Digestive System wks 1-3 Flashcards
Which teeth in the dog have three roots?
Upper P4, M1, M2
In what species are “needle teeth” found and what teeth are they?
Pigs. They refer to the 4 third incisors and 4 canines. These teeth are fully erupted deciduous teeth
What is characteristic of hypsodont teeth that differs to brachydont teeth?
Hypsodont teeth continue to grow (from their apical aspect) long after the tooth has erupted. Eruption itself continues for life to compensate for occlusal wear. Brachydont teeth do not continually erupt.
What is the “cup” or “mark”?
Also known as the infundibulum. The space filled with cementum due to folds which form in the cementum during development of the tooth. Known as the mark when we reach the base of it.
What is the “star”?
The pulp cavity in cross section of the tooth. It’s protected by secondary and sometimes tertiary dentine.
At what age do canine teeth appear in horses?
4-6 years. However they only appear in males (in the diastema) and only in some males. They are brachydont teeth.
The wolf tooth is…
The first premolar in horses. Only in 13%-32% and more commonly noted in females
Why do animals with hypsodont teeth have a convoluted enamel pattern on the grinding surface (“table”) of their teeth?
This forms due to the different rates of wear of the materials comprising the tooth. For example, enamel is a much stronger material than dentine or cementum and therefore slows down at a slower rate than them.
What are the ways in which we can assess the age of animals using their dentition?
- Eruption times (eruption of incisors)
- Changes to the incisor occlusal surface (including dental star, dental cup/mark, and changes to the shape of the occlusal surface)
- Shape of the upper corner incisor
- Curvature of dental arch of lower incisors
- Angle of incisors
- Hook present on upper corner incisor
- Galvayne’s groove
What are boundaries of the oral cavity?
Dorsal: hard palate and soft palate Caudal: palatoglossal arches Rostral: lips Ventral: floor of oral cavity Lateral: cheeks
What is the function of the oral cavity?
Prehension of food Mastication Insalivation of food Deglutition Taste Defence/ aggression Grooming Temperature regulation
The epithelium of the oral mucosa has ____________ ______________ ____________ cells.
Stratified squamous epithelial cells
What is the layer of connective tissue directly underlying the external epithelium and making up the oral mucosa?
Lamina propria
What muscles are associated with the oral cavity and what nerve are they innervated by?
Caninus
Levator labii superioris
Depressor labii inferioris (in cat only)
Levator nasolabialis
All innervated by the facial nerve (CN VII)
What is the cleft marking division in the upper lip of dogs, cats, camelids and sheep?
Philtrum
The muscle responsible for returning food from the outer vestibule to the oral cavity is the…
It is innervated by…..
Buccinator
Facial nerve (CN VII)
What are rugae?
Ridges/ folds on the hard palate or stomach
Palatine glands are present in all species except….
Pigs! 🐷🐷🐷
The bones comprising the palate are…
Palatine, maxilla, incisive
The function of the frenulum is to…
Connect the tongue to the floor of the oral cavity.
What are the different forms of papillae?
- Filiform
- Conical
- Fungiform
- Lentiform
- Foliate
- Vallate (circumvallate)
- Marginal papillae (in newborn dog and pig to aid suckling)
Taste buds are clusters of specialised cells located within the epithelium of _________ _________. Nerves responsible conveying sense of taste include the________
Gustatory papillae.
Facial nerve (CN VII) and glossopharyngeal nerve (CN IX)
Muscles supporting the tongue include the…
Extrinsic muscles of the tongue are…
Innervated by…
Mylohyoideus and geniohyoideus.
Styloglossus, hyoglossus and genioglossus.
Hypoglossal nerve (CN XII)
General sensation in the rostral 2/3 of the tongue is innervated by ___________. In the caudal 1/3 it is ________. Taste in the rostral 2/3 is innervated by_______. In the caudal 1/3 it is ________.
Trigeminal-mandibular division of CN V
Glossopharyngeal (CN IX)
Facial nerve (CN VII)
Glossopharyngeal
Muscles of mastication include:
Temporalis, masseter, pterygoids, digastricus
The TMJ is the articulation between….
Zygomatic process of the temporal bone and the condylar process of the mandible.
The three parts of the pharynx are…..
Sensory and motor innervation are provided by…
Oropharynx
Nasopharyngeal
Laryngopharynx
Glossopharyngeal (CN IX) and vagus (CN X)
What does monophyodont mean? Give an example.
Only one set of teeth erupt and remain in function throughout life. There are no deciduous teeth. Includes rodents and dolphins.
What does polyphyodont mean? Example.
Many sets of teeth are continually replaced. Sharks and crocodiles.
