Digestion 1 Flashcards

(99 cards)

1
Q

List the 5 functions of the digestive system

A

1) securing food
2) conducting and storing food
3) mechanical and chemical digestion
4) absorption of food
5) storage and disposal of waste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the 3 parts of the abdominal cavity and the sub parts

A

1) mouth
2) pharynx
3) alimentary canal
a. oesophagus
b. stomach
c. small intestines
d. large intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List and describe the main features of the mouth

A

1) maxillae and mandible - jaws
2) cheeks (buccae) and lips (labia)
3) outer vestibule - formed between lips/cheek when mouth is closed
4) mouth cavity proper - roofed by palate, laterally by teeth, and tongue on the floor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does the pharynx connect and where does the oesophagus sit in relation to it

A

the back of the nasal and oral cavities with the oesophagus sitting dorsal to the larynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Wall structure of the abdomen cavity

A

1) Inner lining layer (the mucosa)
- Transport nutrients and keeps out bacteria
2) Underlying connective tissue layer (the submucosa)
- Containing blood vessels and nerves
3) The major muscle layer (muscularis externa)
- Mixing and peristalsis
4) Outer connective tissue - serosa - lubricant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are intrinsic and extrinsic glands give an example

A

intrinsic - in walls and releases secretion into lumen eg - goblet cells
extrinsic - outside the walls and delivers secretions to lumen via ducts eg - salivary glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

regions of the abdomen name them

A

2 transverse, 2 sagittal divide abdomen into 9 regions
cranial - 1. xiphoid 2. left hypochondrial region 3. right hypochondrial region
middle - 4. umbilical region 5. left lateral (fank) 6. right lateral (flank)
caudal - 7. pubic 8. left inguinal 9. right inguinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the cranial, caudal and lateral boundry of the abdominal cavity

A

cranial - diaphragm
caudal - pelvic inlet
lateral - diaphragm, 3 muscles of the lateral abdominal wall - Internal and external abdominal oblique; transverse abdominal muscle and part of the pelvis (wing of the ilium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the dorsal and ventral boundary of the abdominal cavity

A

dorsal - the lumbar vertebrae, the sublumbar muscles and the arms (crura) of the diaphragm
ventral - The left and right rectus abdominis muscles (strap-like; either side of midline)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the sublumbar fossa and where is it found within abdominal regions

A

The sublumbar fossa (can look sunken on a cow) is contained in the dorsal aspect of the flanks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is peritoneum what is it composed of and its function

A

smooth shiny serious membrane which lines the abdominal and part of the pelvic cavity
composed of squamous epithelium which lies on connective tissue, containing blood vessels, nerves and lympatics
to secrete the watery peritoneal fluid that acts as a lubricant to decrease friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the peritoneal cavity enclosed by, what is it divided into and how much space is contained within

A

peritoneum and is divided into the peritoneal portion and the pelvic portion.
little space due to great bulk of viscera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List the 3 main types of peritoneum and describe them

A

1) Parietal peritoneum- is peritoneum attached onto the wall of the abdominal cavity
2) visceral peritoneum - is peritoneum lining the external surfaces of the viscera (soft internal organs).
3) connecting peritoneum - composed of double membranes: different types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

List the 3 types of connecting peritoneum

A

1) mesentery
2) omentum
3) ligament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the mesentery, examples and what it provides

A

peritoneum from the intestine to the dorsal wall of the abdominal cavity.

  • The Common or great mesentery - connects most of the small intestine to the abdominal roof at the level of the first and second lumbar vertebrae.
  • Mesocolon - attaches the colon (large intestine) to the abdominal roof and continues into the pelvic cavity as the mesorectum
  • Provides access to blood vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the omentum and 2 examples

A

peritoneum that connects the stomach
- Greater omentum- passes from greater curvature of stomach to the spleen to the dorsal lumbar wall. It encloses a potential cavity- the omental bursa. - must move to get to intestines and the fat content will vary depending on animal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the ligament (abdominal cavity) and what is it not concerned with

