pack Flashcards
What are the three types of cells found in the gastric glands?
mucus neck cells
Chief (Peptic) cells
Parital (Oxyntic) Cells
Whatdo the mucous neck cells secrete and what is the purpose of this secretion?
secret mainly mucus but also some pepsinogen
* sufficient mucus secretion is required for adequate protection of the stomach lining
from gastric acid
A decrease in what increases the chance of developing stomach ulcers?
A decrease in mucous secretions from mucous neck cells
What do the cheif cells secrete
secret large quantities of pepsinogen
What activates pepsinogen?
HCL turns it into pepsin
What do the Pariteal cells secrete
secret hydrochloric acid and intrinsic factor
What is the job of intrinsic factor?
Helps with the absorption of B12
Fill
What nerve mediates secretion of gastic acid during the cephalic phase?
Vagus nerve
What are the mechansims that allow gastric acid to be secreated during the cephalic phase?
1 direct stimulation of parital cells
2 hormonal stimulation via gastrin
What are the mechansims that allow gastric acid to be secreated during the gastric phase?
There are 3 mechanisms in this phase;
1. Reflex - vago-vagal and enteric reflexes (distention)
2. Gastrin
3. Paracrine mechanisms
What type of cells stimulate histamine secretion?
ECL (Enterochromaffin like) cells
What does histamine do and how does it do it?
It stimulates HCL secretion by binding to pariteal cells via H2 receptors
What stimulates the ECL cells to release histamine?
Gastrin and parasympathetic
What type of channels exist in the apical and basolateral membranes of parital cells?
Apical: H+, k+ ATPase exchanger, Cl- channels
Basolateral: Na+, K+ Atpase exchanger
HCO3-,Cl- exchanger
