Gastric Motility and Pancreatic Function

Question 1

Is the peristaltic contraction in the body of the stomach made by thin or thick muscle and what is the strength of it’s contraction?

Answer 1

Thin muscle - weak contraction

Question 2

Is the peristaltic contraction in the antrum of the stomach made by thin or thick muscle and what is the strength of it’s contraction?

Answer 2

Thick muscle - powerful contraction

Question 3

What part of the stomach does mixing occur in?

Answer 3

Antrum

Question 4

What is chyme?

Answer 4

Gastric content

Question 5

What is the peristaltic rhythm (No/min)

Answer 5

3/min

Question 6

What generates the peristaltic rhythm?

Answer 6

Pacemaker cells from the longitudinal muscle layer

Question 7

How do peristaltic slow waves occur?

Answer 7

Spontaneous depolarisation/repolarisation

Question 8

What is the slow wave rhythm known as?

Answer 8

The basic electrical rhythm (BER)

Question 9

Where are slow waves conducted through?

Answer 9

Gap junctions along the longitudinal muscle layer

Question 10

What determines the strength of contraction for the slow waves?

Answer 10

The number of action potentials per wave

Question 11

What are 2 examples of neural/hormonal control that increase the contraction of slow waves?

Answer 11

Gastrin

Distension of stomach wall (activates long/short reflexes)

Question 12

Where is bicarbonate (HCO3) secreted from in the duodenum?

Answer 12

Brunner’s gland duct cells (found in the submucosa)

Question 13

What is the function of HCO3 in the duodenum?

Answer 13

To neutralise acid

Question 14

What are the 2 mechanisms of HCO3 secretion that acid in the duodenum triggers?

Answer 14

Long (vagal) and short (ENS) reflexes

Release of secretin from S cells

Question 15

What are the 3 parts of the pancreas?

Answer 15

Head
Body
Tail

Question 16

Where is the head of the pancreas located within?

Answer 16

The curvature of the duodenum

Question 17

Where does the tail of the pancreas extend towards?

Answer 17

The spleen

Question 18

What is the endocrine portion of the pancreas?

Answer 18

The pancreatic islets (islets of Langerhans)

Question 19

What 3 substances are produced by the islets of Langerhans in the pancreas?

Answer 19

Insulin
Glucagon
Somatostatin

Question 20

What is the exocrine portion of the pancreas?

Answer 20

Aciner cells (which form the lobules)

Question 21

What do aciner cells produce?

Answer 21

Pancreatic enzymes

Question 22

What allows the pancreatic enzymes to move out from the lobules?

Answer 22

Intercalated ducts

Question 23

Describe the route from the intercalated ducts to the main pancreatic duct?

Answer 23

intercalated duct - intralobular duct - interlobular duct - main pancreatic duct

Question 24

Which cells in the pancreatic islets secrete glucagon?

Answer 24

Alpha cells

Question 25

Which cells in the pancreatic islets secrete insulin?

Answer 25

Beta cells

Question 26

Where are the products of the pancreatic islets transported to?

Answer 26

The bloodstream

Question 27

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

Answer 27

Inactive zymogen granules

Question 28

Why is it important that the enzymes are stored as inactive zymogen granules?

Answer 28

Prevents autodigestion of the pancreas

Question 29

What does enterokinase (pancreatic digestive enzyme) convert?

Answer 29

Trypsinogen to Trypsin

Question 30

What is the role of trypsin?

Answer 30

Converts zymogens to their active forms