footpads, claws, hooves, horns and antlers Flashcards
week 2 lect 3 Basu (108 cards)
1
Q
what anchors the subcutis to the skeleton?
A
ligaments
2
Q
what sweat glands do the footpads have?
A
eccrine sweat glands
3
Q
what do the sweat glands in the footpads do?
A
gives footpads increased grip - the moisture increases friction
4
Q
link between nails, claws and hooves?
A
homologous structures –> keratin
5
Q
what is horn?
A
highly keratinised epidermis
6
Q
how does horn grow?
A
grows from the epidermis at their base and gradually slides distally
7
Q
transverse ridges on hoof
A
parallel with the ground
8
Q
epidermal structure?
A
nail, hoof, claw
9
Q
ridges in nails?
A
interdigitations of laminae
10
Q
quick (pink bit) of the claw
A
the dermis - do not cut here when trimming nails
11
Q
what keeps the claws retracted in cats?
A
elastic dorsal elastic ligaments
12
Q
which is the only weight-bearing digit in horses?
A
digit III
13
Q
What are the five parts of the dermis of the hoof?
A
perioplic
coronary
lamellar
solar
frog
14
Q
in a hoof - what is the subcutis confined to?
A
the coronary cushion
the digital cushion
15
Q
dermal segment supports the…
A
epidermal segment
16
Q
what are the three layers of the hoof wall?
A
external layer - stratum externum
middle layer - stratum medium
internal layer - stratum internum
17
Q
which is the thickest layer of the hoof?
A
the middle layer - stratum medium
18
Q
what are cervids?
A
deer
19
Q
what are horns seen in?
A
BOVIDS - cattle, sheep, antelope
20
Q
whereas antlers are seen in?
A
CERVIDS - deer
21
Q
where do antlers grow from?
A
they grow out from an attachment on the skull - the pedicle
22
Q
where do horns grown from?
A
horn bud starts out in the subcutis and LATER fuses to the skull
23
Q
horn fracture complication?
A
infection in the sinuses as the horn has sinuses that goes directly into frontal bone of skull
24
Q
what does the number of digital pads represent?
A
the number of digits
25
what are footpads named after?
the underlying region e.g. metatarsal pad, carpal pad
26
digital footpads in dogs, cats etc. is homologous with what in ruminants and pigs?
bulb
27
digital footpads in dogs, cats etc. is homologous with what in horses?
frog
28
what other pads do horses have?
metacarpal/metatarsal pads and carpal/tarsal pads
29
what are metacarpal/metatarsal footpads called?
ergots
30
what are carpal/tarsal footpads called?
chestnuts
31
what are foot pads? describe their structure:
thick epidermis
thick subcutis
32
describe the subcutis found in footpads:
adipose tissue partitioned by collagen and elastic fibres
33
what do footpads function as?
shock absorbers
34
what are footpads known as in hooved animals:
digital cushions
35
describe footpads in terms of hair:
hairless
36
what characteristic of a foot pad protects the sensitive dermis from damage?
the thickly cornified epidermis (think - corneocytes)
37
footpads have an additional epidermal layer - name? and describe visibility:
stratum lucidum
sometimes visible
38
nails in primates - what are the homologous structures in carnivores/birds and ungulates?
claws in carnivores/birds
hooves in ungulates
39
3 functions of nails, claws and hooves:
protects the distal digit, scratching/digging etc, defence/hunting
40
what are the 3 similar components of the distal joints of primates, ungulates, carnivores, birds?
wall, sole, footpad
41
Describe the whereabouts of the wall, sole, footpad on humans:
wall - outer of the nail, and tip of the nail
sole - under the nail, where the footpad and wall meet
footpad - spongy part of finger (fingertip)
42
what is the footpad of a horse also known as?
the frog
43
describe the wall, sole and footpad whereabouts on a horse:
wall is the outer part enclosing the rest of the hoof
sole is underneath and connects the footpad to the wall.
the footpad is the base of the hoof (descriptive wise)
44
describe the epidermis of the nails/claws/hooves:
highly keratinised epidermis
45
what is highly keratinised epidermis called?
horn
46
how do nails/claws/hooves grow?
from epidermis at their base and gradually slide distally (as an animal is standing, growing towards ground)
47
What causes the ridges to appear in nails/claws/hooves? (look at your fingernail, you can see lines)
periods of disturbed growth - resulting in transverse ridges (which are parallel with the base/ground
48
what kind of structure is a nail/claw/hoof?
an epidermal structure
49
what anchors the nail/claw/hoof to the underlying dermis?
interdigitations of laminae
50
what is not present at the epidermal-dermal junction of a nail/claw/hoof?
there is no subcutis
51
what is the distal phalanx?
the bone of the finger/toe
52
what is the dermis closely adhered to?
the periosteum of distal phalanx (go over, slider 18 01/10/24)
THERE IS NO SUBCUTIS HERE
53
what is the 'quick'?
the dermis - the pink bit of the nail
54
when trimming nails, what would cutting the 'quick' cause?
pain, and it would bleed
55
where is the muscle mass concentrated in the hooves of a horse?
proximally
56
describe the motion of a horses hoof:
protraction and retraction, literally just forwards and backwards
57
what does cursorial mean?
one that is adapted specifically to run
58
describe the venous return of blood for the hoof:
it is poor
59
if a horse damages one of its hooves, what happens?
