Gastric Secretions

HideShow resource information
  • Created by: Becca
  • Created on: 23-12-13 22:03
What are the 2 secreting regions of the stomach & where are they?
Oxyntic mucosa in the fundus & body. Pyloric gland area in the antrum. Mucosal gland cells are found in gastric pits.
1 of 11
What are the 4 cell types in the stomach & what do they produce?
Parietal cells: HCL, intrinsic factor that binds vitamin B12 to enable its absorption. Surface epithelia: mucous. Mucous neck cells: mucous. Chief cells: pepsinogen
2 of 11
HCl does not digest material. How does aid digestion?
Activation of pepsin, provides an acid medium for optimal pepsin activity, aids the breakdown of connective tissue & muscle fibres
3 of 11
What is the major digestive constituent of gastric secretions?
Pepsinogen produced by chief cells
4 of 11
What are the 3 phases of gastric secretion?
Cephalic, gastric & intestinal phases
5 of 11
Describe the cephalic phase of gastric secretion
Secretion stimulated (thought/expectation/sight/taste/chewing/swallowing) prior to food, contributes 30-50% secretions, dependent on activity of the vagus nerve (CNS involved)
6 of 11
Describe the gastric phase of gastric secretion
50-60% secretions, local vago-vagal reflexes in response to mechanical stimulation due to food in antrum (no CNS involved), stimulation of gastric release from G-cells by peptide fragments of partially digested proteins (major mechanism)
7 of 11
Describe the intestinal phase of gastric secretion
5% maybe due to circulating amino acids or gastrin
8 of 11
What are the mechanisms of gastric circulation?
Local metabolite production (prostaglandins maintain capillary network, provide enough fluid for secretions), release of vasoactive intestinal polypeptide (VIP) from local nerves causing vasodilatation
9 of 11
How is gastric secretion inhibited?
Removal of peptide fragments (no longer stimulates gastrin release). Removing food decreasing pH, pH
10 of 11
How is gastric mucosa protected from gastric secretions?
Luminal membranes are impermeable to H+, -ve feedback: pH
11 of 11

Other cards in this set

Card 2

Front

What are the 4 cell types in the stomach & what do they produce?

Back

Parietal cells: HCL, intrinsic factor that binds vitamin B12 to enable its absorption. Surface epithelia: mucous. Mucous neck cells: mucous. Chief cells: pepsinogen

Card 3

Front

HCl does not digest material. How does aid digestion?

Back

Preview of the front of card 3

Card 4

Front

What is the major digestive constituent of gastric secretions?

Back

Preview of the front of card 4

Card 5

Front

What are the 3 phases of gastric secretion?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Medicine resources:

See all Medicine resources »See all Gastrointestinal System resources »