HRR: secretions and motility II

Question 1

What is the cephalic phase?

Answer 1

Readies the GI tract for a meal; happens before we even take in food.

Question 2

What happens during the cephalic phase?

Answer 2

Saliva production, PSNS activation enhances secretions and gall bladder contraction.

Question 3

Salivary glands are innervated by…

Answer 3

Maxillary, facial, and glossopharyngeal nerves.

Question 4

What is the oral phase?

Answer 4

We had taken in food; breaks up food to increase surface area with digestive enzymes.

Question 5

What are the main enzymes in saliva?

Answer 5

Salivary amylase and lingual lipase.

Question 6

What muscles are used in chewing?

Answer 6

Masseter, temporalis, medial and lateral pterygoids.

Question 7

What are the 3 big salivary glands?

Answer 7

Parotid, submandibular, sublingual.

Question 8

Describe PSNS innervation of the parotid gland.

Answer 8

1. Preganglionic fibers from cranial nerve 9 (glossopharyngeal nerve) synapse at the otic ganglion.
2. The postganglionic fibers merge with the auriculotemporal branch of nerve 5 (trigeminal) to stimulate the parotid gland via ACh.

Question 9

Describe the PSNS innervation of submandibular and sublingual glands.

Answer 9

1. Preganglionic fibers from cranial nerve 7 (facial nerve) travel via chorda tympani to the submandibular ganglion.
2. The postganglionic fibers merge with the lingual nerve from cranial nerve 5 (trigeminal) to stimulate the glands via ACh.

Question 10

Describe sympathetic innervation of salivary glands.

Answer 10

1. Preganglionic fibers from the spinal cord synapse in the superior cervical sympathetic ganglion
2. postganglionic fibers travel via adjacent nerves and vessels to stimulate the glands via norepinephrine.

Question 11

Which is responsible for protein/enzyme secretion and production: PSNS OR SNS?

Answer 11

SNS.

Question 12

The parotid gland has ___ secretion.

Answer 12

Serous.

Question 13

The submandibular gland has ___ secretion.

Answer 13

Serous/mucous.

Question 14

The sublingual gland has ___ secretion.

Answer 14

Mucous.

Question 15

What are acinar cells?

Answer 15

Cells that determine secretion type in salivary glands. They’re the ‘end pieces’ in the structure of glands and are stimulated by ACh and substance P.

Question 16

Describe movement of salivary fluid starting at acini.

Answer 16

Acini, intercalated ducts, striated ducts, excretory ducts, single large duct taking saliva to the mouth.

Question 17

Acinar cells make __ secretion.

Answer 17

Primary.

Question 18

Ductal cells make ___ secretion.

Answer 18

Secondary (modified).

Question 19

Describe the contents of saliva.

Answer 19

Water, potassium, bicarb, sodium, digestive enzymes. Generally hypotonic.

Question 20

What is primary secretion?

Answer 20

The fluid produced by acinar cells that is high in amylase, mucin, potassium, bicarb, sodium, chloride, and water.

Question 21

Describe how acinar cells secrete fluid.

Answer 21

1. ACh binds to a receptor on the basolateral membrane, increasing intracellular calcium
2. This drives the sodium potassium pump, removing sodium from the cell.
3. The NCCK2 pump then brings in sodium, chloride, and potassium.
4. The sodium, chloride, and bicarb will leave the cell on the luminal side, bringing water with them through leaky tight junctions.

Question 22

What is secondary secretion?

Answer 22

Striated ducts reabsorb sodium and chloride and secrete more potassium and bicarb, increasing osmolarity to almost isotonic and alkalizing it.

Question 23

Are tight junctions in acinar cells or striated ducts leakier?

Answer 23

Acinar cells.

Question 24

The swallowing center involves which nerves?

Answer 24

Trigeminal, glossopharyngeal, vagus, hypoglossal.

Question 25

The nucleus ambiguous is necessary in the…

Answer 25

Swallowing center.

Question 26

What is inhibited as we swallow?

Answer 26

Respiration and vomiting.

Question 27

Describe the process of swallowing.

Answer 27

1. The tip of the tongue presses against the hard palate to move bolus up and back into the mouth. 2. Bolus enters the pharynx, stimulating touch receptors to initiate swallowing reflex. 3. Soft palate pulls upward, and nasopharynx is blocked via palatopharyngeal folds. This opens a passage to the pharynx. 4. Vocal cords close, and larynx moves forward and up against the epiglottis to prevent aspiration and open upper esophageal sphincter 5. UES relaxes to prepare upper esophagus. 6. Pharyngeal constrictor muscles contract and propel bolus into the upper esophagus.

Question 28

What are the 3 things preventing food from going through the airway?

Answer 28

Closing epiglottis, opening UES, inhibiting respiration.

Question 29

What is the primary job of the esophagus?

Answer 29

Propel food bolus to the stomach via peristalsis.

Question 30

Describe esophageal sphincters at rest.

Answer 30

They are contracted to prevent reflux or regurgitation via tonic contraction through ACh/substance P.

Question 31

What stimulates relaxation of esophageal sphincters?

Answer 31

NO and VIP.

Question 32

Describe the functions of the inner circular layer in the esophagus.

Answer 32

It contracts behind the bolus and relaxes ahead of the bolus to propel it forward.

Question 33

Describe the functions of the outer longitudinal layer in the esophagus.

Answer 33

It relaxes behind and contracts ahead of the bolus to dilate the lumen so it can receive the bolus.

Question 34

Much of peristalsis is regulated by…

Answer 34

The myenteric plexus.

Question 35

What is secondary peristalsis?

Answer 35

Squeezing of the esophagus that does not happen due to ingestion of food but instead happens as a result of distension to clear the esophagus. This could be from retained bolus, refluxed contents, etc.

Question 36

When is receptive relaxation?

Answer 36

The LES opens and the proximal stomach relaxes to accommodate incoming food.

Question 37

What neural processes drive receptive relaxation?

Answer 37

Myenteric inhibitor neurons and vagal relaxation.

Question 38

What is Sjogren’s syndrome?

Answer 38

Autoimmune condition that attacks salivary glands.

Question 39

What is sialolithiasis?

Answer 39

Stone in a duct which causes obstruction, swelling, and pain.

Question 40

How does cystic fibrosis impact saliva?

Answer 40

It will become thick and more mucousy.

Question 41

What is zenker’s diverticulum?

Answer 41

Weakness in the wall of Killian's triangle causing a diverticular outpouching of the upper esophagus.

Question 42

What is achalasia?

Answer 42

LES struggles to relax in response to swallowing. Usually due to myenteric plexus degeneration, specifically inhibitor neurons, causing the tonic contraction to occur constantly.

Question 43

What is the buzzword for achalasia?

Answer 43

Bird-beak appearance.

Question 44

What structures act as a barrier to prevent reflux?

Answer 44

LES, diaphragmatic crura, gastroesophageal flip valve.

Question 45

What is Barrett's esophagus?

Answer 45

A change in the lining of the distal esophagus from stratified squamous to intestinal columnar epithelium via intestinal metaplasia. This happens in response to excessive acid exposure and is supposed to be protective, but predisposes the person to adenocarcinoma.