Upper GI Tract Structure and Function Flashcards Preview

Alimentary System > Upper GI Tract Structure and Function > Flashcards

Flashcards in Upper GI Tract Structure and Function Deck (55):
1

What do the upper and lower oesophageal sphincters regulate?

Movement of material into and out of the oesophagus

2

What are the four layers of the oesophagus?

Mucosa
Submucosa
Muscularis Externa
Adventitia

3

What kind of epithelium lines the mucosa of the oesophagus?

Stratified squamous epithelium

4

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

Mucous glands which secrete mucus via ducts to provide lubrication

5

What are the main functions of the stomach?

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

6

What is the function of the fundus of the stomach?

Storage

7

What are the functions of the body of the stomach?

Storage
Production of mucous, HCl, pepsinogen and intrinsic factor

8

What are the functions of the antrum of the stomach?

Mixing/grinding of stomach contents
Production of gastrin

9

The oesophagus leads to what opening in the stomach?

Gastro-oesophageal/cardiac opening

10

The lower oesophageal sphincter leads into what region?

The cardiac region

11

What are the two curvatures of the stomach?

Lesser curvature
Greater curvature

12

The pyloric sphincter leads into the

duodenum

13

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

Mucosa
Submucosa
Muscularis externa

14

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

Whether the organ is intraperitoneal or retroperitoneal

15

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

serosa

16

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

adventitia

17

The enteric nervous system is under control by what systems?

Parasympathetic and sympathetic

18

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

Vagus nerve

19

What nerves control salivation?

7th facial and 9th glossopharyngeal nerves

20

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

Stimulatory - increases secretion and motility

21

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

Splanchnic nerve

22

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

Inhibitory

23

What is the mesentery?

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

24

What are the main arterial supplies of the gastrointestinal tract?

Coeliac trunk
Superior mesenteric artery
Inferior mesenteric artery

25

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

Circular folds
Villi
Microvilli

26

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

Microvilli - increase relative absorptive surface area by 600

27

The oesophagus acts as a conduit between what?

The pharynx and the stomach

28

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

Skeletal

29

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

Smooth

30

What is the relation of the oesophagus to the aorta?

Oesophagus lies anterior to the aorta

31

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

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

32

What are the three phases of swallowing?

Oral phase
Pharyngeal phase
Oesophageal phase

33

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

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

34

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

Th nasopharynx

35

As the bolus approaches the oesophagus, what sphincter relaxes?

The upper oesophageal sphincter

36

The epiglottis covers what?

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

37

The upper oesophageal sphincter contracts once

food has entered the oesophagus

38

What does the oesophageal phase involve?

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

39

As the bolus nears the stomach, what sphincter relaxes?

The lower oesophageal sphincter

40

The relaxation of the stomach is initiated following

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

41

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

Vagal

42

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

From 50ml to 1500ml

43

What are the main functions of the duodenum?

Gastric neutralisation
Digestion
Iron absorption

44

What is the function of gastric neutralisation?

Allows pancreatic enzymes to function and prevents acid damage to duodenum

45

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

Bicarbonate
Secreted from the duct cells in the submucosal glands

46

Bicarbonate combines with acid in the stomach to produce

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

47

What cells are contained in the endocrine pancreas?

Islets of Langerhans

48

What are the functions of the Islets of Lagerhans?

Produce insulin, glucagon and somatostatin

49

What does somatostatin control?

The secretion of insulin and glucagon

50

The exocrine pancreas is composed of what cells?

Acinar cells

51

What are the lobules of the exocrine pancreas connected by?

Intercalated ducts

52

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

Main pancreatic duct

53

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

hepatopancreatic ampulla

54

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

Alpha - glucagon
Beta - insulin

55

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

The digestive functions