Lecture 11 - Hoof Flashcards
What are perissodactlys?
odd-toed ungulates
What are artiodactlys?
even-toed ungulates
What animal is an odd-toed?
Equine
What animal is an even-toed?
Bovine, carpine, swine, and ovine
What is the hoof a form of?
Highly specialized skin
How is the hoof formed?
Cornification of the entire integument at distal end of the limb
Why have these animals adapted hooves?
Due to being weight bearing on one or two digits, hoof made to handle force
What does the hoof capsule equate too?
Epidermis
What does the corium equate to?
Dermis
What is the corium?
Modified dermis, continuous with dermis skin
What is the function of the corium?
Provide physical and nutritional support to the hoof capsule
What are the layers in the hoof wall?
Stratum externum, outer s. medium, inner s. medium, s. internum
What is each wall paired with?
A corium
What wall layer does the perioplic corium provide for?
S. externum
What wall layer does the coronary corium provide for?
Medium layers
What wall layer does the laminar corium provide for?
S. internum
What coriums are papillary coriums?
perioplic and coronary
What do papillary coriums do?
Associate with regions that produce new hoof
Where is the s. basal located? (what regions?)
Papillae and inter-papillary
What do s. basal at the papillae region produce?
Tubular hoof
What do s. basal at the inter-papillary regions produce?
intertubular hoof
What can keratin be stained with to see?
Rhomadine + ve
What stratum layer is keratinized?
s. corneum
What does the laminar corium interlock with?
epidermal lamellae
Where does this occur?
hoof capsule
What is the function of the interlocking of the laminar corium and the epi. lamellae?
suspend distal phalanx
What two other layers does the laminar corium attach to?
Periosteum of PIII
Perichondrium of lateral cartilages
What is another name for dermal lamellae?
Modified papillae
What is the function of secondary lamella?
increase surface area for attachment
What two types of secondary lamellae are there?
dermal and epidermal
What type of corium is the sole and frog?
papillary corium
What is the papillary corium associated with (function-wise)?
Regions responsible for distal hoof growth
Where do the coriums attach?
Periosteum of PIII and capsule of digital cushion
What is the zona alba?
point where papillar corium of sole replace laminar corium and different wall strata
What is another name for the papillary corium?
terminal papillae
What are the layers of the zona alba?
S. internum and I.S. medium
Which layer of zona alba is keritanized?
I.S. Medium
What layer represents the white line at the zona alba?
I.S. medium, deepest non-alive layer
What layers do horse shoe nails go through?
I.S. medium, O.S. medium, and S. Externum
In what direction is hoof growth?
Downwards to replace hoof lost via floor contact
What causes the downward hoof growth?
in the papillary corium the s. basal makes new hoof and pushes it down ward
What are the lamellar remodeling enzymes?
MMP and TIMP
What does MMP do?
digest laminin and collagen
What does TIMP do?
inhibit MMP
What is different about an artiodactly hoof?
No frog More of a foot pad Reduced sole No bars Wall extends axially
What is different about the lamellae in the epidermal and dermal regions?
no secondary lamellae
What does the lack of secondary lamellae mean?
Not as strong interlocking, weaker
What replaces the frog corium in artiodactyl?
Footpad corium
What is the footpad corium continuous with?
Sole corium
What is the digital cushion made of?
Fat and fibroelastic tissue
What extra appendage do artiodactyls have?
Dewclaws, mini-hooves of accessory fingers
What “apparatus” are ungulates highly dependent on in their hooves, that can be the cause of laminitis?
Lamellar distal phalangeal suspensory apparatus
