Grand Tour of the Alimentary Canal

Question 1

What are the functions of the digestive system

Answer 1

Digestion, secretion, absorption, motility

Question 2

Function of mouth

Answer 2

Foodstuffs broken down by chewing; saliva added as lubricant

Question 3

Function of oesophagus

Answer 3

Conduit between mouth and stomach

Question 4

Function of stomach

Answer 4

Digestion of proteins; foodstuffs reduced to liquid form; storage; sterilisation

Question 5

Function of pancreas

Answer 5

Digestive enzymes for digestion of fats, carbohydrates and proteins

Question 6

Function of liver

Answer 6

Bile salts for digestion/absorption of fats in small intestine

Question 7

Function of gallbladder

Answer 7

Stores and concentrates bile

Question 8

Function of small intestine

Answer 8

Final stages of chemical digestion and nutrient absorption

Question 9

Function of the large intestine

Answer 9

Water absorption, bacterial fermentation and formation of faeces

Question 10

What are the 4 distinctive layers

Answer 10

Mucosa (epithelium, lamina propria, muscularis mucosa)

submucosa, muscularis externa, serosa/ adventitia

Question 11

Where is serosa found?

Answer 11

Found in organs inside the peritoneal cavity. Serosa surrounds stomach, small intestine and large intestine.

Question 12

Where is the adventitia found?

Answer 12

Found in organs outside the peritoneal cavity. Adventitia attaches oesophagus and rectum to surrounding structures.

Question 13

Where is stratified squamous epithelium found in the GI tract?

Answer 13

mouth, oesophagus, anal canal

Question 14

Where is simple columnar epithelium found?

Answer 14

stomach, small intestine, large intestine

Question 15

What is the function of epithelium?

Answer 15

barrier separating the lumen fo the alimentary canal from the body . synthesis and secretion of digestive enzymes, hormones and mucus. absorbs products of digestion

Question 16

Define lamina propria

Answer 16

Loose connective tissue (glands, blood/ lymph vessels)

Question 17

What is muscualris mucosae

Answer 17

thin smooth muscle layer

Question 18

What is the submucosa?

Answer 18

thick, irregular connective tissue.

Question 19

What does the submucosa contain?

Answer 19

Contains neurones, blood vessels, lymphatic vessels. neurons form extensive network Meissener’s plexus. submucosal glands in oesophagus and duodenum

Question 20

What is serosa/ adventitia?

Answer 20

connective tissue outer layer of the alimentary canal

Question 21

What is the muscularis externa?

Answer 21

Two concentric thick layers of smooth muscle.
Inner layer = circular muscle to constrict lumen
Outer layer = longitudinal muscle to shorten tube.

Question 22

Function of the muscularis externa?

Answer 22

produce motility (peristalsis and segmentation)
Myenteric (Auerbac's) plexus between circular and longitudinal muscle.

Question 23

What is the enteric nervous system

Answer 23

Submucosal and myenteric plexus = enteric nervous system. allows independent control of gut function.

Question 24

Autonomic control of the gut

Answer 24

Long (parasympathetic) and short (ENS) reflexes

Question 25

Parasympathetic nervous control of the gut?

Answer 25

Vagus nerve. except salivation (facial and glossopharyngeal) | stimulates increased secretion and motility

Question 26

Sympathetic nervous control of the gut

Answer 26

Splanchnic nerve. inhibitory (except salivation) decrease secretion and motility

Question 27

What are the organs supplied by the celiac trunk?

Answer 27

stomach, 2nd part of the duodenum pancreas and liver

Question 28

What organs are supplied by the superior mesenteric artery?

Answer 28

small intestine, caecum, ascending colon, transverse colon

Question 29

What organs are supplied by the inferior mesenteric artery?

Answer 29

descending colon, sigmoid colon, rectum

Question 30

What is the general venous drainage of the GI tract?

Answer 30

hepatic portal vein -> hepatic vein -> inferior vena cava

Question 31

What is the venous drainage of the stomach

Answer 31

Gastric veins

Question 32

What is the venous drainage of the pancreas?

Answer 32

splenic vein

Question 33

Which organs are drained by the superior mesenteric vein?

Answer 33

small intestine, caecum, ascending colon, transverse colon

Question 34

Which organs are drained by the inferior mesenteric vein?

Answer 34

descending colon, sigmoid colon, rectum

Question 35

Difference between hepatic artery, hepatic portal vein, hepatic vein

Answer 35

Hepatic artery = carries oxygenated blood from the heart to liver Hepatic portal vein = carries deoxygenated blood from the GI tract to the liver Hepatic vein = carries deoxygenated blood from the liver to the heart.