3. Salivary Glands

Question 1

Salivary glands in the dog

Answer 1

parotid, mandibular, sublingual

Question 2

Salivary glands in the horse

Answer 2

buccal, parotid

Question 3

Types of saliva

Answer 3

Serous - parotid, high in amylase (pig)
Mucus - buccal
Both - submandibular, sublingual

Question 4

Composition of saliva

Answer 4

Mucus, water, electrolytes
High in bicarb/urea (ruminants)
High in Ca+ (horse)
High volume in herbivores

Question 5

Functions of saliva

Answer 5

• soften and lubricates ingesta
• evaporative cooling in dog/cat
• buffering for fore stomach digestion
• starch/fat digestion (minor)

Question 6

Importance of ducts

Answer 6

Anatomy analogous to glomerulus and collecting ducts = means of modifying primary secretion at slow rates of flow

• ion transporters (exchange of Na for H/K ions, reabsorption of NaCL)
• respond to aldosterone

Question 7

Isotonic vs. isosmotic

Answer 7

isotonic = concentration of salts in solution, same as in cells
isosmotic = concentration of salts in solution, same as other solutions (body fluids)

Question 8

Non-ruminant vs. ruminant primary vs. final secretion

Answer 8

Non-ruminant: isotonic initial secretion, followed by a hypotonic secretion
Ruminant: saliva remains isotonic throughout regardless of saliva flow

Question 9

Stimulation of secretion

Answer 9

• ANS: cholinergic stim. increases flow rate
• Pavlov response in dogs
• Mastication in horses (parotid)
• Mechanical stimuli in horses and ruminants: NG/OG tube

Question 10

Inhibition of secretion (ruminants)

Answer 10

Rumen distention

Question 11

Continuous secretion: species and gland (2)

Answer 11

Cat: sublingual
Ruminant: parotid

Question 12

Cause of urolithiasis in male castrated goats

Answer 12

High grain, low roughage diets = high P:Ca ratio

• decreases formation of saliva, so P cannot be excreted via saliva
• P excreted via urina instead = alkaline urine = uroliths
• **forage based diets increase saliva production, recycle P through saliva, excrete via feces

Question 13

What is a clinical application of mastication induced flow from parotid salivary gland in horses?

Answer 13

Can be used to detect flow from a wound in that area - is the duct damaged?
- saliva is high in Ca+ = chalky residue

Question 14

UES anatomy

Answer 14

cricopharyngeus muscle

Question 15

Esophageal body anatomy

Answer 15

striated and smooth muscle, distribution depending on species

Question 16

LES anatomy

Answer 16

functional sphincter

Question 17

What might account for poor healing in the esophagus?

Answer 17

only the short abdominal segment has serosal covering

Question 18

Esophageal mucosa anatomy

Answer 18

White, composed of squamous epithelium arranged in longitudinal folds that flatten to accommodate bolus

Question 19

Muscle distribution of esophagus (species differences)

Answer 19

Dog, ruminants, pig: all striated along body

Horse (2/1), cat (1/1): proximal striated, distal smooth

Question 20

Motility in the esophagus is ____

Answer 20

peristaltic: propagating ring of contraction that travels aborad
- also orad in ruminants = rumination

Question 21

Primary peristalsis***

Answer 21

Initiated by act of swallowing, traverse whole body length, can be propagated with or without bolus

Question 22

Secondary peristalsis***

Answer 22

Initiated by presence of contents anywhere along the body, not by swallow (different neural control)
Occurs if primary contraction fails to empty esophagus or when gastric contents reflexed

Question 23

Control of esophageal function/motility

Answer 23

• pharyngeal component of deglutition is voluntary = swallowing center
• vagal fibers to striated muscle