Question

a) name the 4 layers of the stomach and list their functions

b) names 2 things found in gastric juice and explain what stimulates it to be released

Answer 1

a) They are:

1.- Mucosa. A very active tissue since it is the layer that contains the acid and enzyme's producing glands. Its function is to produce the substances needed for digestion

2.- Submucosa. This layer locates under the mucosa. It plays the role of providing the mucosa with the requirements: phsycial support and bloos supply

3.- Muscle layer. This layer is completely made of smooth muscle, its function is to produce the necessary movements for correct digestion, specially the transport of the alimentary bolus from the stomach to the small intestine

4.- Serosa. Like all the other serosa tissues in the body, it is a layer that separates this organ from any other one, it has structural functions.

b) Let's choose some of the most characteristics ones: hydrochloric acid and pepsinogen. The first one provides the environment for the gastric enzymes to correctly work, it actually aids in the transformation of pepsinogen into functional pepsin, it also provides desinfection. Pepsin is the enzyme in charge of protein cleaving, it cut the amino acidic bonds to turn proteins into smaller molecules.

The signaling for the secretion of both is the same, nervous cells send gastrin and acetylcholine to give the order of these gastric secretion, and indirectly histamine too. When the cells in the mucosa receive this signal they start to release hydrochloride acid and pepsinogen.