5.3.4. Overview of the Stomach - Pepsinogen and Gastric Mucus Flashcards
Where is Pepsinogen Released from?
The Chief Cells of the Gastric Glands
Do the Chief Cells lie Superficial or Deep to the Mucous Cell Neck?
Deep
Do the Chief Cells lie Superficial or Deep to the Parietal Cells?
Deep
What is Pepsinogen?
An inactive Precursor of Pepsin
What is another term used to describe an inactive pre-cursor?
A Zymogen
What is Pepsin responsible for?
The Breaking down or Proteins into smaller Peptides
What is the Advantage of storing Pepsinogen, as a Zymogen?
It prevents Cellular Digestion
What are the mechanisms for control of Pepsin Secretion?
These run parallel to Gastric Acid Secretion:
- The increase in Vagal Nerve Activity, increasing the Acetylcholine acting on the Chief Cells
- The increase in Gastrin acting on the Chief Cells
- The increase in Histamine acting on the Chief Cells
What activates Pepsinogen to become Pepsin?
The Hydrogen Ion from the Gastric Acid secreted
Needs to be a pH less than 3
What is Gastric Mucous produced by?
- The Surface Epithelial Cells
2. The Mucous Neck Cells
What is the function of the Gastric Mucous?
It has a Cytoprotective Role
What is the Cytoprotective Role of the Gastric Mucous?
- It Protects the Mucosal Surface from Mechanical Injury
2. It releases Bicarbonate which Neutralizes the Gastric Acid and Pepsin - this prevents self-digestion
