Gastric Motility and Pancreatic Function

Question 1

where do the peristaltic waves of the stomach go?

Answer 1

body to antrum

Question 2

what is significant at the fact that the body of the stomach has weak muscle?

Answer 2

weak contrcation means no mixing

Question 3

does the antrum have weak or thick muscle? what does this mean?

Answer 3

Thick muscle = powerful contraction

Mixing

Contraction of pyloric sphincter

Only small quantity of gastric content (chyme) entering duodenum

Further mixing as antral contents forced back towards body

Question 4

what is the peristaltic rhythm generated by?

Answer 4

pacemaker cells (longitudinal muscle layer)

Question 5

what produces a slow wave?

Answer 5

spontaneous depolarisation/repolarisation

Question 6

what determines the strength of contraction of waves?

Answer 6

number of APs

Question 7

does gastrin increase or decrease contraction?

Answer 7

increase

Question 8

does dilation of stomach wall decrease or increase contraction?

Answer 8

increase

Question 9

how does fat/acid/amino acid/hypertonicity in duodenum effect motility?

Answer 9

inhibits

Question 10

where is HCO3 secreted from in the duodenum?

Answer 10

brunners gland duct cells (submucosal glands)

Question 11

acid in duodenum triggers…

Answer 11

Long (vagal) & short (ENS) reflexes HCO3 secretion

Release of secretin from S cells HCO3 secretion

• Secretin HCO3 secretion from pancreas & liver
• Acid neutralisation inhibits secretin release (negative feedback control)

Question 12

what are the three parts of the pancreas?

Answer 12

body, tail, head

Question 13

what is involved in the endocrine portion of the pancreas?

Answer 13

pancreatic islets (islets of Langerhans):

islet cells produce insulin, glucagon (control [glucose]blood ) and somatostatin (controls secretion of insulin and glucagon)

Question 14

what is involved in the exocrine portion of the pancreas?

Answer 14

acinar cells lobules

Question 15

what are lobules connected by?

Answer 15

intercalated ducts

Question 16

where does the secretion of bicarbonate occur?

Answer 16

duct cells

Question 17

where does the secretion of digestive enzymes occur?

Answer 17

acinar cells

Question 18

what do acinar cells contain?

Answer 18

digestive enzymes stored as inactive zymogen granules

Question 19

what is the function of zymogens?

Answer 19

prevents autodigestion of pancreas

Question 20

what converts trypsinogen to trypsin?

Answer 20

enterokinase

Question 21

what converts all other zymogens to active forms?

Answer 21

trypsin

Question 22

what are the categories of pancreatic enzymes?

Answer 22

proteases
nucleases
elastases
phospholipases
lipases
a amylase

Question 23

what is the function of proteases?

Answer 23

Cleave peptide bonds

Question 24

what is the function of nucleases?

Answer 24

Hydrolyse DNA/RNA

Question 25

what is the function of elastases?

Answer 25

Collagen digestion

Question 26

what is the function of phospholipases?

Answer 26

Phospholipids to fatty acids

Question 27

what is the function of lipase?

Answer 27

Triglycerides to fatty acids+ glycerol

Question 28

what is the function of a amylase?

Answer 28

Starch to maltose + glucose

Question 29

bicarbonate secretion stimulated by

Answer 29

secretin

Question 30

secretin released in response to

Answer 30

acid in duodenum

Question 31

zymogen secretion stimulated by

Answer 31

cholecystokinin (CCK)

Question 32

CCK released in response to

Answer 32

fat / amino acid in duodenum