Gastric Motility and Pancreatic Function

Question 1

Why does no mixing occur due to peristaltic waves in the body of the stomach

Answer 1

The presence of thin muscle, mean only a weak contraction occurs

Question 2

How does thorough mixing occur in the antrum of the stomach due to peristalic waves

Answer 2

Peristalic waves occur and cause the pyloric spinchter to contract

therefore encourages mixing of contents while only a small amount of chyme enter duodenum to then be forced back up by spinchter for further mixng

Question 3

What generates peristaltic waved

Answer 3

Pacemaker cells found in the longitudinal muscle layer

Question 4

How is there a basic electrical rhythm of peristaltic waves

Answer 4

Due to spontaneous depolarisation and re-polorisation conducted through the gap junctions in the longitudinal muscle
creating a constant slow wave

Question 5

How does a contraction occur above peristaltic waves basic electrical rhythm

Answer 5

Further depolarisation occurs above sub threshold inducing AP and causing a contraction

Question 6

What two things increase the level of contractions in the stomach

Answer 6

Gastrin

Distension of stomach wall -

Question 7

What inhibits contractions in peristaltic waves

Answer 7

Fat/acid/amino acid/hypertonicity in duodenum decreases gastrin production therefore decreases motility

Question 8

How does the distension of the stomach wall increase the level of contraction

Answer 8

Distension stimulates Long/short reflex via vagus nerve

releasing ACH to stimuli above sub threshold

Question 9

What is secreted from Brunners glands found in the submucosa of the duodenum

Answer 9

Bicarbonate

Question 10

What is the purpose of Bicarbonate secretion

Answer 10

To neutralise the acid in the stomach

Question 11

What are the two ways bicaboante secretion is stimulates

Answer 11

When acid is present the duodenum
stimulates long/short ENS reflex which triggers the release of bicarbonate

and stimulates the release of secretin which triggers the release of bicarbonate

Question 12

How is there a negative feedback control in acid neutralisation

Answer 12

Once acid has been neutralised it feedback and inhibits secretin release

Question 13

What does the hormone secretin do

Answer 13

Decreases acid secretion

Increase Bicarbonate secretion

Decreases gastric emptying time

Question 14

Where is secretin secreted from

Answer 14

S cells

Question 15

What is present in the endocrine portion of the pancreas

Answer 15

Pancreatic inlets - Islets of langerhan

Question 16

What is Secreated by the islet of langerhan

Answer 16

Insulin (alpha)
Glucagon (beta)
Somatostatin

Question 17

What is the function of somatostatin

Answer 17

Controls the secretion of insulin and glucagon

Question 18

What cells are present in the exocrine portion of the pancrease

Answer 18

Accinar cells that come together to from lobules

Duct cells

Question 19

What do accinar cells come together to fuse and how are the connected

Answer 19

Lobules connected via intercalated ducts

Question 20

How does the lobules feed into the main pancreatic duct

Answer 20

Intercalated ducts feed into intralobular duct which then feeds into interlobular, which then feed into the main pancreatic duct

Question 21

What fuses with the main pancreatic duct before entering the duodenum

Answer 21

Bile duct

Question 22

How does the main pancreatic duct enters the duodenum

Answer 22

enters via the hepatopancreatic ampulla - spinchter of oddi

Question 23

If the pancreatic duct no longer works how does it feed into the duodenum

Answer 23

through the accessory pancreatic duct

Question 24

What kind of cells are the duct cells in the pancreas

Answer 24

cubodial

Question 25

What is the function of accinar cells

Answer 25

Secretes digestive enzyme

Question 26

What is the function of duct cells

Answer 26

secreate bicarbonate

Question 27

How does the digestive enzymes not autodiggest the pancreas

Answer 27

Are stored in inactive form called zymogen granules

Question 28

How are digestive enzymes converted to active form

Answer 28

Due to membrane bound enterokinase converting trypsinogen to trypsin and trypsin further converting inactive enzymes to active from

Question 29

Where is enterokinase found

Answer 29

On the membrane of the duodenum

Question 30

What hormone stimulates the release of inactive digestive enzymes (zymogen) from the pancreas

Answer 30

Cholecystokini

Question 31

When is cholecystokinin released

Answer 31

Released un the response of organic nutrients e.g. fat or amino acids in duodenum

Question 32

When is cholecystokini released under neural control

Answer 32

Due to parasympathetic innervation through the vagal nerve and local reflexes

Question 33

Name the 6 pancreatic enzymes

Answer 33

Proteases
Elastases
Nucleases

Phospholipases
α-Amylase
Lipases

PEN PAL

Question 34

What is the function of protease

Answer 34

Cleave peptide bonds

Question 35

What is the function of nuclease

Answer 35

Hydrolyse DNA / RNA

Question 36

What is the function of elastase

Answer 36

Collages digestion

Question 37

What is the function of Phospholipases

Answer 37

break down phospholipids to fatty acids

Question 38

What is the function of lipase

Answer 38

Break down of Triglycerides to fatty acids+ glycerol

Question 39

What is the function of α-Amylase

Answer 39

Breakdown of starch to maltose and glucose

Question 40

Where is all the places that secrete bicarbonate stimulated by secretin

Answer 40

Duodenal - brunners glands in submucosa
Pancreatic - duct cells
Bile duct