Grand Tour of Alimentary Canal

Question 1

What are the 4 main functions of the digestive system?

Answer 1

Digestion
Secretion
Absorption
Motility

Question 2

What happens in the mouth at the start of the digestion process?

Answer 2

Food is broken down by chewing

Saliva is added as a lubricant

Question 3

What is the oesophagus?

Answer 3

Conduit between mouth and stomach

Question 4

What happens in the stomach?

Answer 4

Digestion of proteins
Food –> liquid form
Storage
Sterilisation

Question 5

What do enzymes from the pancreas digest?

Answer 5

Fats
Carbohydrates
Proteins

Question 6

What are found in the liver for digestion/absorption of fats in the small intestine?

Answer 6

Bile salts

Question 7

What does the gallbladder do?

Answer 7

Stores and concentrates bile

Question 8

What happens in the small intestine?

Answer 8

Final stages of chemical digestion and nutrient absorption

Question 9

What happens in the large intestine?

Answer 9

Water absorption
Bacterial fermentation
Formation of faeces

Question 10

What are the 4 distinctive layers of the alimentary canal?

Answer 10

Mucosa (epithelium, lamina propria, muscularis mucosae)
Submucosa
Muscularis externa
Serosa/adventitia

Question 11

What type of epithelium is found in the mouth, oesophagus and anal canal?

Answer 11

Stratified squamous

Question 12

What type of epithelium is found in the stomach, small/large intestine?

Answer 12

Simple columnar

Question 13

What is the function of epithelium in the mucosa?

Answer 13

Synthesis and secretion of digestive enzymes, hormones, mucus
Absorbs products of digestion
Barrier separating lumen of alimentary canal from body

Question 14

What is the lamina propria?

Answer 14

Loose connective tissue (glands, blood/lymph vessels)

Question 15

What is the muscularis mucosae?

Answer 15

Thin smooth muscle layer

Question 16

What is the submucosa?

Answer 16

Thick, irregular connectie tissue that supports the mucosa

Question 17

What does the submucosa contain?

Answer 17

Neurones, blood vessels, lymphatic vessels

Question 18

What do neurones form in the submucosa?

Answer 18

Submucosal (Meissner’s) plexus (parasympathetic)

Question 19

Where are the submucosal glands?

Answer 19

Oesophagus and duodenum

Question 20

What is the serosa/adventitia?

Answer 20

Connective tissue outer layer of alimentary canal

Question 21

What is the difference between serosa and adventitia layer?

Answer 21

Adventitia = outside peritoneal cavity, attaches oesophagus and rectum to surrounding structures
Serosa = inside peritoneal cavity, surrounds stomach, small intestine and large intestine

Question 22

What is the function of the inner layer of muscularis externa?

Answer 22

Circular muscle that constricts lumen

Question 23

What is the function of the outer layer of muscularis externa?

Answer 23

Longitudinal muscle that shortens tube

Question 24

What is the purpose of the 2 concentric layers of smooth muscle of the muscularis externa?

Answer 24

To produce motility for peristalsis and segmentation

Question 25

What is the name of the plexus between the circular and longitudinal muscle of the muscularis externa?

Answer 25

Myenteric (Auerbach's) plexus

Question 26

What does the combination of submucosal and myenteric plexuses form? + purpose

Answer 26

Enteric nervous system (ENS) which has independent control of gut function

Question 27

What supplies autonomic control on the alimentary system?

Answer 27

Long (parasympathetic) and short (ENS) reflexes

Question 28

What supplies parasympathetic control on the alimentary system? + effect

Answer 28

Vagus nerve Except salivation which is controlled by facial (VII) and glossopharyngeal nerves (IX) Stimulatory (increase in secretion and motility)

Question 29

What supplies sympathetic control on the alimentary system? + effect

Answer 29

Splanchnic nerve | Inhibitory (except salivation) = causes decrease in secretion and motility

Question 30

What organs does the celiac trunk supply?

Answer 30

Stomach Small intestine Pancreas Liver

Question 31

What organs does the superior mesenteric artery supply?

Answer 31

Small intestine Caecum Ascending colon Transverse colon

Question 32

What organs does the inferior mesenteric artery?

Answer 32

Descending colon Sigmoid colon Rectum

Question 33

Where does venous drainage from the stomach go to?

Answer 33

Gastric veins

Question 34

Where does venous drainage from the pancreas go to?

Answer 34

Splenic vein

Question 35

What structures drain into the superior mesenteric vein?

Answer 35

Small intestine Caecum Ascending colon Descending colon

Question 36

What structures drain into the inferior mesenteric vein?

Answer 36

Descending colon Sigmoid colon Rectum

Question 37

What veins drain into the hepatic portal vein?

Answer 37

Gastric veins Splenic vein Superior mesenteric vein Inferior mesenteric vein

Question 38

Where does the hepatic portal vein drain into?

Answer 38

Hepatic vein

Question 39

Where does the hepatic vein drain into?

Answer 39

Inferior vena cava