GI Phys 2: Mouth & Esophagus

Question 1

2 types of saliva

Answer 1

serous and mucus

Question 2

serous saliva

Answer 2

watery product that contains salivary enzymes such as a amylase

Question 3

mucus saliva

Answer 3

contains water, electrolytes, phospholipids and MUCIN!

Question 4

what is mucin

Answer 4

mucin is a highly gycosylated protein with multiple functions

Question 5

functions of mucin

Answer 5

protective agent that coats the esophagus and oral mucosa

Question 6

primary stimulus for secrition of the acinar cells (salivary secretion) is what

Answer 6

Ach

Question 7

salivary secretion is regualted by what input

Answer 7

neuronal input

Question 8

how does Ach promote secretion of enzymes and fluid

Answer 8

regulates secretory vesicles and chloride ion channels

Question 9

the fluid secreted into the lumen of the acinar cell is ____

Answer 9

isotonic. however, the tonicity will change as the fluid moves through the duct.

Question 10

salivary glands secrete what type of solution

Answer 10

hypotonic

Question 11

how does the change in tonicity occur

Answer 11

reabsorption of NaCl and secretion of KHCO3 (bicarb)

Question 12

why is water retained in the lumen of the duct

Answer 12

because the ductal cells express tight junction proteins that decrease the permeability of water

Question 13

function of a amylase

Answer 13

starch digestion (carb digestion starts in the mouth)

Question 14

function of mucin

Answer 14

lubrication and protection of oral and esophageal mucosa

Question 15

bicarb (hco3) function

Answer 15

neutralize gastric acid reflux

Question 16

impaired salivary secretions can lead to

Answer 16

increased risk of oral incfection and ulcers

Question 17

what stimulates salviary secretion

Answer 17

Ach!

Question 18

upper 1/3 of esophagus is regulated by what type of muscle

Answer 18

striated. conscious. lower 2/3 is smooth muscle. both from vagal afferents!!!

Question 19

peristaltic activity of the esophagus

Answer 19

no mixing. role of esophagus is to deliver food from mouth to stomach.

Question 20

primary peristalis

Answer 20

inititated with swalowing and will move contents from mouth to stomach

Question 21

if primary peristaltic wave is not enough, what happens?

Answer 21

secondary peristaltic wave is stimulated and starts at the site of the bolus until the food is moved into the stomach

Question 22

what nerve mediates the primary peristaltic wave

Answer 22

vagus

Question 23

contraction vs relaxation of esophagus: what NT’s

Answer 23

Ach = contraction
NO = relxation

Question 24

secondary peristalis is mediated by what

Answer 24

ENS!!

Question 25

causes of GERD (5)

Answer 25

1) delayed gastric emptying 2) increased frequency of transient LES relxations 3) increased acidity 4) loss of secondary peristalsis following transient LES relxation 5) decreased LES tone

Question 26

define LES

Answer 26

lower esophageal sphincter

Question 27

Barrett's esophagus

Answer 27

characterized by the replacement of squamous epithelias cells with columnar epithelias cells giving the epithelial surface a dark red appearance. normal epithelium is light pink. increased risk of esophageal cancer