A

about connecting to the liver
-reflections of peritoneum between the viscera (internal organs of the abdominal cavity), or between viscera and the abdominal wall-usually not concerned with conducting vessels and nerves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

where does the kidney, liver and stomach sit in the abdominal cavity

A

Kidney sits dorsal and not covered in peritoneum unlike everything else - most dorsal
Liver sits right up against the diaphragm
Stomach sits right under ribs usually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

where does the dog stomach sit when empty moderately full and completely full

A

Empty - does not contact the abdominal wall
Moderately filled - lies against the xiphoid and left hypochondrial region
Completely full-lies primarily in contact with the xiphoid and umbilical regions ventrally, and the right and left lateral regions and can reach caudally to a transverse plane just caudal to the umbilicus. Sticking out of the rib cage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

name the two main types of teeth and types within

A

brachydont teeth
Hypsodont teeth
aradicular hysodont or hypselondont - no roots

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

characteristics of brachydont and hypsodont teeth

A

brachydont - short crowned teeth, sole tooth type of carnivores, have a limited period of growth and eruptiononce stop stop growing
Hypsodont - high crowned teeth found in herbivores and omnivores teeth adapted to high rates of wear. prolonged growth and eruption period, root develops sometime after eruption commences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

List the 3 main parts of a tooth

A

1) crown
2) neck
3) root

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe the crown of both types of teeth

A

the part of the tooth that is covered by enamel

  • brachydont teeth, comprises the entire tooth above the neck
  • hypsodont teeth: the ‘anatomical crown’ (body): comprises the clinical crown – the part that has erupted and the reserve crown – the part still beneath the gum line
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe the neck and the root of teeth

