Lectures Flashcards
Name the regions of the abdomen.
From cranioventral clockwise : Xiphoid, left hypochondral, left flank, left inguinal, pubic, right inguinal, right flank, right hypochondral - and umbilical in the middle
What is the cranial region of the abdomen bounded by?
Xiphoid cartilage and the L and R hypochondral
What is the middle region of the abdomen bounded by?
Umbilical in middle, L and R flank either side
What is the caudal region of the abdomen bounded by?
Pubic area in the middle, L and R inguinal either side
What are the three lateral muscles of the abdominal wall? Which order are they in?
From superficial to deep: External abdominal oblique (travels cranial to caudal), Internal abdominal oblique ( travels caudal to cranial), Transverse abdominus (travels dorsoventrally)
What is the term for a midline vental surgical incision?
Midline coeliotomy
Which muscle forms the ventral boundary of the abdominal cavity
Left and right rectus abdominus
The labial surface of the tooth faces the
Lips
The buccal surface of the tooth faces the
Cheeks
The lingual surface of the tooth faces the
Tongue
The vestibular surface of the tooth faces the
Lips or cheeks depending on its location
Interproximal or interdental surfaces face
Teeth in the same arcade
The mesial surface of a tooth faces the adjacent tooth that is
Closest to midline
The distal surface of a tooth faces the adjacent tooth that is
Furthest from midline
The crown is the
Part of the tooth that is covered in enamel
What is the difference between the clinical crown and the reserve crown?
In hyposodont teeth only. The reserve crown is the portion of the crown that remains beneath the gumline.
What is the name of the tooth section that has no enamel coating?
The root
Which substance forms the outermost layer of hypsodont teeth?
Cementum
Which substance occurs in both the root and crown of brachydont teeth?
Dentine
Eruption commences before root formation in which tooth type?
Hypsodont
Which cells synthesise enamel?
Ameloblasts
What features of enamel make it an effective tooth covering?
- strong and smooth to protect tooth from mechanical wear and infection
- forms sharp ridges to assist with mastication
Which cells synthesise dentine?
Odontoblasts
What is the location and function of primary dentine?
It is the second layer after the enamel. It functions to protect the pulp cavity if the enamel layer becomes compromised
What is the location and function of secondary dentine?
Laid down deep to primary dentine in response to mechanical stress on the tooth. Functions as a second line of defence for the pulp cavity. Takes up plant matter stain.
What is the location and function of tertiary dentine?
Laid down deep to secondary dentine in response to tooth injury or damage. Last line of defence for the pulp cavity
Three functions of cementum?
- Surrounds and protects the pulp cavity in the root
- Anchors the periodontal ligament
- Contributes to bulk of crown in hypsodont teeth
Three functions of the alveolus?
- Attaches the periodontal ligament to the jaw
- Surrounds and supports the tooth and its root
- Cancellous bone absorbs some shock
Name the four fibre types of periodontal ligament.
Crest, horizontal, oblique, apical
Which part of the primordial tooth become ameloblasts?
Inner enamel epithelium
Which part of the primordial tooth becomes the pulp cavity?
The dental papilla
Which part of the primordial tooth becomes the odontoblasts?
The uppermost layer of the dental papilla
Which primordial structure becomes the cementoblasts?
The inner layer of the dental sac
Which primordial structure becomes the periodontal ligament?
The middle layer of the dental sac
Which primordial structure becomes the osteoblasts?
The outer layer of the dental sac
The palatine surfaces of the tooth faces the
Hard palate - upper arcade teeth only
True or false - a 5 year old horse is likely to have roots present for his hypsodont teeth.
False. Horses may not develop tooth roots until 17 years of age due to continuous tooth growth.
The greater the ______ content, the stronger the tooth material is (enamel vs. cementum vs. dentine)
Hydroxyapetite (a calcium phosphate complex)
Which tooth layer takes up the plant material stain?
Secondary dentine and cementum that occurs above the gumline in herbivores
Why is floating horse teeth possible?
Because the dentine at the clinical crown surface is not sensitive, owing to calcification of the extending odontoblast processes at this level.
Periodontal ligaments can regenerate. Which cells produce the periodontal ligament and what is it made of?
Fibroblasts - formed from collagen bundles called Sharpey’s fibres.
What does ‘diphyodont’ mean?
Having of two sets of dentition (one deciduous, one permanent). Animals may also be monophyodont or polyphyodont e.g elephants
In tooth development, what structure does the primordium form?
The permanent tooth
List the layers, from superficial to deep, of a late stage developing tooth
Stellate reticulum, ameloblasts, enamel, dentine, pre-dentine, odontoblasts, dental pulp
What defines tooth ‘growth’ phase?
