Grand Tour of Alimentary Canal

Question 1

What are the 4 functions of the digestive system?

Answer 1

• Digestion
• Secretion
• Absorption
• Motility

Question 2

What happens in the mouth?

Answer 2

Foodstuffs broken down by chewing. Saliva added as lubricant

Question 3

What happens in the oesophagus?

Answer 3

Acts as a conduit between the mouth and the stomach

Question 4

What happens in the stomach?

Answer 4

• Digestion of proteins
• Foodstuffs reduced to liquid form
• Storage
• Sterilisation

Question 5

What happens in the pancreas?

Answer 5

Digestive enzymes for digestion of fats, carbohydrates and proteins

Question 6

What happens in the liver?

Answer 6

Bile salts for digestion/absorption of fats in small intestine

Question 7

What happens in the gallbladder?

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 and formation of faeces

Question 10

What is the general structure of the alimentary canal?

Answer 10

• Continuous hollow tube of varying diameter
• Spans from oesophagus to the rectum
• 8m long
• Tube wall has same structural organisation throughout length

Question 11

What are the 4 distinctive layers of the alimentary canal?

Answer 11

• Mucosa
• Submucosa
• Muscularis extena
• Serosa/adventitia

Question 12

What are the 3 components of the mucosa?

Answer 12

• Epithelium
• Lamina propria
• Muscularis mucosae

Question 13

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

Answer 13

Stratified squamous

Question 14

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

Answer 14

Simple columnar

Question 15

Why does the epithelium differ along the length of the gut tube?

Answer 15

Adaption for function

Question 16

What is the function of the epithelium?

Answer 16

• Acts as a barrier separating lumen of the alimentary canal from the body
• Synthesis and secretion of digestive enzymes, hormones and mucus
• Absorbs products of digestion

Question 17

What is the lamina propria?

Answer 17

Loose connect tissue

Question 18

What is the muscularis mucosae?

Answer 18

Thin smooth muscle layer

Question 19

What is the submucosa?

Answer 19

Thick, irregular connective tissue that supports mucosa

Question 20

What does the submucosa contain?

Answer 20

Neurones, blood vessels and lymphatic

Question 21

What do the blood vessels contained within the submucosa supply?

Answer 21

• Mucosa
• Muscularis externa
• Serosa

Question 22

What do the neurones contained within the submucosa form?

Answer 22

An extensive network known as the submucosal plexus

Question 23

Where can submucosal glands be found?

Answer 23

• Oesophagus

- Duodenum

Question 24

What is the serosa/adventitia?

Answer 24

Connective tissue outer layer of the alimentary canal

Question 25

What is the outer layer of the alimentary canal outside of the peritoneal cavity?

Answer 25

Adventitia that attaches the oesophagus and rectum to surrounding structures

Question 26

What is the outer layer of the alimentary canal inside the peritoneal cavity?

Answer 26

Serosa surrounds the stomach, small intestine and large intestine

Question 27

What is the muscularis externa composed of?

Answer 27

-Two concentric thick layers of smooth muscle

Question 28

What are the 2 layers of the muscularis externa?

Answer 28

- Inner layer= circular muscle which constricts the lumen | - Outer layer= longitudinal muscle which shortens the tube

Question 29

What is the function of the muscularis externa?

Answer 29

-Produce motility through peristalsis and segmentation

Question 30

What neural plexus is located between the circular and longitudinal muscle?

Answer 30

Myenteric (Auerbach's) plexus

Question 31

What is the enter nervous system composed of?

Answer 31

- Submucosal plexus | - Myenteric plexus

Question 32

What does the enteric nervous system allow?

Answer 32

Independent control of gut function

Question 33

What is the autonomic control of the alimentary system?

Answer 33

- Long (parasympathetic) | - Short (ENS)

Question 34

What nerve is responsible for parasympathetic control of the alimentary system?

Answer 34

Vagus nerve

Question 35

How does the parasympathetic system act on the alimentary system?

Answer 35

Stimulatory - Increase secretion - Increases motility

Question 36

How does the sympathetic system act on the alimentary system?

Answer 36

Inhibitory - Decreases secretion - Decreases motility

Question 37

What nerve is responsible for sympathetic control of the alimentary system?

Answer 37

Splanchnic nerve

Question 38

What nerves are responsible for salivation?

Answer 38

Facial and glossopharyngeal

Question 39

What does the celiac trunk supply?

Answer 39

- Stomach - Small intestine - Pancreas - Liver

Question 40

What does the superior mesenteric artery supply?

Answer 40

- Small intestine - Caecum - Ascending colon - Transverse colon

Question 41

What does the inferior mesenteric artery supply?

Answer 41

- Descending colon - Sigmoid colon - Rectum

Question 42

What drains the stomach?

Answer 42

Gastric veins

Question 43

What drains the pancreas?

Answer 43

Splenic vein

Question 44

What does the superior mesenteric vein drain?

Answer 44

- Small intestine - Caecum - Ascending colon - Transverse colon

Question 45

What does the inferior mesenteric vein drain?

Answer 45

- Descending colon - Sigmoid colon - Rectum

Question 46

What drains into the hepatic portal vein?

Answer 46

- Gastric veins - Splenic vein - Superior mesenteric vein - Inferior mesenteric vein

Question 47

What does the hepatic portal vein drain into?

Answer 47

Hepatic vein

Question 48

What drains into the inferior vena cava?

Answer 48

Hepatic vein