Digestion 1 Flashcards

Question

enamel - where found, synthesized by and structure

Answer 1

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

Answer 2

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

Answer 3

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.

Answer 4

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

Answer 5

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

Answer 6

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

Answer 7

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

Answer 8

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

Answer 9

gingival peak between adjacent teeth

Answer 10

one - monophyodont - rodents two - diphyodont - most mammals multiple - polyphyodont - elephants

Answer 11

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

Answer 12

- 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

Answer 13

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

Answer 14

incisors, canines, premolars and molars | premolars have deciduous precursors while molars dont

Answer 15

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

Answer 16

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

Answer 17

no blunt crushing surfaces as absent upper premolar 1 and lower premolar 1 and 2

Answer 18

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

Answer 19

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.

Answer 20

- 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

Answer 21

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

Answer 22

- 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

Answer 23

- 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

Answer 24

- 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

Answer 25

- 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

Answer 26

hypselodont incisors and cheek teeth - diphyodont with all temporary teeth replaced 35 days old canines are absent and long diastema

Answer 27

- 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

Answer 28

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)

Answer 29

1) eruption times when young - no teeth erupted at birth | 2) wear of teeth - older - lower arcade generally more wear than upper

Answer 30

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

Answer 31

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

Answer 32

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)

Answer 33

similar to ox usually no teeth at birth - can get broken mouth and gummy mouth

Answer 34

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

Answer 35

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

Answer 36

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)

Answer 37

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

Answer 38

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.)

Answer 39

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

Answer 40

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

Answer 41

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

Answer 42

* 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

Answer 43

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

Answer 44

- 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

Answer 45

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

Answer 46

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)

Answer 47

* 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

Answer 48

* 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

Answer 49

1) temporalis 2) masseter 3) pterygoids All innervated by mandibular branch of trigeminal nerve (cranial nerve V)

Answer 50

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

Answer 51

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

Answer 52

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

Answer 53

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

Answer 54

* 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

Answer 55

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

Answer 56

1) radiology 2) ultrasound - better 3) scintigraphy (nuclear medicine) 4) computed tomography (CT) 5) magnetic resonance imaging (MRI)

Answer 57

Gatric Dilation Volvulus

Answer 58

1) oral mucosa 2) saliva 3) crevicular fluid 4) chewing and swallowing 5) anatomy of the tooth

Answer 59

- 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

Answer 60

- 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.

Answer 61

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.

Answer 62

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

Answer 63

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

Answer 64

gingivitis - reversible then but not once PD

Answer 65

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.

Answer 66

- 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

Answer 67

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

Answer 68

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

Answer 69

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

Answer 70

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

Answer 71

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)

Answer 72

- 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

Answer 73

- 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

Answer 74

- 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

Answer 75

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

Digestion 1 Flashcards

(99 cards)