The laying down of enamel. Once this has ceased, formation of the root begins.
What is the dental formula for a dog?
3142/3143 x 2
Which teeth are known as carnassials in dogs?
Upper PM4 and Lower M1
What is the feline dental formula?
3131/3121 x 2
What is the dental formula for a pig?
3143/3143 x 2
What sort of teeth are tusks in pigs (brachy or hypso)?
Hypsodont, project laterally, used for fighting
What sort of teeth are the lower incisors in pigs? What are they used for?
Brachydont - project rostrally, used for digging
What is the equine dental formula?
31(0)3(4)3 / 31(0)3(4)3 x 2
- may be no wolf tooth or canine present
What sort of tooth is the wolf tooth (brachy or hypso)?
Brachydont
On which surfaces would you be concerned about sharp enamel ridges developing in a horse?
Buccal area of the maxillary arcade and lingual area of the mandibular cheek teeth
What is the dental formula for a cow /sheep?
0033/3133 x 2
What is the nature of ruminant incisors (hypso or brachy)?
Brachydont
True or false: The more level a cow’s incisors are, the younger she is.
False. The incisors start off oblique and wear to level with age.
In which species does the fighting tooth occur? Which tooth is it? What sort of tooth (brachy/hypso)?
Alpacas, upper incisor 3, hypsodont.
What is the lapine dental formula?
2033/1023 x 2
What creates the chisel shape of the peg teeth in rabbits?
Rostral surface has enamel coating, but caudal has dentine, allowing it to wear
What does it mean to have hypselodont teeth?
They never stop growing throughout life, and never form a root.
How is it possible to trim rabbit incisors without anaesthesia? Is it recommended?
Because the pulp cavity only projects 3mm above the gumline, so much of the incisors are not innervated. It is not recommended to do this because the cause of the protruding incisors may lie deeper in the oral cavity, which is difficult to examine without GA or sedation
True or false : rats have hypselodont incisors and brachydont cheek teeth.
True
What are the rough eruption times for dog teeth?
Deciduous: 4 - 6 weeks
Permanent: 4 - 6 months
What are the rough eruption times for cat teeth?
Deciduous: 2 - 6 weeks
Permanent: 4 - 7 months
What are the eruption dates for the deciduous incisors of a horse?
I1 = 0 - 1 weeks I2 = 4 - 6 weeks I3 = 6 - 9 months
What are the eruption dates for the permanent incisors of a horse?
I1 = 2.5 years I2 = 3.5 years I3 = 4.5 years
In horse teeth, the hook of the upper corner incisor tends to appear around __ years of age?
10 years approx
What does ‘heterodonty’ mean?
The differing in shape and function of teeth within a species’ mouth to allow particular tasks to be performed.
True or false: In most cases, premolars have a deciduous precursor whilst molars do not.
True. The exceptions are PM1 in carnivores and horses.
Describe the morphology of carnassial teeth.
Rostrally sharp for cutting, caudally flat and blunt for crushing.
True or false: the molars of dogs and cats are adapted to grind bones.
False. Carnivores cannot ‘grind’ at all, only crush (not cats), cut and tear
When the cup has almost completely worn away, the remaining dark speck is known as ___ and it is composed of ____
The mark, cementum
The star appears on the labial side of the occlusal incisor surface. It represents _____ covered by _____?
the pulp cavity covered by dentine
The cup is also known as the __?
Infundibulum.
Wolf teeth are slightly more likely to occur in which arcade?
Upper.
Describe the dental pad.
Thick, keratinised piece of tissue in place of upper incisors that binds to bone allowing prehension of large mouthfuls
Describe the incisors of a 4 year old ruminant.
All four permanent teeth have erupted. Minimal wear.
Describe the incisors of a 7 year old ruminant.
Both the first and second incisors have levelled and the neck has emerged from the gums.
By what times are the permanent incisors of a horse in wear? (wear takes 6 months from eruption)
I1 = 3 years I2 = 4 years I3 = 5 years
What is the white spot sometimes seen in the centre of the star in the horse?
Tertiary dentine.
What are the rough eruption times for the central, middle, lateral and full mouth incisors in cattle?
Centrals = 2 years
Middles = 2.5 years
Laterals = 3 years
Full mouth = 4 years
Sheep are the same except may be two-tooth by 1.5 years
Which species have keratinised epithelia lining their lips?
Horses and ruminants
Which species do not have keratinised epithelia lining their lips?
Pigs and carnivores
What is the caudal barrier of the oral cavity?
The palatoglossal arch.
