Gastric motility and pancreatic function

Question 1

Does mixing happen in the body or antrum of the stomach?

Answer 1

antrum

Question 2

Explain the differences in muscle and contractions in the body and antrum of the stomach

Answer 2

body - thin and weak

antrum - thick and strong

Question 3

What are 2 consequences of the pyloric sphincter contracting?

Answer 3

small amount of content enters the duodenum

contents not gone through are pushed back up and causes a further mixing of antral contents

Question 4

What is chime?

Answer 4

liquid slurry

Question 5

What is the peristaltic rhythm generated by and how many occur in a minute?

Answer 5

3

pacemaker cells

Question 6

Where are the pacemaker cells found in the stomach?

Answer 6

Longitudinal muscle layer and particularly in the top portion of the stomach

Question 7

What are slow waves?

Answer 7

random depolarisation and repolarisation which are driven by the pacemaker cells

Question 8

What is the basic electrical rhythm of the gut?

Answer 8

The slow wave rhythm

Question 9

How does the BER travel?

Answer 9

along the longitudinal muscle layer through gap junctions

Question 10

What determines the strength of contraction?

Answer 10

Frequency of action potentials

Question 11

What 2 things increase the force of contraction?

Answer 11

Gastrin and wall distension

Question 12

What 4 things inhibit motility?

Answer 12

acid, hypertonicity, fat, amino acid

anything signalling the stomach is emptying

Question 13

What cells secrete bicarbonate?

Answer 13

brunners glands - submucosal glands

Question 14

What 2 things promote bicarbonate secretion?

Answer 14

vagal + ENS reflex

secretin

Question 15

Where is secretin produced?

Answer 15

S cells in the duodenum

Question 16

Where is bicarbonate secreted from (organ)

Answer 16

pancreas and liver

Question 17

What mechanism is secretin production controlled by?

Answer 17

negative feedback

Question 18

Name the 3 parts of the pancreas

Answer 18

head, body and tail

Question 19

Give the relative anatomical positions of the head and tail of pancreas

Answer 19

head - in curve of duodenum

tail - to the spleen

Question 20

What makes up the exocrine part of the pancreas?

Answer 20

acinar cells and lobules

Question 21

What does the endocrine part of the pancreas secrete?

Answer 21

somatostatin to control the secretion of the other 2 compounds released - insulin and glucagon to control blood glucose

Question 22

Why is there an accessory pancreatic duct?

Answer 22

in case of blockage can still get the secretions into the duodenum

Question 23

Describe the make-up of the exocrine pancreas

Answer 23

acini cells make up individual lobules
Each lobule has an associated intercalated duct
Many intercalated ducts form an intralobular duct
Many intralobular ducts form the interlobular ducts which lead to the pancreatic duct

Question 24

How does the pancreatic duct enter the duodenum?

Answer 24

joins with the common bile duct to enter via the sphincter of Oddi

Question 25

What portion of the pancreas is digestion concerned with?

Answer 25

exocrine

Question 26

What do the duct cells secrete?

Answer 26

bicarbonate

Question 27

What do the acini cells secrete?

Answer 27

digestive enzymes

Question 28

How are the digestive enzymes stored in the acinar cells? Why?

Answer 28

As zymogens

to prevent autodigestion of the pancreas

Question 29

What enzyme controls the conversion of all other zymogens?

Answer 29

trypsin from trypsinogen

Question 30

How is trypsin formed?

Answer 30

from trypsinogen due to the enterokinase bound to the brush border of the duodenal enterocytes

Question 31

Give an example of some pancreatic enzymes and their roles

Answer 31

proteases- break down protein, nucleases-break down DNA, elastases-break down collagen, phospholipases-phospholipid–>FA, lipases-TAG–>FA and glycerol, alpha amylase - starch/glycogen–>maltose +glucose

Question 32

What stimulates secretin production and what does secretin do?

Answer 32

acid in duodenum

stimulates bicarbonate secretion from pancreas

Question 33

What stimulates CCK production and what does CCK do?

Answer 33

fat/amino acids in duodenum

zymogen release from acinar cells

Question 34

What stimulates neural control of pancreas?

Answer 34

organic nutrients in the duodenum