lecture 21 - the stomach & pancreas

Question 1

How does the esophagus pass through the diaphragm and into the stomach?

Answer 1

Via the oesophageal hiatus

Question 2

What feature of the oesophagus prevents reflux from the stomach?

Answer 2

The lower oesophageal sphincter (LES)

Question 3

How does a bolus of food move through the oesophagus into the stomach?

Answer 3

Via peristalsis - a motility pattern - down the muscular oesophagus

Question 4

What are the 4 main parts of the stomach?

Answer 4

Cardia, fundus, body, pylorus

Question 5

What is the entry point of the stomach?

Answer 5

The cardia

Question 6

What is the top of the stomach?

Answer 6

The fundus

Question 7

What is the largest part of the stomach, making up the mid section?

Answer 7

The body

Question 8

What is the bottom/exit part of the stomach?

Answer 8

The pylorus

Question 9

what is the function of the pyloric antrum?

Answer 9

Connects the pylorus to the body of the stomach

Question 10

What is the top of the small intestine where the contents of the stomach passes into?

Answer 10

The duodenum

Question 11

What are the 2 omenta of the stomach?

Answer 11

Less and Greater omentum

Question 12

What does the lesser omentum of the stomach connect?

Answer 12

Stomach to liver

Question 13

What does the greater omentum of the stomach connect?

Answer 13

stomach to transverse colon

Question 14

What are the 2 curvatures of the stomach called?

Answer 14

The greater and lesser curvature

Question 15

How is the muscularis of the stomach adapted?

Answer 15

Modified for motility to promote mechanical digestion. Therefore, it has 3 layers rather than the usual 2

Question 16

What are the 3 layers of the muscularis in the stomach?

Answer 16

oblique (inner), circular (middle), longitudinal (outer)

Question 17

What part of the stomach has the thickest muscle?

Answer 17

The distal/bottom part to help move food through the stomach

Question 18

What is the name for the temporary folds on the internal surface of the stomach?

Answer 18

Rugae

Question 19

What is the function of the rugae of the stomach?

Answer 19

Temporary folds that allow for the expansion of the stomach for storage

Question 20

What is the structrue of a single stomach rugae?

Answer 20

Folded core of submucosa with overlying mucosa

Question 21

What do the gastric glands of the stomach secrete for digestion?

Answer 21

Acid & enzymes

Question 22

What do the gastric glands of the stomach secrete for protection?

Answer 22

Mucous

Question 23

What do the gastric glands of the stomach secrete for regulation?

Answer 23

hormones

Question 24

What are the 4 types of cells that make up gastric glands/pits?

Answer 24

Mucous epithelial cells (gastric pit) parietal cells, G cells, chief cells (gastric gland)

Question 25

What is a gastric pit?

Answer 25

A duct that lies at the surface above gastric glands and secretes mucous via mucous epithelial cells

Question 26

What are the 3 cell types of gastric glands?

Answer 26

parietal cells, G cells, chief cells

Question 27

What do parietal cells secrete?

Answer 27

Acid & intrinsic factor

Question 28

What do G cells secrete?

Answer 28

hormones (gastrin)

Question 29

What do chief cells secrete?

Answer 29

Enzymes, such as pepsinogen

Question 30

What is pepsinogen?

Answer 30

Active precursor of pepsin, secreted by chief cells within gastric glands

Question 31

How do parietal cells produce acid?

Answer 31

They pump protons (H+) against their concentration gradient out of the cell, using energy

Question 32

What are the features of parietal cells that reflect their function?

Answer 32

Abundant mitochondria to power ion pumping, and large surface area. Central nucleus as no granules taking up space at the apical aspect

Question 33

What are the features of chief cells that reflect their function?

Answer 33

Abundant rough ER for protein/enzyme processing, apical zymogen granules containing enzymes. Nucleus pushed to base of cell by full apical aspect

Question 34

What are the 2 mechanisms of stomach regulation?

Answer 34

Endocrine and neural control

Question 35

How does the stomach use the endocrine system for regulation of function?

Answer 35

Endocrine cells in the mucosa secrete the hormones gastrin and ghrelin into the bloodstream

Question 36

What are the 2 key hormones for endocrine regulation of the stomach?

Answer 36

Gastrin and ghrelin

Question 37

Where are the endocrine cells of the stomach found?

Answer 37

In the mucosa

Question 38

How does the stomach use the neural system for regulation of function?

Answer 38

The enteric nervous system (ENS) provides primary control and local reflexes, and this modulated by long neural reflexes from the CNS

Question 39

What is chyme?

Answer 39

Partially digested material, including acidic gastric acid and enzymes, that moves from the stomach into the duodenum

Question 40

What physically controls the release of chyme into the small intestine (duodenum)?

Answer 40

The pyloric sphincter (PS)

Question 41

What do the glands of the duodenum secrete?

Answer 41

Mucous, to protect the epithelium from the acidity of the chyme coming from the stomach

Question 42

Where do digestive enzymes and bicarbonate in the duodenum come from?

Answer 42

The pancreas

Question 43

What is the duodenal papilla?

Answer 43

The duct where fluid from the pancreatic and bile ducts pass into the lumen of the duodenum of the small intestine

Question 44

Where do the pancreatic and bile duct meet?

Answer 44

At the entrance of the hepato-pancreatic ampulla

Question 45

How is the release of substances from the duodenal papilla physically controlled?

Answer 45

By the hepatopancreatic sphincter

Question 46

What are the endocrine functions of the pancreas?

Answer 46

Secretion of glucagon and insulin to regulate blood glucose levels

Question 47

Where is insulin secreted?

Answer 47

Pancreatic islet beta cells

Question 48

What is the exocrine function of the pancreas?

Answer 48

Digestive function via secretion from glands. Acinar cells secrete digestive enzymes while duct cells secrete bicarbonate

Question 49

What is the function of pancreatic acinar cells?

Answer 49

Secrete enzymes for digestion.

Question 50

What is the structure of pancreatic acinar cells?

Answer 50

Have apical zymogen granules, basal nucleus, and abundant rough ER

Question 51

What cells of the pancreas secrete bicarbonate?

Answer 51

Pancreatic duct cells