalanx, distal sesamoid bone – “navicular”, and the distal phalanx – “coffin bone” The distal (3rd) phalanx has layers of sensitive laminar corium which interdigitate with the laminae of the hoof

Answer 48

Inflammation of the laminae attaching hoof wall to corium Laminae swells Swelling is trapped inside the wall of the hoof Inhibits blood flow to corium due to compression Corium may degenerate Attachment between wall and corium is lost Pedal bone can rotate or sink within the hoof Puts pressure on sole, may perforate sole

Answer 49

Overload Inflammatory Metabolic diseases

Answer 50

reduced weight bearing on a limb (trauma or surgery) causes excessive weight bearing in other limbs

Answer 51

A major cause is dietary Sudden increase in the amount of grain (intentionally or accidentally) or rapidly growing fresh spring grass ingested. Grain is full of starch and some will reach the large intestine. Grass is full of fructose polymers which cannot be digested in SI and pass intact to LI As a result there is bacterial overgrowth and fermentation in the large intestine. Toxins are produced. These are absorbed and produce inflammation of the hoof wall

Answer 52

Insulin dysregulation, abnormal fat deposition, difficulty losing weight. “Cresty” neck horses and ponies

Answer 53

Pituitary pars intermedia dysfunction (PPID) Equine Cushings Cortisol excess causes delayed shedding (results in longhair coats), PU/PD, insulin dysregulation

Answer 54

Treatment – pain relief and anti-inflammatory meds Ice – prevents breakdown of laminae Some changes can be corrected or improved with corrective shoeing and trimming, feed, and management (takes months) Euthanasia if rotation has occurred

Answer 55

Laminitis is extremely painful Usually front feet are affected (can be all 4) Horses stand with front feet out and hind limbs under body If all 4 feet affected, all feet are tucked together Horse may lay down a lot and be unwilling to stand Hooves feel warm with increased digital pulses Sole may sink (flatten) P3 may poke through sole Hoof wall develops ridges and curls up at toe

Answer 56

Limit high CHO feeds Especially ponies in Spring Often occurs after sudden introduction to lush pasture grazing or high CHO foods like grain, molasses, and corn Severe illness (retained placenta with metritis) can also be complicated by laminitis Monitor feet carefully and treat at first signs

Answer 57

Vertical cracks in hoof Named for region of occurrence - toe, heel, quarter cracks Cause If begin at solar border result of improper or no trimming If begin at coronary band results from defect in hoof formation Excessive drying of hoof predisposes to the condition

Answer 58

Degenerative condition of the frog Associated with filth and various micro-organisms. Characterized by black, necrotic, foul smelling material in the affected area

Answer 59

Foot is narrower than normal May be caused by lack of frog pressure and often occurs in horses improperly shod Front more commonly affected than back and can be severe enough to cause lameness known as hoofbound Contracted heels the heels of affected horses are drawn in, the bars are almost parallel and the frog is much reduced in size. Also called contracted hoof or contracted foot.

Answer 60

Chronic degenerative condition of navicular bone Seen in older horses Primarily a disease of the forefeet Trauma of high impact weight bearing (racing) and defective shoeing are contributory factors Often begins with loss of cartilage and inflammation of the bursa between the navicular bone and the deep digital flexor tendon Navicular disease is a common cause of “heel pain” lameness in horses

Answer 61

Proliferative inflammation of interdigital space, coronary region and P3. Several micro-organisms cause foot rot Signs: Foul smell, redness, swelling, redness, discharge from damaged interdigital skin Very responsive to antibiotics

Answer 62

Infection of the heel bulb and interdigital skin Rarely lame Treated with topical disinfectants such as coppertox. Wear gloves!

Answer 63

Proliferation of tissue of interdigital cleft Often associated with foot rot and interdigital dermatitis Mass of connective tissue projecting down and between claws Walking becomes painful as corn increases in size

Answer 64

usually animal is suffering from overgrown hooves resulting in abnormal weight bearing, may also be laminitic Incidence increases during dry weather which causes hoof wall to become hard and lose its elasticity

Answer 65

usually occur in mature dairy cattle following attack of laminitis Usually all 8 claws are affected

Answer 66

Most foot lameness of cattle is directly or indirectly related to laminitis Major cause - ingestion of excessive amounts of grain. Only mildly painful in cattle. The integrity of the lamina and hoof wall and sole are all compromised when laminitis occurs Overgrown and malformed hooves result, haemorrhage in the sole, possibly necrotic toe lesions

Answer 67

Boney outgrowth with epidermal covering Similar to hoof - keratin tubules bound to periosteum of underlying bony core by a corium Starts as an epithelial horn bud. Grows out as a solid structure that becomes hollowed out by about 6 months of age Adult animals have hollow horn that communicates with the frontal sinus Male and female animals may have horns Pronghorn antelope are only species to shed horn annually – rest are permanent and grow continuously through life Polled = no horns in a species that was historically horned, though can have remnants

Answer 68

Tend to be only in males Shed annually Bony growth that is nourished by the velvet on the outside Once grown, a connective tissue ring forms like a tourniquet around the base of the antler to cause velvet slough Antler hardens Late fall/winter the bony base connecting antler to skull weakens and antler falls off

Answer 69

PAINFUL!!! Many methods used to get animals to cooperate Local anesthetic blocks Tourniquet Restraint (physical, chemical)