HUBS192 Lecture 21 - The Stomach and Pancreas

Question 1

what is the shape of the stomach?

Answer 1

J-shaped organ

Question 2

what is the oesophageal hiatus?

Answer 2

break or hole (junction) in the oesophagus to allow the oesophagus to pass through the stomach

Question 3

where is the stomach located?

Answer 3

located at the base of the oesophagus

Question 4

what is the function of the lower oesophageal sphincter (LES)?

Answer 4

prevents reflux of food material back up into the oesophagus

Question 5

how does the lower oesophageal sphincter allow the food bolus into the stomach?

Answer 5

relaxes to allow the food bolus to travel into the stomach and then contracts to prevent reflux

Question 6

what are the 4 main parts/regions of the stomach?

Answer 6

1) cardia
2) fundus
3) body
4) pylorus (pyloric antrum)

Question 7

what is cardia region of the stomach?

Answer 7

small region where the oesophagus opens up into the stomach

Question 8

what is the fundus region of the stomach?

Answer 8

proximal region where the gastric glands are located and gases produced as a byproduct of digestion collect

Question 9

what is the largest region of the stomach?

Answer 9

the body

Question 10

what is the pylorus (pyloric antrum) region of the stomach?

Answer 10

antrum= cave like
pylorus = gate keeper
where the pyloric sphincters acts as a gate keeper by regulating the passage of luminal content from the stomach into the first part of the small intestine

Question 11

what is the function of the pyloric sphincter?

Answer 11

regulates the process of gastric emptying

Question 12

what does the lesser omentum attach to?

Answer 12

attaches the lesser curvature of the stomach to the liver

Question 13

what does the greater omentum attach to?

Answer 13

attach to the greater curvature of the stomach and then folds back up to attach to the transverse colon

Question 14

what does the greater omentum contain?

Answer 14

a significant number of clusters of immune cells

• important for isolating infections
• first line of bacterial infection of the peritoneal cavity

Question 15

what are the modifications of the gut tube layers of the muscularis?

Answer 15

muscularis is modified for motility

Question 16

what are the 3 layers of the stomach?

Answer 16

1) oblique (inner)
2) circular (middle)
3) longitudinal (outer)

Question 17

where is the muscualris layer of the stomach thickest?

Answer 17

thickest in the distal region of the stomach (the pylorus) rather than the proximal region of the stomach (fundus)

Question 18

why is the muscularis thickest in the distal region of the stomach (pylorus) than the proximal region of the stomach (fundus)?

Answer 18

because there needs to be more contractility in the distal region of the stomach to aid in the mechanical and chemical digestion

Question 19

what are rugae?

Answer 19

temporary folds that allow for the expansion of the stomach (increase up to approx 1.5L)
-by flattening out

Question 20

what are rugae important for?

Answer 20

important for storage function

- and the sphcinters

Question 21

what are the components that make up the rugae?

Answer 21

folded core of submucosa with overlying mucosa
-this allows the flattening of the stomach
glands are permanent and only located in the mucosa

Question 22

what are the 3 things the stomach requires to perform its functions?

Answer 22

1) acid and enzymes for digestion
2) mucous for protection
3) hormones for regulation (motility and secretion)

Question 23

what are the 3 cells of gastric glands?

Answer 23

1) parietal cells
2) G cells
3) chief cells

Question 24

what do parietal cells secrete?

Answer 24

secrete acid and intrinsic factor

Question 25

what do G cells secrete?

Answer 25

secrete hormones into the blood (gastrin)

Question 26

what do chief cells secrete?

Answer 26

secrete pepsinogen (an inactive precursor of pepsin) aka enzymes

Question 27

what is abundant in chief cells?

Answer 27

• abundant in the rough endoplasmic reticulum
• significant amount of apical zymogen (enzyme) granules
• nucleus is in the basal layer

Question 28

what is abundant in parietal cells?

Answer 28

• secrete HCI by pumping ions (H+)
• abundant in mitochondria
• central nucleus
• folded structure to increase surface area

Question 29

what are the 2 ways to regulate stomach function?

Answer 29

1) endocrine control

2) neural control

Question 30

what are the 2 ways that endocrine control regulates stomach function?

Answer 30

1) endocrine cells in the mucosa

2) gastrin and gherlin secreted into the bloodstream

Question 31

what are the 2 ways that neural control regulates stomach function?

Answer 31

1) enteric nervous system (ENS) controls through local reflexes (primary control)
2) CNS modulates enteric nervous system (ENS) function through long neural reflexes

Question 32

what is the relationship of the diameter between the stomach and the first region of the small intestine?

Answer 32

large difference in diameter between the stomach and the first region of the small in intestine

Question 33

what is chyme?

Answer 33

the controlled release of digested material into the small intestine

Question 34

what does acidic chyme require as it enters the small intestine?

Answer 34

1) further digestion (enzymes and bicarbonate)
- provided by the pancreas
2) protection from acidic chyme
- mucous: provided by glands in the submucosa of the duodenum
- neutralise acid

Question 35

what is the shape of the pancreas in terms of its head and tail?

Answer 35

• head in C-shaped duodenum

- tail to spleen

Question 36

what is the duct where the pancreas delivers secretions?

Answer 36

delivers from the duct to the lumen of the duodenum

Question 37

what is the location of the pancreas?

Answer 37

posterior to the stomach (retroperitoneal)

Question 38

what does the liver produce and where does it store this?

Answer 38

liver produces and stores and concentrates this in the gale bladder

Question 39

where is the bile duct located?

Answer 39

bile duct meets pancreatic duct at the entrance to the hepatopancreatic ampulla

Question 40

what controls the release of bile?

Answer 40

release controlled by hepatopancreatic sphincter

Question 41

what projects into the duodenal lumen?

Answer 41

duodenal papilla projects into the duodenal lumen

Question 42

what are the endocrine functions of the pancreas?

Answer 42

1) pancreatic islet alpha cells secrete glucagon

2) pancreatic islet beta cells secrete insulin

Question 43

what are exocrine glands?

Answer 43

glands that secrete into the lumen of an organ

Question 44

what are the 2 functions of the pancreas?

Answer 44

1) acinar cells secrete digestive enzymes

2) duct cells secrete bicarbonate

Question 45

what is the structure of the pancreatic acinar cells?

Answer 45

-apical zymogen granules (transports enzymes towards the apical membrane to be exocytosed into the lumen)

Question 46

what is the function of apical zymogen granules?

Answer 46

transports enzymes towards the apical membrane to be exocytosed into the lumen

Question 47

what is the function of an pancreatic acinar cell?

Answer 47

to secrete enzymes

Question 48

what structures allow storage in the stomach?

Answer 48

• sphincters

- rugae: distension (folded submucosa)

Question 49

what does the stomach need for mechanical digestion?

Answer 49

• smooth muscle, additional oblique layer in the stomach

- sphincters

Question 50

what does the stomach need for chemical digestion?

Answer 50

• secretion of strong chemicals (acids, enzymes)

- protective epithelium