hoof and claw

Question 1

what is insensitive tissue

Answer 1

specialised epidermal concretion - keratin

Question 2

what is sensitive tissue

Answer 2

bone, hypodermis

Question 3

what is most wall horn produced

Answer 3

coronary papillae fire keratin down side of the hoof

Question 4

what happens once wall horn is made

Answer 4

migrates down foot towards ground sliding along laminae 6-10mm a month, growth occurs for 9-12months

Question 5

what is the superficial shiny layer of wall horn produced by

Answer 5

proximal perioplic papillae

Question 6

what is sole horn produced by

Answer 6

solar papillae, produced in the downward direction to make it compact

Question 7

what is the white line

Answer 7

marking the junction of wall and sole and shows the interface between the sensitive and insensitive tissue

Question 8

what are hooves, claws and nails

Answer 8

epidermal outgrowths - a keratin sole and wall with a thickened skin pad

Question 9

what is keratin

Answer 9

protein like collagen and elastin that is physically resistant

Question 10

what protects the uterus and fetal membranes?

Answer 10

hoof slipper or perinychium

Question 11

how is horn secreted

Answer 11

secreted by tiny finger like papillae around the top of the hoof wall and sole

Question 12

describe the papillae structure

Answer 12

each has a dermis core with an epidermal covering

Question 13

is the epidermis sloughed

Answer 13

no, it is compact

Question 14

what direction does papillae point in

Answer 14

the direction that it is to grow in

Question 15

what is stratum externum made by

Answer 15

peroplic papillae

Question 16

what is stratum medium made by

Answer 16

tubular horn made by corona papillae

Question 17

what is stratum internum made by

Answer 17

lamellartum, which is insensitive laminae

Question 18

how do sensitive laminae move

Answer 18

secondary sensitive laminae crawl down the primary sensitive laminae which is done by repeated reforming desmosomes

Question 19

what are desmosomes

Answer 19

focal point of intracellular attachment

Question 20

how is venous return achieved in the hoof

Answer 20

hoof lifted > heel recoils axially > ungulate cartilages compress digital cushion > venous return

Question 21

how is p3 retracted

Answer 21

using axial and abaxial dorsal elastic ligaments

Question 22

with the wall horn migration where do the laminae attach

Answer 22

underlying sensitive tissue

Question 23

outline how wall horn allows for weight bearing

Answer 23

1 the horn migrates down to the ground where it is worn away 2 suspend the weight of the horse from the inner surface of the hoof wall

Question 24

outline the migration mechanism

Answer 24

longitudinal leaves of dermis/epidermis which interleave with leaves of horn. the innermost layer of insensitive laminae slide past each other.

Question 25

outline the 3 causes of laminitis

Answer 25

1 endocrine disease e.g. cushings disease 2 sepsis through infection or decrease in gut bacteria 3 supporting limb as a result of lameness

Question 26

what happens to the hoof when a horse wears its weight

Answer 26

heels splay abaxially which stores elastic potential energy, the frog allows the sole to widen. as the heel rebounds axially there is pressure on the ungual cartilage.

Question 27

what is ungual cartilage

Answer 27

extensions of p3 palmar processes which are hyaline in juveniles then fibrocartilaginous then ossified as side bones

Question 28

how does the hoof appear different in the ox

Answer 28

sole and heel bulb both are weight bearing. no digital cushion. hyperdermis is thin but wall is thicker abaxially. lateral claw is bigger than medial claw. coronary dermis more extensive. no secondary laminae

Question 29

describe lameness in the ox

Answer 29

soft surfaces lead to toe overgrowth > p3 rotation > pressure on DDFT

Question 30

pads in carnivores?

Answer 30

forelimb 1 carpal, 5 digital and 1 metacarpal large. hindlimb 0 tarsal 4 digital and 1 metatarsal

Question 31

pads in rabbits

Answer 31

no