saliva, swallowing and esophagus Flashcards

1
Q

list the major pairs of salivary glands in dogs and cats

A
  • parotid
  • zygomatic
  • mandibular
  • sublingual
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2
Q

label the salivary glands in different species

A
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3
Q
A
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4
Q

discuss the composition of saliva

A
  • 98-99% water
  • electrolytes
  • proteins
  • carbohydrate splitting enzyme (amylase)
  • desquamated cells from mucosa
  • lymphocytes
  • mucin if mucus secreting gland
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5
Q

primary saliva secretions are made by what cells where

A

epithelial cells within the acini

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6
Q

discuss modification of saliva

A
  • primary secretion leaves acini
  • modified in ducts
  • Na and Cl gets resorbed
  • HCO3 and K secreted
  • osmolarity depends on flow – faster flow = less time in ducts = less modification = hypertonic vice versa
  • ruminants retain a lot more bicarb to act as buffer in the rumen
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7
Q

this is a salivary gland. what do the arrows indicate

A
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8
Q

Describe basal striation of the striated duct and its other components in the salivary gland

A
  • infolding of the basal cell membrane -> high surface area
  • many mitochondria
  • Na/K-ATPase pump
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9
Q

list salivon cell types and what they produce

A
  • serous cells = watery secretion
  • mucous cells - mucous secretion
  • plasma cells = around the acini and produce IgA to control bacteria
  • myoepithelial cells = envelop each acinus
  • intercalated ducts = secrete HCO3- and absorb Cl
  • striated ducts = secrete K and HCO3- and absorb Na
  • secretory ducts = convey saliva to the mouth
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10
Q

the parotid gland produces what variation of saliva

A

serous in most species but mucus in dogs

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11
Q

the madibular gland prduces which variation of saliva

A

mixed serous and mucus except in rodents (serous)

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12
Q

the sublingual gland produces which variation of saliva

A

mixed except in rodents mucus only

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13
Q

what stimuli encourages saliva production

A

neural and hormonal stimuli

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14
Q

list functions of saliva

A
  • wetting agent/lubricant (eases chewing and swallowing)
  • lubricates oral mucosa (wash teeth remove debris, protect vfrom microbes, antifungal/viral)
  • water soluble food components dissolve in saliva (enhances flavour)
  • enzyme action to aid carb digestion
  • buffering (bicarb regulates acidity in rumen AND keeps oral pH)
  • phosphate buffer
  • hydroxyapatite produces calcium ions
  • urea/ammonia in ruminant for protein recycling
  • anti foaming
  • reoxide antibac
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15
Q

why is salivary bicarbonate important

A
  • in ruminants needed to regulate rumen acidity
  • keeps oral pH in dogs/cats at 7.5, if pH gets too low teeth dissolve and if too high calculus forms
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16
Q

discuss how saliva secretion is regulated

A
  • Sympathetic NS: viscous, amylase, more protein, low volume
  • Parasympathetic NS: water, high volume, increase flow in response to taste, visual and olfactory stimuli, continuous basal flow
17
Q

in ruminants, what stimulates salivation reflex

A

presence of long fibre in the reticulum near the cardia

18
Q

discuss ANS nerve supply of salivation

A
  • sympathetic supply reaches the glands via the arterial supplies
  • parasypathetic travels along the trigeminal nerves, even though the nuclei are linked with facial and glossopharyngeal
19
Q

what are the main salivary glands

A
  • parotid
  • mandibular
  • sublingual
  • zygomatic
  • buccal
  • palatine
  • gustatory (on the tongue)
20
Q

what structures are the arrows pointing to

A
21
Q

describe the parotid gland and duct

A
  • ventral to base of ear
  • V shaped in carnivores to fit arround auricular cartilage
  • C shaped in herbivores and fits against caudal border of the mandibular vertical ramus
  • mixed mucus/serous saliva
  • single duct
  • duct runs from craniomedial surface of the gland across the masseter muscle or ventral to it (cow, horse, pig)
  • opens in the upper buccal area by the maxillary fourth premolar
22
Q

which species have a zygomatic gland and what is it referred to in other animals

A

dogs and cats
- dorsal buccal gland in other mammals (horses)

23
Q

describe the zygomatic gland

A

in rostral portion of the pterygopalatine fossa on the floor of the orbit ventral to the eye, medially to the zygomatic arch and dorsolateral to the last maxillary tooth
- duct opens in upper bucal mucosa opposite the upper first molar or caudal to it
- duct is usuallt caudal to the parotid duct opening and may have several minor openings of the same gland nearby
- often seen as a ridge with several small red dots

24
Q

describe the sublingual glands

A
  • have a polystomatic (many holes) part and a monostatic (one hole) part
  • the monostatic part has a long sublingual salivary duct which runs next to the mandibular salivary duct and opens with it at the sublingual caruncle. the MS part can undergo cystic change
  • in dogs, the polystomatic portion comprises 6-12 lobules with independent short salivary ducts opening sublingually near the frenulum. mucus mainly with lesser serous component
25
Q

discuss the mandibular glands

A
  • slightly cauda and medial to the angle of the mandible limited by the linguofacial vein ventrally and the maxilary vein caudally
  • connective tissue capsule is shared with the monosomatic portion of the sublingual gland
  • the mandibular salivary duct opens at the bulingual papilla (caruncle) at base of the lingual frenulum
  • in about 30% of dogs, the madibular and sublingual ducts merge
  • mixed serous and mucus but can alternate
  • can undergo cyctic change (surgery)
26
Q

what is the hyoid and list the bones

A
  • supports larynx from the skull
27
Q

what is prehension

A

ability to take food into the mouth

28
Q

what nerves give sensory supply to the mouth

A

touch:
- lower jaw/tongue/gingiva/buccal mucosa/teeth = trigeminal (mandibular branch)
- upper jaw/gingiva/mucosa/teeth = trigeminal (maxillary)
- pharynx/larynx = glossopharyngeal and vagus

taste:
- rostral 2/3 of tongue = facial
- caudal 1/3 of tongue = glossopharyngeal
- caudal pharynx and larynx = vagus

29
Q

what i the motor nerve supply to the mouth

A
  • masticatory muscles = trigeminal (mandibular)
  • jaw opening = mandibilar trigeminal and facial
  • swallowing = glossopharyngeal and vagus
  • intrinsic tongue = hypoglossal
30
Q

why are mammals able to chew and breath at the same time

A

presence of hard palate

31
Q

what are the 3 seals of the mouth

A

Lips
Tongue against soft palate
Soft palate against epiglottis

32
Q

describe the 3 stages of swallowing

A

1st stage:
- tongue moves food around
- masticated food + saliva -> bolus
- up and back between fauces to pharynx

2nd stage:
- soft palate elevated -> closes posterior nares
- epiglottis covers larynx and trachea (breathing suspended)

3rd stage:
- oesophagus dilates
- bolus passes up and over larynx into oesophagus
- oesophagus recloses and epiglottis uncovers trachea
- bolus moves down oesophagus into stomach

33
Q

Describe what is different about the mouth anatomy of chinchillas and guinea pigs and its clinical relevance`

A

Palatal ostium:
soft palate almost seals off the oropharynx from the naso and laryngopharynx
small hole (ostium) remains
This makes intubation almost impossible