Which layer of the oral cavity contains the salivary glands?
The submucosa.
Describe the location and function of orbicularis oris.
Lies within the lips. Encircles the oral cavity opening and acts to close the lips.
Describe the location and function of levitator nasolabialis. Which cranial nerve innervates it?
Inserts into and raises the nose and upper lip. CN Vii (facial nerve).
Describe the function of levator labii superioris. Which cranial nerve innervates it?
Lifts the upper lip. Occurs deep to levitator nasolabialis. CN Vii (facial nerve)
What is the function of buccal papillae? Name one species in which they are present.
Direct food from the oral cavity toward the pharynx e.g camelids, ruminants.
Describe the location and function of the buccinator muscle. Which cranial nerve innervates it?
Occurs caudal to the lips in the cheeks. Contracts to form muscular tunic that returns food from the vestibule to the oral cavity proper. CN Vii (facial nerve)
Name one species specific adaptation of the palate.
The dental pad.
True or false - the palate contains salivary palatine glands.
True. The only domestic species without palatine glands is the pig.
True or false - the soft palate participates in deglutition.
True. It contains three paired muscles which shorten, tense and raise it.
True or false - the hyoid apparatus lies within the maxilla.
False. The hyoid apparatus lies within the mandible.
True or false - the tongue root attaches to the hyoid apparatus.
True (the basihyoid, specifically)
Which structure of the dog oral cavity is particularly involved in thermoregulation?
The frenulum - highly vascular, passing blood through the frenulum that is exposed plus panting will cause the blood to cool down.
Where specifically in the tongue do the gustatory glands occur?
In the sulci bordering the vallate papillae.
Name the four mechanical tongue papillae types.
- Conical (most species, though location varies slightly)
- Lentiform/lenticular (ox, torus linguae)
- Marginal (newborn dog and pig, rostral tongue)
- Filiform (all species, largest in cats, smallest in horses, assist with food grip and grooming)
Name the three gustatory tongue papillae types.
- Fungiform
- Foliate (form parallel folds, absent in cats and ruminants)
- Vallate (most species, location demarcates junction between body and root of tongue)
The lingual fossa occurs rostral or caudal to the torus in ruminants?
Rostral.
Name the five extrinsic muscles of the tongue.
Genioglossus Hyoglossus Mylohyoideus Geniohyoideus Styloglossus SHMGG
Describe the orientation and action of mylohyoideus.
Runs transversely, ventral to the tongue from the medial L mandible to the medial R mandible. Acts to lift the tongue dorsally to press against the palate
Describe the orientation and action of geniohyoideus.
- genio = chin
Paired, strap-like muscles running cranio-caudal from the basihyoid to the chin. Draws the tongue toward the basihyoid (caudally)
Describe the orientation and action of styloglossus.
Runs from the stylohyoid bone to the tongue, acts to draw the tongue caudally. Has three heads inserting onto the tongue.
Describe the orientation and action of hyoglossus.
Runs from the tongue root to the basihyoid, acts to retract and depress the tongue.
Describe the orientation and action of genioglossus.
- genio = chin
- glossus = tongue
Occurs within the frenulum - runs from the medial mandible to the tongue. Acts to depress and protrude the tongue
True or false - digastricus acts to open the jaw and runs from the paracondylar process of the occiput to the ventrolateral mandible.
False - digastricus inserts onto the ventromedial mandible.
Which cranial nerve innervates the extrinsic muscles of the tongue?
The hypoglossal nerve.
Sensory innervation to the tongue is provided by how many cranial nerves?
Two - CN V to the rostral two thirds, CN IX to the caudal third.
True or false - the facial nerve participates in detection of taste at the tongue.
True.
The muscles that close the mouth are innervated by which cranial nerve?
Trigeminal (CN V)
Name the three muscles associated with closing the jaws.
- Temporalis
- Masseter
- the Pterygoids
Describe the orientation and action of temporalis.
Originates on extensive area of lateral cranium and inserts at the coronoid process of the mandible. Contracts to pull mandible upward. Larger in carnivores.
Describe the orientation and action of masseter.
Originates at the maxillary skull and zygomatic arch, inserts at the caudal mandible over a wide area. Acts on the mandible to raise it, move it laterally and protrude it. Larger in herbivores.
Describe the orientation and action of the pterygoid muscles.
Paired - lateral and medial. Originate at the pterygopalatine region of the skull and insert at the medial mandible. Work with masseter to move mandible laterally (chewing). Also close and protrude lower jaw.
Which two bones articulate to form the temperomandibular joint?
The zygomatic processes of the temporal bone and the condyloid processes of the mandible.