What is a diphyodont?
Having two sets of teeth.
What is a characteristic of a brachydont tooth?
Shorter crown:root ratio
What is characteristic of hypsodont teeth?
Dentition has a submerged, longer anatomical or reserve crown and comparatively short roots. They are continually erupting as the crown wears down.
What are radicular and aradicular hypsodont teeth?
Radicular: dentition has true roots and erupts additional crown throughout most of life. They eventually close their root aperture and cease growth.
Aradicular: absence of true roots. Additional crown is produced throughout life. Eg. Incisors of rodents.
A unilateral cleft lip occurs when migration fails to occur between ________ and ________. A bilateral cleft lip occurs when__________.
One of the maxillary process and the medial nasal process.
Both maxillary processes fail to migrate.
What is hertwigs epithelial tooth sheath?
The cervical loop formed by the junction of the outer enamel epithelium and the inner enamel epithelium.
What are some local secondary factors which may influence periodontal disease?
Tooth crowding, mouth breathing, plaque retentive diners, tooth shape
What is the difference between gingivitis and periodontitis?
Gingivitis is the reversible inflammation of the gingiva associated with the plaque. Periodontitis is the irreversible loss of CT attachment with true pocket formation.
What is the minimal definition of periodontitis?
- Presence of PD pocket colonised by bacteria
2. Active resorption of alveolar bone in the presence of acute inflammation.
What is the term for sig loss of salivary volume?
Xerostomia
What is scaling? What is root planing?
Supra and sub-gingival removal or plaque and calculus from tooth surfaces.
Removal of residual calculus and endotoxins affected cementum from the roots
What are 12 steps involved in complete dental treatment?
- Periodontal probing and charting
- Dental radiographs (+/-)
- Recording and development of treatment plan
- Scaling
- Sub-gingival debridement
- +/- gingival surgery and open root planning
- Polishing
- Sulcular lavage
- Antimicrobial treatments
- Advanced perio treatments
- Home care advice/ instructions
- Recall/ review
What is exodontia?
Dental extractions
What are the most common reasons for exodontia?
- Advanced PD
- Crown/ root fractures and subsequent periapical pathology
- TR in cats
- Retained deciduous teeth
- Traumatic occlusion
- Supernumerary teeth
- Dental caries
What is the pellicle?
Protein film that forms on the surface enamel by selectively binding glycoproteins from saliva. This prevents continuous deposition of salivary calcium phosphate and can serve as an attachment medium for bacteria.
What is plaque? What is calculus?
Mass of bacteria firmly adherent to a pellicle. It is a biofilm.
Calculus is mineralised plaque which provides a suitable surface for plaque bacteria to hide and survive.
What are the stages of plaque formation?
- Saliva bathes tooth (attachment of glycoproteins/ mucopolysaccharides)
- Bacterial colonisation (gram +ve) ➡️ migration of organisms into gingival sulcus; metabolic byproducts attract WBCs
- Gram +ve to gram -ve bacteria (2 weeks min)
Association, adhesion, proliferation, micro colonies, biofilm formation, growth/ maturation
What components make up the hyoid apparatus?
Stylohyoid bone, epihyoid, ceratohyoid, basihyoid, epiglottic cartilage, thyroid cartilage, arytenoid cartilage and cricoid cartilage
The large hole on the caudal aspect of the skull if the _______ ________ and it allows passage of what?
Foramen magnum
Spinal cord
Three clinically relevant foramina on the skull are….
Supraorbital foramina (upper eyelid) Mental foramina (rostral mandible) Infraorbital foramina (rostral maxilla)
Describe the three divisions of the temporal bone.
- Petrosal- contains semicircular canals (balance) and the cochlear duct
- Tympanic- tympanic bulla lies beneath the external acoustic meatus.
- Squamous
Describe the anatomy of the tympanic bulla and how air pressure is equalised between the external meatus and the ear drum.
🔹It lies immediately below the external acoustic meatus
🔹a thin tympanic membrane extends across this meatus dividing it from the external ear canal
🔹to the inside of the tympanic membrane, the tympanic bulla contains an air-filled cavity associated with the middle ear and connected to the nasopharynx via an auditory tube (eustachian tube)
🔹 the Eustachian tubes open when there are movements in the soft tissues of this region to equalise air pressure
What are the scrolls of turbinate bone in the nasal passages called? They divide the nasal cavity into ____ passages (meatuses).
Conchae
3
What is the cribiform plate?
Sieve-like structure of the ethmoid bone which allows passage of olfactory nerves between the brain and nasal passages.