it will really struggle, as a quarter of its bodyweight is supposed to be distributed through that hoof
60
what does squashing of digital cushion aid?
aids the blood return with each step - to help with the poor venous return of blood
61
What is the dermis of the hoof called?
the corium
62
what does the epidermal segment correspond to?
the dermal segment
63
what part of the dermis corresponds to the external layer of the hoof wall?
perioplic (dermal segment)
64
what part of the dermis corresponds to the middle layer of the hoof wall?
coronary (dermal segment)
65
what part of the dermis corresponds to the internal layer of the hoof wall?
laminar
66
what part of the dermis corresponds to the sole (epidermal segment)?
sole (dermal segment)
67
what part of the dermis corresponds to the frog (epidermal segment)?
frog (dermal segment)
68
what is the laminar (segment of dermis of hoof wall) also known as?
dermal laminae
69
what is the internal layer of the hoof wall (the epidermal segment) also known as?
epidermal laminae
70
describe the external layer of the hoof wall:
thin, glossy, produced by perioplic dermis
71
describe the middle layer of the hoof wall:
thickest layer of hoof wall, partially pigmented, produced by coronary dermis
72
describe the internal layer of the hoof wall:
produced by the lamellar dermis
73
where are there no blood vessels or nerves in the hoof wall and what does this mean?
none in the epidermis, all blood and nerve impulses come via diffusion from the dermis
74
describe horns strength: (in terms of the hoof wall)
strong with some elasticity
75
what is the travel time for the horn to go from top to bottom of the hoof? AT THE TOE, IN ADULT
9-12 months
76
what is the travel time for the horn to go from top to bottom of the hoof? AT HEEL
4-6 months
77
what have antlers?
cervids (deer)
78
what are ossicones found in?
giraffids
79
what are giraffids? give 2 examples:
giraffes, okapis
80
what are pronghorns found in?
antilocaprids
81
what are antlers and horns initially formed from?
from bony core which is covered by integument
82
where are antlers and horns located?
on the frontal bone of the skull
83
when growing - antlers are covered in?
well-vascularised skin
(in velvet)
84
when the antlers have finished growing, what happens and what is this stage called?
the blood supply to the skin is cut off and the velvet is shed
(in tatters)
85
what is mature antler?
exposed living bone
86
describe the cycle of antlers:
they are usually shed (cast) and re-grown every year, sometimes antlers grow bigger and more branched every year
87
what is the cycle of antlers related to?
sex hormones
88
Describe the growth of horns:
horn bud (starts off as soft tissue) starts out in the subcutis and later fuses to the skull
89
briefly describe the structure of the horn:
horns have a scabbard-like keratin covering a bony core
90
describe branching of horns:
not branched
91
do horns shed?
no
92
why can horns show rings/ridges?
horns grow with age
93
why do people sometimes choose to dehorn cattle?
reduce injury to people/other livestock
reduce space required (housing/feeding)
94
why is it better to 'disbud' as a calf?
horn bud starts out 'floating' in integument and LATER attaches to frontal bone
(better to do younger to reduced risk of infection of sinus as after 6 months, the frontal sinus starts extending into the horn's bony core)
95
what happens to calf at 6 months - to do with their horn growth?
frontal sinus starts extending into horn's bony core
96
what does horn fracture and dehorning of older animals risk?
risks sinus infection
97
need to watch vid for slides 24,25,26,27,28
98
What is the central sulcus?
The deep groove at the centre of the frog on the horses hoof
There are also lateral and medial sulcus
99
What is the bar on a horses hoof?
Where the hoof wall folds in on itself
There is a lateral and medial bar
100
What is the white line?
The continuation of the epidermal laminae, filled in with interlamellar horn. The white line isn't always the palest structure, have a look at the adjacent hoof wall
101
What is the hoof wall?
the middle layer of the hoof wall (the stratum medium) may contain pigment, which is why some horses' hooves are dark
102
What is the function of the grip?
The frog contains eccrine sweat glands so helps with a bit of grip
Compression of the frog when a horse walks will squash the digital cushion, in turn squeezing blood vessels in the hoof cartilages
103
What is the periople?
The slightly softer band of horn near the coronet
104
How does the calf or lamb's hoof not damage the cow's internal soft tissues during pregnancy?
The hoof is covered by a deciduous hoof capsule
This soft rubbery layer can be seen on newborn animal's hooves (calves, piglets, lambs and foals). It protect's the mother's soft tissues and will wear off as the animal walks.
105
How many digits do cattle have? Weight bearing and non weight bearing?
Cattle have 2 weightbearing digits, however also have 2 additional non-weightbearing digits either side.
From medial to lateral, they are numbered II - V.
II and V are called dewclaws, III is the medial claw, IV is the lateral claw.
106
7 differences between horns and antlers?
1. Horns develop in subcutis,
2. horns covered in keratin sheath,
3. horns never shed,
4. different species (horns bovids),
5. horns can have ridges,
6. horns have no branches,
7. horn core contains frontal sinus (cows)
107
7 similarities between antlers and horns?
1. Initially covered in epidermis,
2. contain bone,
3. located on frontal bone,
4. paired,
5. bigger/present more in males,
6. similar functions (defence, display),
7. get bigger with age
108