True or false: the flatter articular surfaces at the TMJ in herbivores is an evolutionary adaptation to the herbivorous diet.
True. The flatness allows greater range of lateral movement at the joint, facilitating grinding of the jaw. Carnivore TMJs operate in a hinge-like fashion as they are constricted by bony processes.
True or false - herbivores tend to have a larger temporalis muscle (relative to their size) than carnivores.
False. Temporalis’ main function is to close the jaws, which is more important in predatory animals. Herbivores have larger digastricus, pterygoids and masseter for grinding food.
List the cavities from cranial to caudal that occur between the nasal cavity and the trachea
Nasal cavity, nasopharynx, intrapharyngeal osteum, larynx, trachea
List the cavities from cranial to caudal that occur between the oral cavity and the oesophagus.
Oral cavity, oropharynx, intrapharyngeal osteum, laryngopharynx, oesophagus.
Which structure is the oropharynx bounded by caudally?
Soft palate
Which structure is the nasopharynx bounded by ventrally?
Soft palate.
Name the three categories of intra-pharyngeal muscles.
- Dilating
- Constricting
- Shortening
Give three risk factors for periodontal disease development
Any of:
- plaque retentive diet
- concurrent disease such as diabetes, renal disease
- retained deciduous teeth or other teeth crowding
- exposed dentine
- mouth breathing
- xerostermia (oral cavity dryness)
What are the two minimum criteria for PD?
- Presence of a PD pocket colinized by bacteria
2. Active resorption of alveolar bone in presence of acute inflammation (recall that gum recession = bone resorption)
Name three defences of the oral cavity.
Any of:
- normal oral flora
- integrity of oral mucosa
- intra-oral lymphoid aggregations
- salivary contents (peroxidase, lactoferrin, lysozyme, IgA, IgM)
- mechanical disturbance of calculus through mastication
- enamel bulge of tooth
- smoothness of enamel
An animal laying on its right is in ______ recumbency?
Right lateral recumbency.
A radiograph taken of an animal laying on its back is known as a _____ projection?
Ventrodorsal projection - “VD”
Fluid is ____ on xray and ___ on ultrasound. Which is the better medium for observing fluid compared to soft tissue?
Fluid is grey on xray and black on ultrasound. Ultrasound allows distinction of fluid and soft tissue.
What angle should the normal stomach sit at in xray?
Angle of the ribs, roughly.
Why should animals be fasted prior to ultrasound?
Because shadows of ingesta can interfere with the findings.
Define calculus
Mineralised plaque present on both the crown and root of the tooth. The minerals come from the animal’s own saliva.
Define tartar.
Mineralised plaque present on the crown only.
Describe feline odontoclastic resorptive lesions (FORL)
Progressive resorption of the tooth beginning at the cemento-enamel junction mediated by odontoclasts. May occur with or without PD. Clinical signs include anorexia, lethargy, depression, halitosis, dysphagia, may have poor coat.
Give two hypothesised causes for FORL.
- Feline calicivirus infection
2. Chronic regurgitation
The maximum depth for the gingival sulci in health is:
Cats ___ mm
Dogs ___ mm
Cats = up to 1 mm Dogs = up to 3mm
Why is a retained deciduous tooth a risk to the animal’s dental health?
Because it shares a gingival cuff with its permanent counterpart, widening the possible entry route for bacteria into the tooth sulcus.
Give three possible causes of xerostermia (clinically significant reduction in saliva production)
- Malocclusion
- Dehydration
- Chronic renal disease
Also
- diabetes
- hypertension
- autoimmune disease
Crevicular fluid formation is proportionate to ____?
Crevicular fluid formation is proportionate to accumulation of plaque on the tooth.
Give two contents of crevicular fluid.
- IgA, IgM, IgG
- Macrophages
also
- lymphocytes
True or false: crevicular fluid may contribute to pathological inflammation associated with PD?
True. Crevicular fluid plays a defense role before PD is established, but may perpetuate inflammatory damage once PD has begun.
Why does plaque formation progress more rapidly during sleep?
Relative anaerobic conditions inside the oral cavity during sleep assist in growth of pathological gram negative bacterial species associated with PD
True or false - caries have been reported in all domestic species.
False - cats do not have flat occlusal surfaces and so caries are extremely rare/not seen.
Dentine is continually produced over time to protect the pulp cavity. The resulting effect on the pulp cavity is what?
Narrowing of the pulp cavity.
Name the four tissue types involved in periodontitis.
Gingiva, periodontal ligament, cementum and alveolar bone.
True or false - the pellicle normally contains bacteria.
False. However, bacteria may use it as an attachment site in the early stages of periodontitis.