L49: Alimentary System Controls Flashcards
What control is the alimentary system under?
- Nervous;
- Hormones.
What type of nervous control is the alimentary system under?
- Somatic, voluntary;
- Autonomic, involuntary.
What are the two autonomic nervous systems?
- Sympathetic: fight or flight;
- Parasympathetic: rest and digest.
What hormones control the alimentary system?
- Cholecystokinin (CCK) ‘bile-sac-mover’;
- Gastrin (G-cells);
- Gastric inhibitory peptide (GIP);
- Secretin.
What does the release of CCK do?
Contracts gall bladder (bile)
What does the release of gastrin do?
- Activates parietal cells (HCl);
- Aids gastric motility.
What does the release of GIP do?
- Induce insulin secretion by the pancreas;
- Also reduce the secretion of stomach acid and motility.
What does the release of secretin do?
- Stimulate secretion from liver and pancreas;
- Reduce acid production by parietal cells and increase bicarbonate production by pancreas.
Which part of the alimentary system is under autonomic nervous control?
Middle - lower oesophagus, stomach, intestines
Which part of the alimentary system is under hormonal control?
Stomach and small intestine
Which cranial nerves control saliva secretion?
7, 9 and 1 (minor-olfaction)
Which cranial nerve detects the load on PDL from chewing?
5
Which cranial nerve innervates the oesophagus?
10
What are the 3 major phases of digestion?
- Cephalic (before food enters);
- Gastric (swallowing of food);
- Intestinal (chyme entering duodenum).
At what point is a bolus of food called chyme?
From stomach > duodenum, through pyloric sphincter i.e. once food bolus has been mixed with gastric juices and is partially digested
What stimulates the release of CCK?
The induction of acidity into the duodenum (s. intestine)
What stimulates the release of CCK?
The induction of acidity into the duodenum (s. intestine)
What stimulates the release of secretin?
The induction of acidity into the duodenum (s. intestine)
What hormones are released in the duodenum?
CCK, secretin and GIP
What hormones are released by the stomach?
Gastrin
Where are Brunner’s glands located?
Duodenum
What is the purpose of Brunner’s glands?
Produce a mucus-rich alkaline secretion to:
- Protect the lining of the small intestine from acidic chyme;
- Provide an alkaline condition for intestinal enzymes to work for absorption;
- Lubrication of intestinal walls.
What controls the flow of digestive juices (pancreatic juices and bile) in the duodenum?
Sphincter of Oddi (bile duct)
