Session 9: Digestive system

Question 1

What are the four layers of the gut wall?

Answer 1

1. Mucosa (innermost)
2. Submucosa
3. Muscularis Externae
4. Serosa

Question 2

How many layers does the inner most layer of the gut, the mucosa, split into?

Answer 2

3

Question 3

What are the 3 layers of the mucosa layer of the gut?

Answer 3

1. Epithelium
2. Lamina proper
3. Mucularis mucosae

Question 4

What is the submucosa of the gut wall?

Answer 4

A layer of CT which contains glands, nerves and vessels.

Question 5

What is the function of the muscularis externae?

Answer 5

Peristaltic waves move luminal contents along the gut

Question 6

Which layer is closest to the lumen within the muscularis externae layer of the gut?

Answer 6

Circular muscle

Longitudinal muscle is closest to the exterior

Question 7

Describe the role of saliva.

Answer 7

• produces amylase to break down polysaccharides into monosaccharides
• bateristastatic properties
• assists swallowing

Question 8

TRUE OR FALSE: the upper 1/3 of the oesophagus is under voluntarily skeletal muscle control.

Answer 8

TRUE

Question 9

Does the oesophagus have the outermost serosa layer?

Answer 9

No as it is not in the abdomen.

Question 10

What are the 3 roles of the stomach?

Answer 10

1. Storage (we eat faster than we digest)
2. Initial destruction (via proteolytic enzymes and rhythmic contraction)
3. Disinfection (chyme and mucus secretion)

Question 11

What are rugae?

Answer 11

Infoldings of the stomach

Question 12

TRUE OR FALSE: the stomach has an additional ‘oblique’ layer of muscle in its muscularis externae layer.

Answer 12

TRUE- it is the innermost layer

Question 13

What is the role of the duodenum?

Answer 13

To release bicarbonate ions to neutralise acidic chyme.

Question 14

TRUE OR FALSE: adsorption of nutrients by the gut is a passive process

Answer 14

FALSE- it requires shit tons of energy

Question 15

What is the role of the jejunum?

Answer 15

Adsorb aa, fatty acids and sugars.

Question 16

What is the role of the ilium?

Answer 16

Absorb Vit B12 and bile acids to be recycled.

Question 17

What are intestinal glands also called?

Answer 17

crypts of Lieburkuhn

Question 18

TRUE OR FALSE: the small intestine contains most of the GI tracts bacteria

Answer 18

False: Only gut flora in small concentrations is found in the small intestine. Most of the GI tracts bacteria is found in the colon.

Question 19

Under what nervous system is the majority of the digestive system controlled?

Answer 19

Autonomic (only the top 1/3 of the oesophagus and last sphincter of the anus is voluntary)

Question 20

TRUE OR FALSE: The gut is controlled by hormones it makes its self rather than hormones synthesised elsewhere.

Answer 20

True

Question 21

Name three hormones associated with the digestive system.

Answer 21

1. Secretin
2. CCK
3. Gastrin

Question 22

What is the role of secretin?

Answer 22

• promotes bicarbonate ion secretion from the pancreas
• promotes bile production from the liver
• inhibits acid secretion from stomach

Question 23

What is the role of gastrin?

Answer 23

Promotes production of HCL by parietal cells of stomach.

Question 24

What is the role of CCK?

Answer 24

• promotes release of digestive enzyme from the pancreas
• promotes release of bile from the gall bladder
• suppresses hunger