A

A slight constriction at the cemento-enamel junction (where the enamel and cementum meet), which is covered by free gingiva (gum) in normal healthy tooth. Present in brachydont teeth, absent in hypsodont.
-Root: Located within and anchored to the alveolus. Has no enamel. Has a foramen at its apical end through which vessels and nerves enter to supply the tooth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
enamel - where found, synthesized by and structure
crown only ameloblasts which are lost after eruption 96-98%mineral content, chiefly hydroxyapatite – a calcium phosphate complex that is the inorganic constituent of bones and teeth
26
dentine (dentin) produced by, structure, special characteristics
odontoblasts mineralised extracellular matrix similar to bone-approximately 70% mineral content, 30% organic components( including collagen fibres and mucopolysaccharide) sensitive as holes which extend into pup cavity and cause transmission of pain - in horse not due to calcification process but if trim enough will be no cells embedded in dentine
27
list and describe the different types of dentine
Primary – the outermost layer of dentine, is produced by the odontoblasts while they are located closest to the enamel layer during tooth formation befre eruption - Secondary –Laid down slowly and results in narrowing of pulp cavity with age. In brachydont teeth is produced after root formation complete. In horse teeth prevents pulp exposure at occlusal surface arising from normal wear. After eruption - thickens and makes the cavity narrower - one that takes up stain from food - Tertiary – Produced in response to injury or damage. May also be laid down in horse teeth to protect tip of pulp cavity from exposure.
28
cementum (cement) produced by, function and structure
cementoblasts some remain embedded surrounds and protects dentine of root and anchors the periodontal ligament and alveolar bone • In hypsodont teeth also contributes to bulk and strength of the crown • not as readily degraded as bone (e.g. during orthodontic work) • mineralised extracellular matrix similar to bone – approx 60-65% mineral content
29
dental pulp structure and things that lay within
connective tissue with abundant blood vessels, nerves - touch and pain both of which enter through apical foramen superior and inferior alveolar arteries through jaws superior maxillary branch of trigeminal nerve, inferior mandibular branch of trigeminal nerve
30
alveolus (socket) characteristics, other name and what is embedded within
Alveolar bone proper is the layer of bone lining the socket – also called the lamina dura (the hard layer) • The periodontal ligament is embedded in the alveolar bone proper • The socket follows the shape of root (the roots may be branched
31
periodontal ligament structure, function
ligament that suspends and anchors tooth in alveolus. • Allows some movement of tooth in socket and has some shock absorbing function to accommodate compression during chewing • Comprised of collagen fibre (formed from fibroblast cells) bundles called Sharpey’s fibres that connect lamina dura to cementum
32
Gingiva (gum) function and different types
Covers the alveolar bone and surrounds the teeth free gingiva – forms collar around the crown and is separated from the tooth by a space called the gingival sulcus attached gingiva - extends apically from the free gingiva to merge with the oral mucosa at the muco-gingival margin (junction between tough keratinised gingival mucosa and soft oral mucosa), is bound by collagen fibres to the underlying bone • Depth of sulcus is measured when assessing health of the tooth
33
What is the interdental papilla
gingival peak between adjacent teeth
34
what is the name for one, two and multiple sets of teeth and example
one - monophyodont - rodents two - diphyodont - most mammals multiple - polyphyodont - elephants
35
cell differentiation to form the dental sac
Bell stage - 1. The ectodermal cells lining the concave aspect of the enamel organ become the internal enamel epithelium 2. Cells lining the convex aspect become the external enamel epithelium 3. Between these two layers the cells become the star shaped cells of the stellate reticulum – functions to support enamel development 4. The uppermost layer of cells in the dental papilla become the odontoblasts which begin to produce dentine 5. The internal enamel epithelial cells differentiate into ameloblasts that begin to produce enamel
36
cell differentiation with the break down of the dental sac
- The root sheath breaks down and the inner layer of dental sac cells in contact with the dentine differentiate into cementoblasts that then lay down cement on outer aspect of dentine. - The middle layer of the dental sac (surrounds the enamel) differentiate into fibroblast rise to the periodontal ligament - outer layer of the dental sac gives rise to osteoblasts that form the alveolar bone
37
Differences in hypsodont teeth from brachydont
1) The enamel organ is longer and its surfaces may be folded 2) Eruption is slow and commences before root formation. 3) During eruption the hypsodont tooth is surrounded by the dental sac for a longer time so the enamel layer becomes coated with cementum
38
