Mouth and Esophagus

Question 1

most pathology of the esophagus involves…

Answer 1

dysfunctional motility

Question 2

contents of saliva are…

Answer 2

a-amylase, lingual lipase, DNase, RNase, peroxidase, lysozyme, mucous

Question 3

saliva is ….. when it is produced and ….. when it is secreted

Answer 3

isotonic, hypotonic

Question 4

generally, NaCl is exchanged for …. in the salivary duct

Answer 4

KHCO3

Question 5

the degree of modification depends on the …

Answer 5

rate of flow

Question 6

high flow means the solution is hypotonic or isotonic?

Answer 6

isotonic

Question 7

salivary response is affected by the neural system or the endocrine system?

Answer 7

neural system

Question 8

sympathetic stimulation of the salivary glands produces?

Answer 8

a high volume protein poor saliva and a transient, low volume, protein rich saliva (but via different pathways)

Question 9

esophageal peristalsis is coordinated in the…

Answer 9

medulla

Question 10

What are the modulators of UES and LES relaxation?

Answer 10

the vagus nerve for the UES (reflexive relaxation)

NO and VIP for LES

Question 11

primary swallow

Answer 11

initiated either at higher centers (voluntarily) or by pharyngeal mechanoreceptors that sense stretch, but this still requires the extrinsic nervous system

Question 12

secondary swallow

Answer 12

distension in the esophagus triggers a wave that can originate from the site of the blockage, but often triggers a complete swallow due to afferent signals to the medulla

Question 13

Components of the swallowing center

Answer 13

nucleus ambiguus, dorsal motor nucleus, nonvagal nuclei

1) ambiguus - skeletal
2) dorsal motor nuclei - smooth
3) nonvagal - pharyngeal muscles

Question 14

LES relaxation is achieved by?

Answer 14

NO and VIP and they are released from the intrinsic nervous system

Question 15

achalasia

Answer 15

failure of the LES to open

Question 16

diffuse spasm

Answer 16

uncoordinated spasm of the esophageal muscles

Question 17

GERD

Answer 17

chronic acid reflux (with bile) can cause pre-cancer called Barrett’s esophagus

Question 18

Neurodegenerative disease

Answer 18

no normal esophageal motility is possible

Question 19

Intrinsic factor is necessary for the absorption of….

Answer 19

B12

Question 20

Players in parietal cell secretion of HCl

Answer 20

Na/K ATPase, K leak, aquaporins, carbonic anhydrase, Cl/HCO3 antiport, CFTR (Cl leak), H+/K+ ATPase

Question 21

proton pump (H/K ATPase) is sequestered in…

Answer 21

tubulovesicles when not needed (constitutively active)

Question 22

stimulators of acid secretion

Answer 22

Gs (beta1) histamine (H2) -> cAMP
Gq (alpha) gastrin -> PKC
Gi (cholinergic) ACh -> PKC

Question 23

Three ways ACh makes parietal cells secrete HCl

Answer 23

G cells (of antrum) to secrete gastrin, ECL cells to secrete histamine, directly on parietal cells to activate tubulovesicular binding to apical surface

most important player is the stimulation of histamine on ECL cells, which explains the H2 blockers

Question 24

acid secretion phase 1 is called; what happens then?; activation is achieved by?

Answer 24

cephalic phase; ACh release triggers ECL, parietal and G cells, as well as GRP release which further affects G cells; 30% of acid secretion; vagus

Question 25

acid secretion phase 2 is called?; activated by?; what happens then?

Answer 25

gastric phase; activated by distention and some digested amino acids/peptides; further stimulation of acid release (60% of total); vago-vagal reflex; peptides and aminos probably act directly on G cells

Question 26

acid secretion phase 3 is called?; what is released?;

Answer 26

intestinal phase (10%); enterooxyntin is released by distension of duodenum

Question 27

rate of acid secretion peaks how long after a meal?

Answer 27

1 hour

Question 28

somatostatin function/targets?

Answer 28

blocks the pathways that initiate HCl release from parietal cells; namely by blocking G cell release of gastrin and ECL release of histamine but also directly affects parietal cells inhibiting H release

Question 29

threshold for D cell release of somatostatin

Answer 29

ph<4.5

Question 30

principle digestive enzyme in the stomach is…

Answer 30

pepsin

Question 31

pepsinogen release is stimulated by…

pepsinogen is modified by…

Answer 31

ACh during cephalic and gastric phases

H+ nonenzymatically

Question 32

the difference between surface and neck mucous cells is the…

Answer 32

type of mucous they secrete; neck cells secrete soluble mucous that is designed to line the bolus of food; surface cells secrete insoluble mucus that is designed to protect the epithelium from the low pH of the stomach’s lumen

Question 33

breakdown of the insoluble mucous layer causes…

Answer 33

ulcers

Question 34

digestion can be achieved solely by the small intestine or the stomach?

Answer 34

small intestine

Question 35

digestion in the stomach consists of?

Answer 35

linguinal lipases, pepsin

Question 36

lipids and proteins in the stomach play a role in…

Answer 36

signalling, specifically gastrin secretion and pancreatic secretion

Question 37

three main roles of the stomach

Answer 37

relaxing reservoir, grinder, regulating pump for entry into the small intestine

Question 38

receptive relaxation is triggered by… signals are?

Answer 38

mechanostretch receptors that trigger a vago-vagal release of NO and VIP

Question 39

antral systole is…

and the effect of it is…

Answer 39

the effect of two contractile waves pushing the bolus toward the pylorus and the effect is to mix the food with the digestive enzymes thus creating chyme

Question 40

sensation of the rate of stomach emptying is carried out by…
they can affect?

Answer 40

intrinsic sensors of components of the chyme (fats, peptides, acids and hypertonicity); and by duodenal chemoreceptors
they affect the force and rate of gastric contractions

Question 41

four factors that reduce the rate of gastric emptying are?

Answer 41

CCK, secretin, gastrin and an unknown