Session 9: Digestive system Flashcards
What are the four layers of the gut wall?
- Mucosa (innermost)
- Submucosa
- Muscularis Externae
- Serosa
How many layers does the inner most layer of the gut, the mucosa, split into?
3
What are the 3 layers of the mucosa layer of the gut?
- Epithelium
- Lamina proper
- Mucularis mucosae
What is the submucosa of the gut wall?
A layer of CT which contains glands, nerves and vessels.
What is the function of the muscularis externae?
Peristaltic waves move luminal contents along the gut
Which layer is closest to the lumen within the muscularis externae layer of the gut?
Circular muscle
Longitudinal muscle is closest to the exterior
Describe the role of saliva.
- produces amylase to break down polysaccharides into monosaccharides
- bateristastatic properties
- assists swallowing
TRUE OR FALSE: the upper 1/3 of the oesophagus is under voluntarily skeletal muscle control.
TRUE
Does the oesophagus have the outermost serosa layer?
No as it is not in the abdomen.
What are the 3 roles of the stomach?
- Storage (we eat faster than we digest)
- Initial destruction (via proteolytic enzymes and rhythmic contraction)
- Disinfection (chyme and mucus secretion)
What are rugae?
Infoldings of the stomach
TRUE OR FALSE: the stomach has an additional ‘oblique’ layer of muscle in its muscularis externae layer.
TRUE- it is the innermost layer
What is the role of the duodenum?
To release bicarbonate ions to neutralise acidic chyme.
TRUE OR FALSE: adsorption of nutrients by the gut is a passive process
FALSE- it requires shit tons of energy
What is the role of the jejunum?
Adsorb aa, fatty acids and sugars.
What is the role of the ilium?
Absorb Vit B12 and bile acids to be recycled.
What are intestinal glands also called?
crypts of Lieburkuhn
TRUE OR FALSE: the small intestine contains most of the GI tracts bacteria
False: Only gut flora in small concentrations is found in the small intestine. Most of the GI tracts bacteria is found in the colon.
Under what nervous system is the majority of the digestive system controlled?
Autonomic (only the top 1/3 of the oesophagus and last sphincter of the anus is voluntary)
TRUE OR FALSE: The gut is controlled by hormones it makes its self rather than hormones synthesised elsewhere.
True
Name three hormones associated with the digestive system.
- Secretin
- CCK
- Gastrin
What is the role of secretin?
- promotes bicarbonate ion secretion from the pancreas
- promotes bile production from the liver
- inhibits acid secretion from stomach
What is the role of gastrin?
Promotes production of HCL by parietal cells of stomach.
What is the role of CCK?
- promotes release of digestive enzyme from the pancreas
- promotes release of bile from the gall bladder
- suppresses hunger
