Gastric Motility and Pancreatic Function

Question 1

How does chyme mix in the antrum

Answer 1

Poweful contraction of antrum along with contraction of pyloric sphincter to ensure thorough mixing

Question 2

What produces gastric peristaltic waves

Answer 2

peristaltic rhythm produced by pacemake cells (longitudinal muscle) and slow waves that spontaneously polarise/Depolarise

Question 3

What controls slow wave rhythm

Answer 3

Basic electrical rhythm (BER)

Question 4

Where are slow waves conducted through

Answer 4

Gap junctions along longitudinal muscle layer

Question 5

What determines the strength of contraction?

Answer 5

Number of APs/Waves

Question 6

What does gastrin do?

Answer 6

Increases contraction

Question 7

What does distention of stomach wall do?

Answer 7

Activates long/short reflexes to decrease contraction

Question 8

What does fat/amino acid/hypertonicity do in duodenum?

Answer 8

Inhibits motility

Question 9

Where is bicarbonate secreted from?

Answer 9

Submucosal glands

Question 10

What does acid in duodenum trigger?

Answer 10

1. Long (vagal) and short (ENS) reflexes to release HCO3

2. Release of secretin from S cells that triggers HCO3 secretion from pancreas and liver

Question 11

What is the endocrine portion of spleen

Answer 11

islets of langerhans that produce insulin and glucagon and somatostatin that controls secretion of those two

Question 12

What is the exocrine portion of the pancreas

Answer 12

acinar cells that divide into lobules

Question 13

What two ducts lead to duodenum from pancreas

Answer 13

accessory pancreatic duct and main pancreatic duct => common bile duct

Question 14

What’s the order of structures from lobules to duodenum

Answer 14

Lobules connected by intercalated ducts  intralobular ducts  interlobular ducts  main pancreatic duct  common bile duct  hepatopancreatic ampulla (Sphincter of Oddi)  duodenum

Question 15

What secretes bicarbonate

Answer 15

Duct cells

Question 16

What secretes digestive enzymes

Answer 16

Acinar cells

Question 17

What converts trypsinogen to trypsin

Answer 17

Enterokinase

Question 18

Where is enterokinase found

Answer 18

On the brush border of duodenal enterocytes

Question 19

What does trypsin do

Answer 19

converts all other zymogens to active form

Question 20

What do 
-Elastases 
-Phospholipases
- Lipases 
-alpha-amylases 
do?

Answer 20

• Collagen digestion
• Phospholipids to fatty acids
• Triglycerides to glycerol and fatty acids
• Starch to maltose + GLUCOSE

Question 21

What stimulates bicarbonate secretion

Answer 21

Secretin in response to acid duodenum

Question 22

What is zymogen secretion stimulated by

Answer 22

cholycystokinin (CCK)

Question 23

Why is CCK released

Answer 23

In response to fat/amino acids in duodenum Under neural control