Lecture 6 Hoof Flashcards by jillian Bastidas

What are the four layers of epidermis

stratum corneum (keratin)
stratum granulosum
stratum spinosum
stratum basale (germinal layer)

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the epidermis is ___

avascular

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The dermis or ___ is ___

corium

well vascularized and innervated

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Three layers of skin

epidermis
dermis
subcutaneous

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papillea may be merged into linear structures called

laminae

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three parts of the horn

insensitive, keratinized, horn proper (stratum corneum)

supportive dermis

sensitive bone core

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two parts of horn proper

tubular keratinized tissue

intertubular keratinized tissue

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Horns can be filed because it does not damage what part of the horn?

the living core

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Dehorning is considered a surgical procedure because it

removes the living core

frontal sinus extends into the bony core

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how is a horn different from antlers

Horns: 
permanent
seen in both sexes
specialized keratinized structure
bovidae family
internal blood supply
usually not branched

Antlers:
shed yearly
only in males
bone
cervidae family (deer)
external blood supply (velvet)
branched

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another name for nail, claw or hoof

ungual

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fingernails are

keratinized layer of epidermis that forms a similar structure to what is under it

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walking on flat foot

plantigrade

humans

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walking on digits

digitigrade

dogs

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Walking on one digit

unguligrade

horse

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what is the part of P3 that allows the nail to “slide”

sensitive lamellar dermis

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germinal epidermis is at what end of P3

base

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what is the sole of a claw

softer flaky, non tubular keratinized material elaborated from the sole epidermis, which is supported by sole dermis (corium)

distal part of claw that is sealed off

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horse

junction of the skin and hoof

coronary band or coronet

cuticle

horse:

what is the wall of the hoof

hard structure (25% water) made up of tubular and intertubular keratinized tissue, often pigmented

toe, quarters, heel and bars

the wall of the hoof is divided into

toe
quarters
heel
bars

horse:

sole in the hoof

softer than wall (33% water), located at ground surface of hoof (but normally does not make ground contact) also made of tubular and intertubular keratinized tissue

Horse

Frog

triangular structure which makes contract with ground (50% water) it is analogous to the digital pad of the dog. it consist only of tubular keratinized tissue

Horse

white line

a light layer at the junction of the wall and the sole as seen from the solar surface

three layers of hoof wall

external middle internal

describe external layer of hoof wall

stratum externum ring of soft, non pigmented tubular keratinized tissue which forms a the junction of the skin and and hoof wall (similar to human cuticle-coronary band ) extends less than an inch distally over the middle layer(stratum medium) except at the bulbs of the heels where it is more extensive

describe middle layer of hoof wall

stratum medium | majority of the hoof wall thickness and is composed of hard tubular and intertubular keratinized tissue

describe internal layer of hoof wall

stratum internum insensitive laminae most internal layer of the hoof wall, layer of parallel sheets of unpigmented keratinized tissue that interdigitate with the sensitive laminae (dermis or corium which is attached to PIII) as the hoof wall grows distally (from the coronary band region), the insensitive laminae (internal layer) slide between and there past the sensitive, stationary laminae attached to PIII

hoof wall

source is the germinal apidermis, located at the coronary band grows 1 cm/ month

human finger nail grows

0.5 mm/ week

attachment tissue

dermis (corium) with its epithelial (thin) coverings 1. intimately attached to the periosteum of P111 2. vascular and innervated (therefore sensitive) 3. covering epithelium may be active or inactive (normal state) depending on location and pathologic condition

laminar dermis of attachment tissues

covers the dorsal surface of PIII has a thin covering of epidermal cells, which tear off and therefore allow the hoof to grow past it. it normally produced only a small amount of keratinized tissue

attachment tissue: solar surface

significant amount of keratinized tissue proliferation, which wears off or is trimmed off by the farrier

person who shoes a horse

farrier

4 major zones of epithelial growth in hoof

coronary laminar sole frog

describe coronary zone of hoof

papillate, actively growing, where the entire hoof wall grows from located in the region of the coronary band, growth is directed distally (1 cm/ month)

describe laminar zone of hoof

sensitive laminae does not normal produce any significant amount of keratinized tissue. firmly attached to the dorsal aspect of P111

describe sole zone of hoof

ob the solar surface of P111

describe frog zone of hoof

overlies the digital cushion and is located between the cartilages of the hoof

epidermis and dermis can be in what shapes

smooth papillae linear (laminae)

toe and white line