Upper GI Tract Structure and Function

Question 1

What do the upper and lower oesophageal sphincters regulate?

Answer 1

Movement of material into and out of the oesophagus

Question 2

What are the four layers of the oesophagus?

Answer 2

Mucosa
Submucosa
Muscularis Externa
Adventitia

Question 3

What kind of epithelium lines the mucosa of the oesophagus?

Answer 3

Stratified squamous epithelium

Question 4

The submucosa of the oesophagus contains what glands, and what is their function?

Answer 4

Mucous glands which secrete mucus via ducts to provide lubrication

Question 5

What are the main functions of the stomach?

Answer 5

Temporary storage of ingested material
Dissolve food particles and initiate digestion
Control delivery of contents to small intestine
Sterilise ingested material
Produce intrinsic factor

Question 6

What is the function of the fundus of the stomach?

Answer 6

Storage

Question 7

What are the functions of the body of the stomach?

Answer 7

Storage

Production of mucous, HCl, pepsinogen and intrinsic factor

Question 8

What are the functions of the antrum of the stomach?

Answer 8

Mixing/grinding of stomach contents

Production of gastrin

Question 9

The oesophagus leads to what opening in the stomach?

Answer 9

Gastro-oesophageal/cardiac opening

Question 10

The lower oesophageal sphincter leads into what region?

Answer 10

The cardiac region

Question 11

What are the two curvatures of the stomach?

Answer 11

Lesser curvature

Greater curvature

Question 12

The pyloric sphincter leads into the

Answer 12

duodenum

Question 13

What are the three common components of the alimentary canal wall?

Answer 13

Mucosa
Submucosa
Muscularis externa

Question 14

The fourth layer of the alimentary canal wall is dependent on what?

Answer 14

Whether the organ is intraperitoneal or retroperitoneal

Question 15

If an organ is intraperitoneal, the fourth layer of its wall is

Answer 15

serosa

Question 16

If an organ is retroperitoneal, the fourth layer of its wall is

Answer 16

adventitia

Question 17

The enteric nervous system is under control by what systems?

Answer 17

Parasympathetic and sympathetic

Question 18

What is the innervation of the enteric nervous system from the parasympathetic system?

Answer 18

Vagus nerve

Question 19

What nerves control salivation?

Answer 19

7th facial and 9th glossopharyngeal nerves

Question 20

What effect does the parasympathetic system have on the alimentary system?

Answer 20

Stimulatory - increases secretion and motility

Question 21

What is the innervation of the enteric nervous system from the sympathetic system?

Answer 21

Splanchnic nerve

Question 22

What effect does the sympathetic system have on the alimentary system?

Answer 22

Inhibitory

Question 23

What is the mesentery?

Answer 23

Fold of membranous tissue arising from the posterior wall of the peritoneal cavity which attaches organs to the posterior abdominal wall

Question 24

What are the main arterial supplies of the gastrointestinal tract?

Answer 24

Coeliac trunk
Superior mesenteric artery
Inferior mesenteric artery

Question 25

What three features of the small intestine act to increase the absorptive surface area along the alimentary canal?

Answer 25

Circular folds Villi Microvilli

Question 26

What feature of the small intestine causes the highest increase in the relative absorptive surface area of the alimentary canal?

Answer 26

Microvilli - increase relative absorptive surface area by 600

Question 27

The oesophagus acts as a conduit between what?

Answer 27

The pharynx and the stomach

Question 28

The muscularis externa of the superior oesophagus is composed of what kind of muscle?

Answer 28

Skeletal

Question 29

The muscularis external of the inferior oesophagus is composed of what kind of muscle?

Answer 29

Smooth

Question 30

What is the relation of the oesophagus to the aorta?

Answer 30

Oesophagus lies anterior to the aorta

Question 31

What phase of swallowing is voluntary and what happens in this phase?

Answer 31

Oral phase - bolus is pushed to the back of the mouth by the tongue

Question 32

What are the three phases of swallowing?

Answer 32

Oral phase Pharyngeal phase Oesophageal phase

Question 33

The presence of the bolus causes what in the pharyngeal muscles?

Answer 33

Sequence of reflex contractions, coordinated by the swallowing centre in the medulla

Question 34

What is closed off when the soft palate is reflected backwards and upwards?

Answer 34

Th nasopharynx

Question 35

As the bolus approaches the oesophagus, what sphincter relaxes?

Answer 35

The upper oesophageal sphincter

Question 36

The epiglottis covers what?

Answer 36

The opening to the larynx - preventing food from entering the trachea

Question 37

The upper oesophageal sphincter contracts once

Answer 37

food has entered the oesophagus

Question 38

What does the oesophageal phase involve?

Answer 38

The propulsion of the bolus to the stomach via a peristaltic wave which sweeps along the entire oesophagus

Question 39

As the bolus nears the stomach, what sphincter relaxes?

Answer 39

The lower oesophageal sphincter

Question 40

The relaxation of the stomach is initiated following

Answer 40

the relaxation of the lower oesophageal sphincter and entry of bolus into the stomach

Question 41

What reflexes cause the relaxation of the thin, elastic smooth muscle of the gastric fundus and body?

Answer 41

Vagal

Question 42

Relaxation of the smooth muscle of the gastric fundus and body increase stomach volume by how much?

Answer 42

From 50ml to 1500ml

Question 43

What are the main functions of the duodenum?

Answer 43

Gastric neutralisation Digestion Iron absorption

Question 44

What is the function of gastric neutralisation?

Answer 44

Allows pancreatic enzymes to function and prevents acid damage to duodenum

Question 45

Brunner's glands secrete what? What cells is this product secreted from?

Answer 45

Bicarbonate | Secreted from the duct cells in the submucosal glands

Question 46

Bicarbonate combines with acid in the stomach to produce

Answer 46

carbonic acid, which then breaks down to produce water and carbon dioxide

Question 47

What cells are contained in the endocrine pancreas?

Answer 47

Islets of Langerhans

Question 48

What are the functions of the Islets of Lagerhans?

Answer 48

Produce insulin, glucagon and somatostatin

Question 49

What does somatostatin control?

Answer 49

The secretion of insulin and glucagon

Question 50

The exocrine pancreas is composed of what cells?

Answer 50

Acinar cells

Question 51

What are the lobules of the exocrine pancreas connected by?

Answer 51

Intercalated ducts

Question 52

What duct is formed by the joining of the interlobular ducts?

Answer 52

Main pancreatic duct

Question 53

The main pancreatic duct joins the common bile duct, these both join the duodenum at the

Answer 53

hepatopancreatic ampulla

Question 54

What do the alpha and beta cells of the pancreas produce?

Answer 54

Alpha - glucagon | Beta - insulin

Question 55

What functions of the pancreas is the exocrine pancreas responsible for?

Answer 55

The digestive functions