Pyloric antrum

Pyloric antrum (antrum, lesser cul-de-sac) is the initial portion of the pyloric part of the stomach. It is near the bottom of the stomach on the left side of the pyloric sphincter, which separates the stomach and the duodenum.

It may temporarily become partially or completely shut off from the remainder of the stomach during digestion by peristaltic contraction of the prepyloric sphincter; it is demarcated, sometimes, from the second part of the pyloric part of the stomach (pyloric canal) by a slight groove.

Function
The pyloric antrum is the location of several important endocrine cells including Gastrin-producing G Cells (stimulate acid production) and the luminal-pH-sensitive population of somatostatin producing of D cells (responsible for shutting off acid secretion. There is a second hormone-sensitive population near the fundus.)

Etymology
Pylorus - lesser, atrum  - cave; cavern; hollow place with overarching foliage; cavity, hollow; tomb