order the teeth from rostral to caudal and what is the difference between premolars and molars
incisors, canines, premolars and molars | premolars have deciduous precursors while molars dont
39
characteristics of incisors, canines, molars and premolars of dog teeth
incisors - tricuspid, sharp, single root canines - attack and defence, root much longer than crown molars and premolars - cutting and crushing, only occlude caudally - cannot grind P1 - 1 root upper P2 and P3 and rest lower cheek teeth - 2 roots rest - 3 roots
40
what are carnassial teeth what species in and function
dog - upper P4 and lower M1 are known as the ‘carnassial teeth’ - rostrally sharp for cutting caudally flat, blunt for crushing of bones, used for shearing - upper carnassial (P4) often infected due to crown damage
41
difference between cat and dog teeth
no blunt crushing surfaces as absent upper premolar 1 and lower premolar 1 and 2
42
describe the different type of teeth for a pig
incisors - needle teeth piglets born with 8 erupted deciduous teeth – these are the 4 third incisors and the 4 canines. Some farmers clip these to reduce injuries - lower incisors project forward for digging, are brachydont teeth Canines =’ tusks’ - Hypsodont teeth - used for tearing (directed laterally) - can get large in boars and so are regularly trimmed - cheek teeth- for crushing and grinding, have rounded cusps - are brachydont teeth
43
growth and eruption in horses
Hypsodont teeth in the horse continue to grow (laying down of new tooth in its apical part) until the age of 17, but eruption (protrusion through the gum from the alveolus) continues for life. Teeth growth and eruption must compensate for occlusal wear of 2-3mm/year.
44
characteristics of horse incisors - how labelled etc
- Hypsodont teeth - From medial to lateral labelled I1:‘central,’I2: ’middle’ and I3:‘corner’ incisors - enamel not continuous over occlusal (grinding) surface ⇒ exposure of dentine, primary, secondary (takes up stain), tertiary (white) - infundibulum = ‘cup with cementum’ or ‘mark - when cement almost disappears’ - disappears with age within have cement which takes up stain - pulp cavity - appears with age (protected by 2° and 3° dentine) = ‘dental star’ - protected by dentitne
45
describe canines in horses
most males have four that erupt from 4-6 years of age. Most mares – canines are absent or rudimentary Lie in the diastema between the incisors and premolars Usually classified as brachydont. They do have features of hypsodont teeth such as long reserve crown that makes extraction difficult, but they do not continue to grow
46
describe cheek teeth in horses
- First premolar – ‘wolf tooth’. A vestigial brachydont tooth that may be present in some animals (13-32% reported, possibly F>M), upper more common than lower. Usually erupts at 6-12 months of age and has no deciduous precursor. May require removal. Rest are hypsodont teeth Enamel is not continuous over occlusal surface, some dentine is exposed and cementum is present around the enamel crown Maxillary teeth are wider apart than mandibular – may result in formation of sharp points (can dig into teeth and cheek) on buccal aspect of maxillary and lingual aspect of mandibular cheek teeth that require filing down
47
describe incisors and canines in the ox
- no upper incisors or canines - replaced by hard fibrous dental pad - grip food between incisors and dental pad and tear by head movement - no continuous eruption – are brachydont - lower canines are incisor in form so dental formula may classify as incisor
48
describe cheek teeth in the ox and what species is similar and what makes examination of ox oral cavity easier
- increase in size from rostral to caudal - similar to horse – are hypsodont - arrangement of enamel ridges slightly different from horse, enamel stands out more - sheep wide diastema so can grab tongue
49
describe the incisors and canines in alpaca/llama
- Have a dental pad instead of some of the upper incisors, but retain the upper third incisor that is canine in appearance - Third upper incisor and upper and lower canines comprise the ’fighting teeth’ - present in males and females. Larger in males and can cause serious injury as a result of fighting so are often trimmed - cease growing at about 7 years of age - lower canine close to important structures like nerves so have to be careful and root is close to 3rd incisor root - Lower incisors may require trimming if overgrown – should be occluding with the dental pad and if not can grow above top lip some do trim - usually as a result of malocclusion- if teeth not aligned properly not grinded down properly
50
rabbits - what type of teeth there and what absent
hypselodont incisors and cheek teeth - diphyodont with all temporary teeth replaced 35 days old canines are absent and long diastema
51
key characteristics of rabbit incisors
- enamel only rostrally ⇒ sharp, chisel-shaped incisors as they occlude with each other (upper and lower) Function - tear off vegetation, gnaw hard materials - 4 upper incisors (2 pairs of incisors one pair rostral to the other)– the smaller ’peg teeth’ lie immediately caudal to the first incisors in the upper arcade. Two lower incisors, rostral is larger than cordal - rapid growth rate – up to 8-10mm per month (incisors), 3-4mm/month (cheek teeth) - if malocclusion then can quickly run into problems
