Lecture 7: Comparative Histology Of The Hoof Flashcards
Hoof definition
Cornified/keratinized covering of distal end of digit of ungulates
Hoof is a modification of
Skin
2 types of ungulates
Perisoodactyl/odd toed
Artiodactyl/even toed
Perissodactyl includes what animal
Horse
Artiodactyls include what animals
Ruminants
claw and nails vs hoof
Claw and nails = skin derived appendages
Hoof = skin derived organ
Which phalanx is enclosed by claw/nails/hoof
3rd
What skin layer gives rise to hoof capsule
Epidermis
What skin layer gives rise to corneum
Dermis
Which layer/strata of epidermis is keratinized
Stratum corneum
What is the periople
Zone of transition from skin to hoof
3 main regions of the hoof
Wall
Sole
Frog
Corium is continuous with
Dermis of limb skin
How many layers is corium
1
3 regions of corium (general)
Wall
Sole
Frog
3 zones of wall corium
Perioplic
Coronary
Laminar
4 layers/strata that constitute the hoof wall (from outer to innermost)
Stratum externum
Outer stratum medium
Inner stratum medium
Stratum internum
Peroplic corium is created by which wall strata
Stratum externum
Coronary corium is created by which 2 hoof wall strata
Outer stratum medium
Inner stratum medium
Laminar corium is created by which hoof wall strata
Stratum internum
Which way does hoof grow
Distally
Which hoof wall strata grow (3)
Stratum externum
Outer stratum medium
Inner stratum medium
Perioplic and coronary regions contain what within corium
Papillae
Tubular hoof definition
Hoof wall containing tubular structures
Intertubular hoof definition
Compact keratinized tissue embedded within tubular hoof
What cells produce/generate the tubular hoof
Differentiating cells of Stratum basale at papillae
What cells produce/generate the intertubular hoof
Differentiating cells of Stratum basale at interpapillary region
Rhodamine
Red compound that has affinity for keratinized tissue
Line of keratinization located
Below papillae
Where does non keratinized area of hoof wall exist
Between stem cells and keratinized cells
Laminar corium definition
More specialized
Papillae takes shape of lamellae
Dermal lamellae is modified
Papillae
Dermal lamellae interlocks with
Epidermal lamellae
Interlocking dermal lamellae with epidermal lamellae: function, importance
Constitutes stratum internum of hoof wall
Generates suspensory apparatus - makes attachment of capsule and corium efficient by providing big surface for attachment
Laminar corium attaches to (2 things)
Periosteum of PIII
Perichondrium of lateral cartilages
Secondary lamellae: definition, function
Component of dermal and epidermal lamellae
Increase surface are for attachment
Stem cells of papillary corium vs secondary epidermal lamellae
Secondary epidermal lamellae - do not differentiate = quiescent
Function of sole and frog
Produce more hoof capsule
Zona alba aka
White line
Zona alba: 2 regions/layers
Outer ring = from stratum internum
Inner ring = from internal stratum medium
What is the hallmark for the living part of hoof
Zona alba
Artiodactyl hoof vs perissodactyl hoof
No frog
More extensive digital pad —> reduced sole
Specialized structure in arteriodactyl hoof (hint: accessory fingers)
Accessory hooves = “dewclaws”
Are all the corium regions present in artiodactyl hooves
Yes
Do epidermal and dermal lamellae of arteriodactyl hooves have secondary lamellae
No
Digital pad corium replaces what and then is continuous with what in arteriodactyl hoof
Frog corium
Sole corium
Corium attaches to what 3 structures
3rd phalanx
Lateral cartilages
Digital cushion
Laminitis: definition, effects, corrected by
Inflammation of dermal lamellae
Leads to detachment of 3rd phalanx
Heterogenous distribution of blood flow
Corrected by hoof trimming
