Gastric motility and pancreatic function

Question 1

Gastric motility: wave of movement is called?

Answer 1

peristaltic wave

Question 2

what generates the peristaltic rhythm?

Answer 2

Pacemaker cells in the longitudinal muscle layer in the greater curvature region of the fundus.

Question 3

Describe the antrum of the stomach

Answer 3

bottom end of the stomach

thick muscle, powerful contraction which ensures mixing of contents

Question 4

Contraction of the pyloric sphincter ensures what?

Answer 4

Only a small amount of gastric content (chyme) enters the duodenum

so as the antral contents are forced back towards the body - more mixing occurs

Question 5

Describe the body of the stomach

Answer 5

Thin muscle - weak contraction

No mixing

Question 6

what is another name for the slow wave rhythm

Answer 6

basic electrical rhythm

the spontaneous depolarisation and repolarisation of pacemaker cells in the longitudinal layer

Question 7

Neural/hormonal control of motility

Answer 7

Gastrin - increases contraction

Distension of stomach wall - long/short reflexes - increased contraction

Fat/acid/amino acid/hypertonicity in duodenum - inhibition of motility

Question 8

How is acid neutralised in the duodenum

Answer 8

Bicarbonate (HCO3) secretion from Brunner’s Gland duct cells (submucosal glands)

Question 9

Control of duodenal HCO3 secretion?

Answer 9

Acid in duodenum triggers…

Long (vagal) & short (ENS) reflexes - which increase HCO3 secretion

Release of secretin from S cells - that increase HCO3 secretion

Acid neutralisation - inhibits secretin release (negative feedback control)

Question 10

What are the group of cells called in the pancreas that produce insulin, glucagon and somatostatin?

Answer 10

islets of Langerhans

Question 11

What makes up the endocrine portion of the pancreas?

Answer 11

pancreatic islets/islets of langerhans

Question 12

what makes up the exocrine portion of the pancreas?

Answer 12

acinar cells

lobules

Question 13

what do acinar cells do?

Answer 13

produce and transport enzymes that are passed into the duodenum where they assist in the digestion of food and also HCO3 which acts to neutralise acid entering the duodenum.

Question 14

Describe the structure of a lobule

Answer 14

composed largely of grape-like clusters of exocrine cells called acini, which secrete digestive enzymes

Question 15

What is an accessory pancreatic duct?

Answer 15

Most people have just one pancreatic duct.

However, some have an additional accessory pancreatic duct, called the Duct of Santorini

Question 16

The exocrine part of the pancreas is responsible for digestive function of the pancreas. How is this achieved? (2)

Answer 16

Secretion of bicarbonate by duct cells

Secretion of digestive enzymes by acinar cells

Question 17

What do Zymogens within the pancreas prevent?

Answer 17

autodigestion of the pancreas

Question 18

Where are enterokinase enzymes located?

Answer 18

bound to brush border of duodenal enterocytes

Question 19

Function of trypsin

Answer 19

breaks down proteins - aids digestion

converts all other zymogens to active forms

Question 20

Name some pancreatic enzymes (6)

Answer 20

Proteases

Nucleases

Elastases

Phospholipases

Lipases

α-Amylase

Question 21

Function of proteases

Answer 21

cleave peptide bonds

Question 22

alpha amylase function

Answer 22

starch to maltose + glucose

Question 23

Bicarbonate secretion from the pancreas is stimulated by what

Answer 23

secretin

Question 24

What is Zymogen secretion stimulated by?

Answer 24

CCK

Question 25

What is CCK released in response to?

Answer 25

Fat/amino acids in duodenum