Physiology 3b: Salivary Excretions, Swallowing, and Esophagus

1) Digestion 2) Lubrication 3) Protection

Starts digestion of: 1) Starches 2) Fats

Facilitates swallowing

Antibacterial properties

1) Parotid 2) Submaxillary/submandibular 3) Sublingual

submaxillary>parotid>sublingual

1) Acinus 2) Intercalated duct 3) Striated duct 4) Myoepithelial cells

1) Blind end of each duct 2) Lined with acinar cells that secrete initial saliva

Connects acinus with striated duct

Modifies inorganic composition of saliva

1) In acinus and intercalated duct 2) Specialized contractile cells 3) Contracts when saliva production is stimulated 4) Ejects saliva into mouth

1) Total ANS 2) Both Parasypathetic and Sympathetic nerves increase saliva production 3) Parasympathetic system provides stronger input

1) Increases transport processes of: A) Acinar B) Ductal cells 2) Stimulates vasodilation of blood vessels

1) Transiently increases production of: A) Saliva and B) Growth of salivary glands 2) Causes contraction of myoepithelial cells 3) Causes constriction of blood vessels

Causes glands to atrophy

Has little effect on glands

1) Food in mouth 2) Smells 3) Conditioned reflexes 4) Nausea

1) Sleep 2) Fatigue 3) Dehydration 4) Fear 5) Anticholinergic drugs

1) Inhibit parasympathetic nerve activity by blocking acetylcholine receptors 2) Examples: A) Benadryl B) Dramamine C) Antidepressants

1) Water 2) Electrolytes 3) Organic compounds

1) Proteins 2) Bacteriocidal substances

1) α-amylase 2) Lingual lipase 3) Mucin

1) Digests starches 2) Found in saliva

1) Digests fats 2) Found in saliva

1) Lubricates food 2) Protects oral mucosa 3) Found in saliva

1) Initial fluid produced is isotonic to plasma 2) Striated ducts modify ionic composition of fluid 3) Flow rate affects [ions]

1) Saliva ultrafiltrate of plasma 2) Hypotonic to plasma

1) Reabsorb Na+ and Cl- 2) Secrete K+ and HCO3- 3) Relatively impermeable to H2O 4) More solute than H2O is reabsorbed 5) Saliva becomes hypotonic

1) Cl- exchanged for HCO3- 2) Na+ exchanged for H+ 3) H+ exchanged for K+

1) At higher rates there is less time for reabsorption to occur 2) Saliva more isotonic; increased A) Na+ B) Cl- C) HCO3-

HCO3- secretion is stimulated when salivation is stimulated

1) Dry mouth 2) Lack of salivary secretion 3) Associated with: A) Cavities B) Chronic infections of buccal mucosa C) Dysfunction of: i) speech ii) taste iii) swallowing

1) Disease that affects salivary glands 2) Causes xerostomia

1) Anticholinergics (e.g. antidepressants) 2) Sjögren's Syndrome 3) Radiation therapy

1) Sipping water 2) Lemon-flavored lozenges 3) Artificial saliva 4) Pilocarpine mouthwashes and tablets

Increases

Increases

Initially decreases, then plateaus

Initially increases, then plateaus

1) Oral phase 2) Pharyngeal phase

1) Voluntary 2) Initiated by: A) Collecting bolus of food B)
Forcing it into oropharynx by pushing up and back against the hard palate

1) Involuntary 2) Nasopharynx closed by soft palate 3) Breathing inhibited 4) Laryngeal muscles contract to: A) Close glottis B) Elevate larynx 5) Peristalsis begins in pharynx to propel food toward esophagus 6) Upper esophageal sphincter relaxes, 7) Allows contraction of constrictor muscles in pharynx to move material into esophagus

1) Coordinated in swallowing center of medulla 2) Initiated voluntarily, but requires something to trigger swallowing reflex 3) Lesions in swallowing center result in loss of pharyngeal phase

1) Difficulty swallowing 2) Caused by: A) Neurological disorders B) Inflammation C) Cancer of: i) mouth ii) throat iii) esophagus

1) Muscle A) Upper 1/3 striated B) Lower 1/2 smooth C) Gradient of striated to smooth in between 2) Upper esophageal sphincter 3) Lower esophageal sphincter

1) UES 2) Formed by cricopharyngeal muscle 3) Separates esophaus from oral cavity 4) Prevents entry of air

1) LES 2) Separates esophagus from stomach 3) Prevents entry of gastric acid 4) Not distinct muscle; thickening of esophagus and increased pressure

1) UES relaxes to permit bolus entry 2) UES contracts to prevent bolus reflux 3) Primary peristaltic contraction (PPC) begins 4) PPC move down esophagus, propelling food to LES 5) LES relaxes 6) Bolus enters stomach 7) LES contracts, preventing acid reflux 8) Secondary peristaltic contraction (SPC) begins and continue until esophagus empty 9) Gravity assists faster motility in upright position

1) Creates zone of increased pressure behind bolus 2) Initiated by swallowing

Initiated by presence of food in esophagus, which stretches mechanical receptors

1) GERD 2) Decreased tone of LES 3) Reflux of stomach acid 4) Causes A) Heartburn B) Esophagitis C) Ulceration D) Stricture due to scaring 5) Treatment: A) Lifestyle changes B) Medications C) Surgery D) Endoscopy

1) LES and part of stomach move up 2) Acid reflux barrier weakened

1) Opening through which esophagus passes through diaphragm 2) Normally aligned with LES

1) Constant esophageal injury (e.g. acid exposure) causes continuous cell growth 2) If left untreated can lead to esophageal cancer

1) Neuromuscular disorder of lower 2/3 of esophagus 2) Absence of peristalsis and failure of LES to relax 3) Food accumulates in esophagus, taking hours to enter stomach 4) Causing dilation of esophagus 5) Patients experience: A) Dysphagia B) Regurgitation of ingested food C) Weight loss 6) Treated with: A) Drugs B) Endoscopic procedures C) Surgery to relax LES

1) Eructation 2) Caused by: A) Air swallowed (aerophagia) B) Gas from heavy meal C) Carbonated beverage, forms bubble in stomach 3) LES relaxes during swallowing process 4) Allows air/gas to enter esophagus
and be regurgitated