Lecture 7: Comparative Histology Of The Hoof

Question 1

Hoof definition

Answer 1

Cornified/keratinized covering of distal end of digit of ungulates

Question 2

Hoof is a modification of

Answer 2

Skin

Question 3

2 types of ungulates

Answer 3

Perisoodactyl/odd toed
Artiodactyl/even toed

Question 4

Perissodactyl includes what animal

Answer 4

Horse

Question 5

Artiodactyls include what animals

Answer 5

Ruminants

Question 6

claw and nails vs hoof

Answer 6

Claw and nails = skin derived appendages
Hoof = skin derived organ

Question 7

Which phalanx is enclosed by claw/nails/hoof

Answer 7

3rd

Question 8

What skin layer gives rise to hoof capsule

Answer 8

Epidermis

Question 9

What skin layer gives rise to corneum

Answer 9

Dermis

Question 10

Which layer/strata of epidermis is keratinized

Answer 10

Stratum corneum

Question 11

What is the periople

Answer 11

Zone of transition from skin to hoof

Question 12

3 main regions of the hoof

Answer 12

Wall
Sole
Frog

Question 13

Corium is continuous with

Answer 13

Dermis of limb skin

Question 14

How many layers is corium

Answer 14

1

Question 15

3 regions of corium (general)

Answer 15

Wall
Sole
Frog

Question 16

3 zones of wall corium

Answer 16

Perioplic
Coronary
Laminar

Question 17

4 layers/strata that constitute the hoof wall (from outer to innermost)

Answer 17

Stratum externum
Outer stratum medium
Inner stratum medium
Stratum internum

Question 18

Peroplic corium is created by which wall strata

Answer 18

Stratum externum

Question 19

Coronary corium is created by which 2 hoof wall strata

Answer 19

Outer stratum medium
Inner stratum medium

Question 20

Laminar corium is created by which hoof wall strata

Answer 20

Stratum internum

Question 21

Which way does hoof grow

Answer 21

Distally

Question 22

Which hoof wall strata grow (3)

Answer 22

Stratum externum
Outer stratum medium
Inner stratum medium

Question 23

Perioplic and coronary regions contain what within corium

Answer 23

Papillae

Question 24

Tubular hoof definition

Answer 24

Hoof wall containing tubular structures

Question 25

Intertubular hoof definition

Answer 25

Compact keratinized tissue embedded within tubular hoof

Question 26

What cells produce/generate the tubular hoof

Answer 26

Differentiating cells of Stratum basale at papillae

Question 27

What cells produce/generate the intertubular hoof

Answer 27

Differentiating cells of Stratum basale at interpapillary region

Question 28

Rhodamine

Answer 28

Red compound that has affinity for keratinized tissue

Question 29

Line of keratinization located

Answer 29

Below papillae

Question 30

Where does non keratinized area of hoof wall exist

Answer 30

Between stem cells and keratinized cells

Question 31

Laminar corium definition

Answer 31

More specialized Papillae takes shape of lamellae

Question 32

Dermal lamellae is modified

Answer 32

Papillae

Question 33

Dermal lamellae interlocks with

Answer 33

Epidermal lamellae

Question 34

Interlocking dermal lamellae with epidermal lamellae: function, importance

Answer 34

Constitutes stratum internum of hoof wall Generates suspensory apparatus - makes attachment of capsule and corium efficient by providing big surface for attachment

Question 35

Laminar corium attaches to (2 things)

Answer 35

Periosteum of PIII Perichondrium of lateral cartilages

Question 36

Secondary lamellae: definition, function

Answer 36

Component of dermal and epidermal lamellae Increase surface are for attachment

Question 37

Stem cells of papillary corium vs secondary epidermal lamellae

Answer 37

Secondary epidermal lamellae - do not differentiate = quiescent

Question 38

Function of sole and frog

Answer 38

Produce more hoof capsule

Question 39

Zona alba aka

Answer 39

White line

Question 40

Zona alba: 2 regions/layers

Answer 40

Outer ring = from stratum internum Inner ring = from internal stratum medium

Question 41

What is the hallmark for the living part of hoof

Answer 41

Zona alba

Question 42

Artiodactyl hoof vs perissodactyl hoof

Answer 42

No frog More extensive digital pad —> reduced sole

Question 43

Specialized structure in arteriodactyl hoof (hint: accessory fingers)

Answer 43

Accessory hooves = “dewclaws”

Question 44

Are all the corium regions present in artiodactyl hooves

Answer 44

Yes

Question 45

Do epidermal and dermal lamellae of arteriodactyl hooves have secondary lamellae

Answer 45

No

Question 46

Digital pad corium replaces what and then is continuous with what in arteriodactyl hoof

Answer 46

Frog corium Sole corium

Question 47

Corium attaches to what 3 structures

Answer 47

3rd phalanx Lateral cartilages Digital cushion

Question 48

Laminitis: definition, effects, corrected by

Answer 48

Inflammation of dermal lamellae Leads to detachment of 3rd phalanx Heterogenous distribution of blood flow Corrected by hoof trimming