52
rodents what type of teeth in each type
two upper and two lower incisors, as in rabbits these are hypselodont • Herbivorous rodents eg. guinea pig – cheek teeth also hypselodont • Omnivorous rodents eg. mouse – cheek teeth are brachydont • Most rodents (not guinea pigs) have a yellow-orange pigment in the superficial enamel layer on the incisors. Most species are also monophyodont (single set of teeth)
53
Dog/Cat how to tell age by teeth
1) eruption times when young - no teeth erupted at birth | 2) wear of teeth - older - lower arcade generally more wear than upper
54
horse how to tell age by teeth
1) eruption of incisors - most accurate - deciduous are smaller and white permanents are more rectangular, yellowish, larger 2) changes to the incisor occlusal surface 3) changes in shape of occlusal surface - The cross section changes shape from oval (mesiodistal direction), through trapezoid then triangular and finally oval in a labiolingual direction (narrow) - not accurate due to gradual change 4) shape of upper corner incisor - 5-9 crown wide 9-10 upper corner square over 10 -taller than wide 5) curvature of dental arch of lower incisors - semicircle to straighter 6) angle of incisors - decrease in angle 7) hook on upper corner incisor - irrelevant 8) Galvayne's groove (middle of the teeth) - irrelevant
55
what is involved in the changes to the incisor occlusal surface in horse teeth
Dental star: - between the labial edge of the incisor and the infundibulum, appears when tooth worn down to tip of pulp cavity - Consists of dentin that occludes the pulp cavity as the tooth is worn down - Changes shape and position with age - Next most accurate feature after eruption times Dental cup/mark: - the infundibulum – when empty is the ‘cup’, when worn down to cement filled bottom of infundibulum is called the ‘mark’. Eventually disappears – times not reliable
56
how to tell the age of an ox by the teeth
Appearance of the incisors and eruption times of the permanent incisors are used • Some incisors may already be erupted at birth, eruption of all deciduous incisors complete by week 4 • Deciduous incisors are smaller and narrower, whiter, with a more triangular shape (narrower base ) than permanent incisors • Deciduous incisors are initially short and broad, but become longer and narrower as the animal approaches 15-18 months of age • Stages are milk tooth (no permanents), 2 tooth (centrals erupted - 2 years), 4 tooth (middles - 2.5 years) 6 tooth (laterals) and 8 tooth/full mouth (corners - 3 years) • By 5 years all incisors are in wear and then the occlusal table is observed for ‘levelling’ (the ridges on the lingual surface disappear and the surface becomes smooth and convex): 6 years (centrals) 7 years (middles) 8 years (laterals) and 9 years old (all incisors levelled)
57
how to tell age of sheep by teeth
similar to ox usually no teeth at birth - can get broken mouth and gummy mouth
58
boundary of the oral cavity
Rostral - lips Laterally - cheeks Ventral - floor of oral cavity beneath the tongue Caudal - palatoglossal arch - mucosal layer from soft palate to root of the tongue Dorsal - palate - roastrally hard palate cordally soft palate
59
Rugae prehension cornified cells
raised ridges in the hard palate grasping Cornified cells have lost their nucleus and are filled with a keratin protein matrix that, among other roles, provides increased resistance to mechanical forces
60
List the layers of the oral mucosa and describe them
Epithelium - stratified squamous epithelial cells resting on a basement membrane. In parts of the oral cavity the epithelium is ‘keratinised’ (cornified) more in herbivores than carnivores Lamina propria – a layer of connective tissue (Lamina muscularis – 3rd layer seen in other mucosae, but not oral mucosa – this absence results in an indistinct margin between lamina propria and submucosa) Submucosa: is a further layer of connective tissue that in certain regions of the oral cavity (lips, tongue, palate, cheeks) contains minor salivary glands Muscular tunic: where present (lips, cheeks, soft palate) comprises skeletal muscle. (is mostly smooth muscle elsewhere in the digestive tract)
61
list and describe the layers of the lips
Layers: • mucosa: epithelium keratinized in horses and ruminants, not in carnivores or pigs • submucosa: contains minor salivary glands (labial glands) with ducts opening through oral mucosa • muscle, tendon • skin
62
What are the muscles of the lips and what do they do and what nerve innervated by
orbicularis oris (around the mouth) – encircles opening of oral cavity within lips and acts to close lips • other muscles (variation between species) - caninus (snarling - dog) - levator nasolabialis – lifts nose and upper lip - levator labii superioris – lifts upper lip - sits rostrally to upper lip 7 - 7 - depressor labii inferioris (not dog, cat) – depresses lower lip • all innervated by cranial nerve VII (7) (= Facial N.)
63
list some species variation of the lips
