Lecture 8 Gastric Motility and Pancreatic Function

Question 1

What is the difference between the body of the stomach and antrum

Answer 1

Body has thin muscle as there is no mixing and weak contraction. The antrum has thick muscle for powerful contraction

Question 2

What produces gastric peristaltic waves

Answer 2

Generated by pacemaker cels in longitudinal muscle layer

Question 3

How are the slow waves in peristalsis conducted

Answer 3

Through gap junctions along longitudinal muscle layer

Question 4

Describe the depolarisation of slow waves during peristalsis

Answer 4

Slow wave depolarisation sub-threshold that requires further depolarisation to induce action potential

Question 5

What does the number of APs determine

Answer 5

Strength of contraction

Question 6

What is the effect of gastrin

Answer 6

Increases contraction

Question 7

What happens when there is • Fat/acid/amino acid/hypertonicity in duodenum

Answer 7

inhibition of motility- controls acid, osmolarity and nutrients leaving the stomach

Question 8

Where is Bicarbonate secreted from and what is its role

Answer 8

Brunner’s gland duct cells in the submucosa.
Enzymes from the pancreas do not operate at a low pH so neutralisation is required as well as the duodenum not being protected by a mucous secreting epithelium

Question 9

What does acid in the duodenum trigger

Answer 9

Long (vagal) & short (ENS) reflexes that cause bicarbonate secretion.
Release of secretin from S cells which act on Brunner’s gland to release bicarbonate

Question 10

Describe the negative feedback control in bicarbonate secretion

Answer 10

Acid neutralisation inhibits secretin release

Question 11

Name the 3 parts of the pancreas

Answer 11

Head, body and tail

Question 12

Where is the head of the pancreas located

Answer 12

Curvature of duodenum

Question 13

Where is the tail of the pancreas located

Answer 13

Extends to the spleen

Question 14

What is the role of the endocrine portion of the pancreas

Answer 14

Contain islets of Langerhans which produce insulin and glucagon

Question 15

What is the role of the exocrine portion

Answer 15

formed of acinar cells which become lobules connected by interacted ducts and follow through to the common bile duct and responsible for digestion

Question 16

Where does the common bile duct enter the duodenum from

Answer 16

hepatopancreatic ampulla (sphincter of Oddi)

Question 17

If the bile duct s blocked where can bile enter the duodenum from

Answer 17

Accessory pancreatic duct

Question 18

What is the function of the exocrine pancreas

Answer 18

• Secretion of bicarbonate by duct cells

* Secretion of digestive enzymes by acinar cells

Question 19

What is enterokinase

Answer 19

Bound to brush border of duodenal enterocytes and converts trypsinogen to trypsin

Question 20

What is the function of trypsin

Answer 20

Converts all zymogens to active forms in the duodenum

Question 21

Name the pancreatic enzymes

Answer 21

Proteases
Nucleases
Elastases
Phosphlipases
Lipases
Amylase

Question 22

Role of Proteases

Answer 22

Clean peptide bonds

Question 23

Role of Nucleases

Answer 23

Hydrolyse DNA/RNA

Question 24

Role of Elastase

Answer 24

Collagen digestion

Question 25

Role of Phospholipas

Answer 25

Phospholipids to fatty acids

Question 26

Role of lipases

Answer 26

Triglycerides to fatty acid and glycerol

Question 27

Role of amylase

Answer 27

Starch to maltose and glucose

Question 28

What stimulates the secretion of biarbonate

Answer 28

Secretin

Question 29

What stimulates the release of secretin

Answer 29

Acid in the duodenum

Question 30

What stimulates zymogen

Answer 30

CCK

Question 31

What is CCK released in response to

Answer 31

Fat/amino acids in duodenum