Mouth and esophagus Flashcards
What is the function of saliva relating to the oral mucosa?
Keeps it hydrated
What is the function of saliva in mastication?
Lubrication and swallowing
What is the function of saliva in the immune system?
Kills bacteria
What is the function of the saliva in protecting the teeth?
Neutralize gastric acid
What is the major enzyme found in the saliva?
Alpha-amylase
What does the mucus of saliva contain?
Water
Electrolytes
phospholipids
MUCIN
What is mucin?
Highly glycosylated protein with multiple functions throughout the GI system, but coats and protects the lining of the GI tract
What is the ion that promotes fluid secretion in the salivary glands when Ach attaches to its muscarinic factor on salivary glands?
Ca release
What is the ion that is secreted into saliva that causes water to follow?
Cl
What happens to the presaliva as it moves from the salivary duct lumen to through the duct (as far as dissolved solutes go0?
Goes from isotonic to hypotonic
What is the pH of saliva? How does it get there?
8–secretion of HCO3 in the duct of the salivary glands
What are the two ions that are reabsorbed from the salivary duct? What is secreted?
Na
Cl
HCO3, K are secreted
What is the specialization of the ductal cells that prevents water reabsorption when Na and Cl are reabsorbed?
tight junctions
What is the neurotransmitter and ion that is needed to release vesicles into the salivary ductal lumen?
Ach and Ca
What is the effect of anticholinergic drugs on salivary glands?
Inhibits release of saliva (dry mouth)
What is the function of alpha amylase in salive?
Starch digestion
What is the Ig that is released in saliva?
IgA
What is the function of lingual lipase in saliva?
Fat digestion
What is the function of mucin in the saliva?
Lube and protection
What is the function of Na, K, Cl, HCO3, H2O in saliva?
Alkalinization and HCO3
What is the function of water in saliva?
Taste, swallowing, and speech
What is the type of innervation in the upper third? Lower 2/3?
upper 1/3 = somatic
Autonomic for the rest
What are the three phases of esophageal motor activity (swallowing)?
Oral phase
Pharyngeal phase
Esophageal phase
What happens to the soft palate during the pharyngeal phase of swallowing?
Pulled downward to prevent reflux into the nasopharynx
What happens to the the larynx and vocal cords during the pharyngeal phase of swallowing?
move upward
What happens to the epiglottis during the pharyngeal phase of swallowing?
Swings down
What happens in the esophageal phase of swallowing?
The upper esophageal sphincter contracts and the primary peristaltic wave moves the bolus of food toward the stomach
What happens if the first peristaltic wave is insufficient?
Second wave initiated
What is the effect of distention/ low pH on sensory neurons in peristalsis?
Stimulates secondary peristalsis via recruitment of Ach upstream, and NO/VIP downstream
What are the 5 causes of GERD?
- Delayed gastric emptying
- Increased frequency of transient LES relaxations
- Decreased pH
- Loss of secondary peristalsis following transient LES relaxation
- Decreased LES tone
What is the vicious cycle of recurrent injury in GERD?
Scarring, leading to further incompetent LES
What is the primary neurotransmitter responsible for LES relaxation?
NO or VIP
What is Barrett’s esophagus?
transition from stratified squamous epithelium of the esophagus, to pseudostratified columnar with goblet cells in the lower esophagus
What is the effect of benzodiazepines on GERD?
relaxes LES
What is the impact of smoking on GERD (3, maybe)?
Increased acid secretion
Decreased LES tone
Decreased salivation
Ninety percent of the saliva is produced from which three glands?
Parotid
Submandibular
Sublingual
The initial secretion of water into the lumen of a salivary gland is mediated by what neurotransmitter? What type of receptor does this activate?
Ach–Muscarinic
Although norepinephrine stimulates the secretion of fluid and enzymes, norepinephrine also does what?
decreases blood flow to the salivary glands (as previously discussed) which causes a net reduction in salivary secretion.
What happens in the pharyngeal phase of swallowing?
The upper esophageal sphincter (UES) relaxes and the bolus of food moves deeper into the pharynx. Peristaltic contractions are initiated.
Motor activity of the esophagus is regulated by what nerve inputs onto both smooth and striated muscle?
vagus
Mechanical dysphagia can be caused by what? (3)
Reflux disease; alcohol and tobacco use; and viral infections caused by the human papilloma virus (HPV)
Functional dysphagia may result from what (2)?
disruption of striated muscle or a neuronal disorder.
What is achalasia?
Achalasia is a result of denervation of esophageal smooth muscle and impaired function of the lower esophageal sphincter
What are sliding hiatal hernias?
the stomach slides into the thoracic cavity through the esophageal hiatus
What are the symptoms of sliding hiatal hernias?
reflux of gastric contents into the esophagus
What is a paraesophageal hiatal hernia?
the greater curvature of the stomach protrudes through an opening or tear in the diaphragm
What happens to the salivary glands in CF patients?
Become clogged and fibrotic d/t malfunction of Cl transporter
What is the pathophysiology of Sjögren syndrome?
Autoimmune attack against the CFTR protein in salivary glands
What type of receptor is between the pre and postganglionic neurons that connect the vagus to the parietal cells? What is the possible effect of smoking on this?
Ach-nicotinic receptor. Thus smoking could potentially increase acid secretion
What is the effect of substance P and NE on saliva production?
Both increase, but NE also decreases blood flow to the salivary glands, thus in the end reducing secretions
