hoof and claw Flashcards
what is insensitive tissue
specialised epidermal concretion - keratin
what is sensitive tissue
bone, hypodermis
what is most wall horn produced
coronary papillae fire keratin down side of the hoof
what happens once wall horn is made
migrates down foot towards ground sliding along laminae 6-10mm a month, growth occurs for 9-12months
what is the superficial shiny layer of wall horn produced by
proximal perioplic papillae
what is sole horn produced by
solar papillae, produced in the downward direction to make it compact
what is the white line
marking the junction of wall and sole and shows the interface between the sensitive and insensitive tissue
what are hooves, claws and nails
epidermal outgrowths - a keratin sole and wall with a thickened skin pad
what is keratin
protein like collagen and elastin that is physically resistant
what protects the uterus and fetal membranes?
hoof slipper or perinychium
how is horn secreted
secreted by tiny finger like papillae around the top of the hoof wall and sole
describe the papillae structure
each has a dermis core with an epidermal covering
is the epidermis sloughed
no, it is compact
what direction does papillae point in
the direction that it is to grow in
what is stratum externum made by
peroplic papillae
what is stratum medium made by
tubular horn made by corona papillae
what is stratum internum made by
lamellartum, which is insensitive laminae
how do sensitive laminae move
secondary sensitive laminae crawl down the primary sensitive laminae which is done by repeated reforming desmosomes
what are desmosomes
focal point of intracellular attachment
how is venous return achieved in the hoof
hoof lifted > heel recoils axially > ungulate cartilages compress digital cushion > venous return
how is p3 retracted
using axial and abaxial dorsal elastic ligaments
with the wall horn migration where do the laminae attach
underlying sensitive tissue
outline how wall horn allows for weight bearing
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
outline the migration mechanism
longitudinal leaves of dermis/epidermis which interleave with leaves of horn. the innermost layer of insensitive laminae slide past each other.
outline the 3 causes of laminitis
1 endocrine disease e.g. cushings disease 2 sepsis through infection or decrease in gut bacteria 3 supporting limb as a result of lameness
what happens to the hoof when a horse wears its weight
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.
what is ungual cartilage
extensions of p3 palmar processes which are hyaline in juveniles then fibrocartilaginous then ossified as side bones
how does the hoof appear different in the ox
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
describe lameness in the ox
soft surfaces lead to toe overgrowth > p3 rotation > pressure on DDFT
pads in carnivores?
forelimb 1 carpal, 5 digital and 1 metacarpal large. hindlimb 0 tarsal 4 digital and 1 metatarsal
pads in rabbits
no