loose with thin, serrated margin in dog - sensitive and mobile in horse - ox: insensitive and thick, lined with buccal papillae - philtrum (dogs, cats, camelids, sheep): cleft marking division of upper lip (feature allows closer grazing by sheep compared with cattle) • extent in relation to dental arcade varies with diet type - affects size of ‘gape’ -one result is different methods of drinking - e.g. herbivores smaller gape - can suck up liquids vs. carnivores wide gape - tend to lap liquids
64
cheeks what is the characteristic of the mucosal epithelium, muscles and innervation
Mucosal epithelium may be keratinized, depending on the particular area and the species • in ruminants and camelids buccal mucosa has caudally directed conical buccal papillae - mechanical function bring food back into mouth • Buccal glands = minor salivary glands in submucosa • Muscular tunic (forms muscle of the cheek) formed by the buccinator muscle - functions to return food from vestibule to oral cavity proper (Facial N/CN VII) - innovate muscle of facial expression
65
function of the palate and what composed of
Forms roof of oral cavity – separates oral cavity from nasal cavity • comprised of hard palate rostrally and soft palate caudally Hard palate • bone covered by thick mucosa which forms ridges (rugae) - guide food backwards • Mucosal epithelium keratinized, submucosa dense and closely attached to periosteum (fibrous layer on outer surface of bone) • Ruminants have a dental pad = rostral portion of hard palate, with heavily keratinized mucosa overlying a thick layer of dense connective tissue • Palatine glands (minor salivary) are present in all domestic species except pigs • bone= incisive, maxilla and palatine bones Soft palate • Comprises a dorsal and a ventral mucosal layer separated by connective tissue, minor salivary glands (palatine) and 3 paired muscles which shorten, tense and raise the palate
66
the tongue, the different structures and what composed of
* root - attached to hyoid apparatus * body - attached to mandible * apex – free rostral portion * connected to the floor of oral cavity by the frenulum * The mucosal epithelium on the dorsum of the tongue is thick and keratinised and bears numerous lingual papillae. Mucosal epithelium on the ventral aspect is non- keratinised. * The mucosa has abundant capillaries and arteriovenous anastomoses and these participate in thermoregulation (eg heat loss – panting) * Minor salivary glands are in the submucosa (lingual glands). Serous gustatory glands (sense of taste, secret serous matter to dissolve food so taste buds can sense it) open into the sulcus of the vallate papillae
67
List the 7 types of papillae
1) filiform (thread-like) 2) conical (cone shape) 3) lentiform (lense shape)/Lenticular 4) Fungiform (mushroom shaped) 5) Foliate (leaf like) 6) Vallate/circumvallate 7) marginal papillae
68
Describe the Filiform, conical, lentiform papillae
- Filiform (thread like): mechanical function, cover most of tongue surface, short, point caudally, keratinised, large in cats, give grip to tongue and assist with food movement and comb fur for cats - Conical (cone shape): also mechanical function-larger than filiform papillae ⇒present on root of tongue in dogs cats and pigs, on torus linguae in ruminants (also inside cheeks and lips) - Lentiform (lense shape)/Lenticular: mechanical function, round to ovoid, present on torus linguae of ox
69
Taste buds, where present, structure, what nerves involved
clusters of specialised cells embedded in the epithelium of gustatory papillae – have a small opening, the taste pore at the epithelial surface and their base is in contact with fibres of nerves that convey sense of taste to brain from tongue (Facial N/ VII rostral and Glossopharyngeal N/ IX caudal). NB. Taste buds are also present in soft palate, epiglottis and other areas of oral cavity and pharynx
70
Nerves involved with tongue innervation | motor, sensory and taste
Motor: - all (intrinsic and extrinsic) muscles innervated by cranial nerve XII (hypoglossal) • Sensory: general sensation: - rostral two-thirds – cranial nerve V (trigeminal-mandibular division) - parts of the tongue - caudal third – cranial nerve IX (glossopharyngeal) • taste: - rostral two-thirds – cranial nerve VII (facial) - caudal third – cranial nerve IX (glossopharyngeal)
71
species differences of the tongue - ruminant, carnivores, horse
* torus of ruminant tongue - enlarged body with lingual fossa (can get infections within this area as foreign bodies loge themselves there) rostral to it. * Carnivores have a lyssa: (prominent in dogs – responsible for median groove/sulcus in tongue, mainly adipose tissue in cats) rod shaped fibrous body in median plane beneath ventral mucosa * horse tongue has median dorsal lingual cartilage (lingual body) under dorsal mucosa
72
what type of muscles in the tongue and name important ones
* The tongue is supported by mylohyoideus m. – the most ventral muscle between the paired mandibles and just dorsal to the mylohyoideus, the geniohyoideus m.–that extends from the chin to the hyoid apparatus. * Intrinsic muscles (located entirely within tongue):- longitudinal, transverse and vertical bundles, protrude tongue, complex local movements - allows tongue to be shaped, complex movements * Extrinsic muscles: are muscles which originate on the hyoid apparatus (styloglossus, hyoglossus)or mandible (genioglossus) originate in chin and insert in the tongue - act to depress, protrude or retract the tongue
