Lecture 6 Hoof Flashcards
What are the four layers of epidermis
stratum corneum (keratin)
stratum granulosum
stratum spinosum
stratum basale (germinal layer)
the epidermis is ___
avascular
The dermis or ___ is ___
corium
well vascularized and innervated
Three layers of skin
epidermis
dermis
subcutaneous
papillea may be merged into linear structures called
laminae
three parts of the horn
insensitive, keratinized, horn proper (stratum corneum)
supportive dermis
sensitive bone core
two parts of horn proper
tubular keratinized tissue
intertubular keratinized tissue
Horns can be filed because it does not damage what part of the horn?
the living core
Dehorning is considered a surgical procedure because it
removes the living core
frontal sinus extends into the bony core
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
another name for nail, claw or hoof
ungual
fingernails are
keratinized layer of epidermis that forms a similar structure to what is under it
walking on flat foot
plantigrade
humans
walking on digits
digitigrade
dogs
Walking on one digit
unguligrade
horse
what is the part of P3 that allows the nail to “slide”
sensitive lamellar dermis
germinal epidermis is at what end of P3
base
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
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
- intimately attached to the periosteum of P111
- vascular and innervated (therefore sensitive)
- 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
toe and white line
quarter and apex of frog
quarter and apex of frog
heel and wall
heel and wall
bulbs and sole
bulbs and sole
central sulcus of frog + collateral sulcus of frog
central sulcus of frog + collateral sulcus of frog
angle of wall and bars
angle of wall and bars