The 4 main types of salivary glands are innervated by…
CN VII ( Mandibular, sublingual, buccal and zygomatic) and CN IX (parotid)
Describe the process of deglutition (7 steps)
Bolus prepared by mastication and salivation ➡️ apex of tongue pressed to hard palate ➡️ rapid contraction of mylohyoideus and extrinsic tongue muscles to move bolus into oropharynx ➡️ contact between food bolus and pharyngeal mucosa sets off reflexes ➡️ soft palate is raised, glottis is closed, hyoid apparatus is drawn rostrally, pharynx is shorten (drawn rostrally) ➡️ bolus moves to oesophagus by pharyngeal sphincter ➡️ peristalsis moves bolus to stomach
Describe the path of the oesophagus.
The oesophagus has three segments: the cervical, thoracic and abdominal.
The cervical segment begins dorsal to the cricoid cartilage and follows trachea inclining slightly to the left. It is situated medial to the left jugular groove. At the level of the 1st rib it returns to median position.
The thoracic region is situated within the mediastinum of the thorax. It passes over the base of the ❤️ and crosses the right side of the aortic arch. It continues dorsal to the tracheal bifurcation and goes slightly left before passing ventral to the aorta. It ends at the oesophageal hiatus of the diaphragm.
The abdominal region is the shortest. It passes over the dorsal border of the liver and ends at the cardia.
What is the difference between the adventitia and the serosa?
The adventitia is found around organs outside of the peritoneal cavity, or outside the thorax and abdomen. The CT merges with that of surrounding structures.
Serosa: CT are covered by an epithelial layer
What are possible sites of oesophageal obstructions?
Cranial and caudal regions
Immediately anterior to oesophageal hiatus
Over base of the ❤️
Thoracic inlet
Where do the following glands open:?
- Parotid
- Mandibular
- Sublingual
- Buccal
- Zygomatic
- Outer vestibule (opposite upper P4)
- Sublingual caruncle
- Adjacent to frenulum
- ?????
- Opposite last upper molar
Describe what the following colour changes of the oral mucosa indicate:
- Black
- Yellow
- White
- Blue
- Red
- Brown
- Normal melanin deposition
- Jaundice (icterus)
- Anaemia (⬇️ erythrocytes)
- Cyanosis (inadequate oxidation of blood)
- Inflammation, haemorrhage/ congestion
- Methaemoglobinaemia, porphyria
What is palatoschisis and what is is caused by?
Cleft palate. Caused by failure of the lateral palatine processes of the maxillary bone to close.
What is cheiloschisis and what is it caused by?
Cleft lip/ hare lip
What is the cul-de-sac?
The fundus of the reticulum which is in contact with the diaphragm, liver, omasum and abomasum.
Three internal features of the reticulum include…
- Three openings (cardia, ruminoreticular orifice, reticulo-omasal orifice)
- Reticular groove (medial wall)
- Reticular folds
How many sacs is the rumen demarcated into?
5 (6)
Dorsal, ventral, caudodorsal, caudoventral, cranial, (insula ruminus)
Describe the distribution of papillae within the different sacs of the rumen?
Ventrocaudal and dorsocaudal: long and numerous
Ventral: few and less prominent
Dorsal: short or absent
Three internal features of the reticulum include…
- Three openings (cardia, ruminoreticular orifice, reticulo-omasal orifice)
- Reticular groove (medial wall)
- Reticular folds
What is the blood supply and nerve supply of the compound stomach?
Celiac artery (drains into portal vein) Dorsal and ventral trunk branches of vagus nerve
What is the peritoneum?
Serious membrane lining abdominal cavity and part of the abdominal cavity. Simple squamous mesothelium lying on connective tissue. Parietal and visceral surface. Connecting peritoneum includes mesocolon, mesentery, greater omentum and ligaments.
What is a lyssa?
Rod shaped fibrous body in median plane beneath ventral mucosa of mouth.
Tooth resorptive lesions are most common where?
Mesial premolar teeth
Where does the lesser omentum arise from?
The visceral surface of the liver
Where does the large intestine of the cow lie?
In the supraomental recess with the small intestines
The bovine caecum has a capacity of approximately ___________. Its apex lies to the right of the pelvic inlet and it is separated from the right flank by the ____________.
8 litres
Greater omentum
The transverse colon of the cow passes ___________➡____________ cranial to the _______________.
Right ➡ left
Cranial mesenteric artery
Does the porcine caecum have any taenia/ haustra?
Yes. 3 of each
The ascending colon of the pig forms a cone shaped mass. There are _________ centripetal turns with _____ taenia/haustra. No taenia/ haustra exist on the centrifugal coils.
2-3
2