73
Name the 3 jaw closing muscles and what innervated by
1) temporalis 2) masseter 3) pterygoids All innervated by mandibular branch of trigeminal nerve (cranial nerve V)
74
temporalis what is it, its origin, what it does and the size
jaw-closing muscles • Origin on extensive area of lateral surface of cranium (frontal, parietal, temporal and occipital bones) and insertion on coronoid process of mandible • contraction pulls mandible upward • large in carnivores; relatively small in herbivores
75
masseter what is it, its origin, where attaches and the main actions
A jaw closing muscle origin - maxillary region of skull and zygomatic arch • insertion - wide area of caudal mandible • main actions - to raise mandible (close jaws) - move lower jaw laterally when contracted on one side (origin lateral to insertion); greater sideways movement in herbivores than in carnivores - protrude lower jaw
76
Pterygoids what is it, its origin, where attaches and the main actions
jaw closing muscle - comes in lateral and medial medial to mandible • origin - pterygopalatine region of skull • insertion - medial face of mandible • actions - close jaws - move lower jaw medially when contracted on one side (origin medial to insertion) - protrude lower jaw
77
List the jaw opening muscle what innervated by and origin
Digastricus - 2-bellied • Innervated by both mandibular branch of trigeminal (rostral belly) and facial (cranial nerve VII; caudal belly) - origin on occipital bone of skull, caudal to temporomandibular joint - insertion on mandible
78
Temporomat processes involved, what is it divided into and how, what is it like in herbivores and carnivores
* articulation between zygomatic process of temporal bone of skull and condyloid process of mandible - of skull and madible * In all domestic species is divided into a dorsal and ventral compartment by an intra articular disc – arrangement thought to allow complex movements to occur at the joint * Flat articular surfaces (allows sliding movement) in herbivores allow lateral to medial excursions of mandible for grinding of food between cheek teeth – action relies on coordination between pterygoids and masseters on each side, these muscles therefore relatively larger in herbivores * Bony processes around the joint restrict movement to hinge like action in carnivores – emphasis is usually on vertical force to grasp and kill prey. Temporal muscle is typically the most important in these species
79
3 parts of the pharynx
1) Oropharynx: ventral to soft palate from palatoglossal arches to base of epiglottis and caudal margin of soft palate 2) Nasopharynx: dorsal to hard and soft palate from choanae (internal nostrils entrance to nasopharynx) to intrapharyngeal ostium (where digestive and respiratory tracts cross over) at caudal boundary of soft palate 3) Laryngopharynx: Dorsal to larynx from intrapharyngeal ostium to opening of oesophagus
80
List the different types of imaging which id better if have fluid in abdomen
1) radiology 2) ultrasound - better 3) scintigraphy (nuclear medicine) 4) computed tomography (CT) 5) magnetic resonance imaging (MRI)
81
what is it called when stomach filled with gas and rotates and twists
Gatric Dilation Volvulus
82
List the oral defense mechanisms
1) oral mucosa 2) saliva 3) crevicular fluid 4) chewing and swallowing 5) anatomy of the tooth
83
characteristics of the oral mucosa that allow it to defend against microbes and some weaknesses of that area
- if intact few microbes can penetrate - in lamina propria lymphoid cell that combat another microbes weakness - - once inflamed point of weakness as by-products create destruction themselves - if still have deciduous teeth with permanent can share gingival cuff - compromised cuff
84
characteristics of the saliva that allow it to defend against microbes and what does reduced salivary volume effect and lead to
- Proteins such as salivary peroxidase, lysozyme and lactoferrin are antibacterial. - Histatins (a family of salivary proteins) are antifungal and limit growth of oral yeast. - Secretory immunoglobulins (A and M) are produced locally by B cells within the salivary glands. Reduced Salivary Volume affects taste and appetite and associated with difficulty in swallowing - Significant reduction - xerostomia increases risk of oral complications Autoimmune disease can affect gland output Chronic renal disease, diabetes etc.
85
characteristics of the crevicular fluid that allow it to defend against microbes
With an increase in plaque accumulation on tooth increase in fluid which contains - Immunoglobulins (Ig G, A, M in addition to others). - macrophages and T and B cells, which migrate from underlying blood vessels.
86
characteristics of the anatomy of the tooth that allow it to defend against microbes
1) Shape of the tooth Conical shape less area for debris to accumulate and enamel bulge pushes food away from sulcus 2) Enamel is very smooth and hard Makes difficult for plaque to accumulate once dentine exposed easier due to porous nature 3) Continual layering of dentine Secondary dentine continual laid overtime to provide more protection for the pulp Tertiary dentine can be laid at a faster rate if tooth is traumatised
87
List and describe the 3 central causes of periodontal disease
1) bacteria - is needed - disrupted of junctional epithelium produce pockets and changes in connective tissue, loss of alveolar bone 2) Local secondary contributing factors Tooth crowding and malocclusions (especially dogs with short wide skulls) Retention of deciduous teeth (the small dog breeds) Mouth breathing and xerostomia (dries the mucosal surfaces) Plaque retentive diets (influence the progression of disease) Concurrent diseases such as diabetes, renal disease, diseases with immunocompromise 3) Genetic predisposition Has been demonstrated in humans so likely in animals
88
what precedes PD and when is it reversible
gingivitis - reversible then but not once PD
89
define gingivits and periodontitis in what it causes
GINGIVITIS: Is the reversible inflammation of the gingiva associated with plaque. Oedema of the gingival margin can produce ‘pseudo-pockets’. PERIODONTITIS: Is the irreversible loss of CT attachment with true pocket formation. It is preceded by gingivitis and it increases in severity and prevalence with age.
90
List some key features of PD and what it can lead to
- not continuous in activity - local or general and seems to increase with age- animal often presented with advanced disease - associated with other diseases in other organ systems - disease of the bone - leads to tooth loss and more severe in maxilla - can lead to oronasal fistulas - holes in rostral part of the mouth
91
stages of periodontal disease
grade 0 - healthy gingiva - no signs of inflammation 1 - marginal gingivitis 2 - oedema and inflammation of gingiva calculus 25% crown 3 - calculus 50% crown extends to sulcus beginning pocket formation 4 - severe bone loss, deep pockets, mobility and loss of teeth
92
what is pellicle, plaque and calculus
Pellicle - Is a protein film that forms on the surface enamel by selectively binding of glycoproteins from saliva that prevents continuous deposition of salivary calcium phosphate - Bacteria free layer can serve as attachment medium for bacteria which turns into plaque - It forms seconds after brushing Plaque - mass of bacteria firmly adherent to a pellicle - It is a biofilm Calculus - Mineralized plaque which provides a suitable surface for plaque bacteria to hide and survive
93
stages of Pellicle and plaque deposition and what it leads to
1st event: saliva bathes the tooth •Attachment of glycoproteins / mucopolysaccharides 2nd stage involves bacterial colonisation -> a lawn of mainly Gram +ve bacteria (good bacteria) •Migration of organisms into the gingival sulcus. •Metabolic by-products attract WBCs -> inflammation! 3rd stage is ‘maturation’ of ‘good’ plaque to ‘bad’ …mainly Gram -ve …can occur in as little as 2 weeks. Deep periodontal pockets provide an anaerobic environment for these virulent strains of bacteria and allows them and their toxins to enter bloodstream
94
control of plaque list the ways and when needed
1) Mechanical - brushing, professional dental treatments - allow access to sulcus, abrasive diets Eg - hand scale, ultrasonic scale 2) Chemical means Eg - CLR rinse (chlorhexidine) Best to have combination but mechanical before chemical as need to disrupt plaque biofilm first for chemical to penetrate Once disease is established thorough dental treatment is needed under general anaesthetic as homecare is only a prevention
95
options for homecare for dental
1) Mechanical - Tooth brushing - Diet - Chews - Toys - Pigs ears 2) Chemical - involves applying to teeth which can be quite difficult - Chlorhexidine based products (hexarinse) - Zinc ascorbate (maxiguard)
96
tooth resorption what does it present as and how to tell
- Lesions are characteristic by a defect of cementum and dentine in enamel - Present as a progressive resorption of the dentine beginning at the cemento-enamel junction - Very difficult to tell on the surface so must do an x-ray to determine if the tooth is degrading
97
clinical appearance and aetiopathology
- Most common in the mesial premolar teeth however can be one any tooth - Inflammation of the gingiva is present but may be missed and more frequently seen in buccal surface - Resorptive lesions are painful and can lead to depression, lethargy unsure about cause most likely multi-factorial
98
pathological changes for tooth resorption
- Terminology based on resorption by odontoclasts (a type of cell involved with reabsorption of teeth) - Can have internal resorption on the wall of the pulp chamber - External resorption on the external surface of the root Activity of odontoclast 1) Resorptive phase - actively resorbing dentine and cementum 2) Reparative phase - may occur concurrently depositing bone-like (or cementum-like tissue) into these defects Most lesions appear to have both phases together - like bone remodelling
99
treatment for tooth resorption
Restore - many different ways with very low success rates and very technique sensitive so poor technique will lead to poor results - Fluid varnishes - Glass ionomer - chemically bond to dentine however 65% failure Extract - generally the recommended treatment