The gastric folds (or gastric rugae) are coiled sections of tissue that exist in the mucosal and submucosal layers of the stomach.[1] They provide elasticity by allowing the stomach to expand when a bolus enters it. These folds stretch outward through the action of mechanoreceptors, which respond to the increase in pressure.[2] This allows the stomach to expand, therefore increasing the volume of the stomach without increasing pressure.[2] They also provide the stomach with an increased surface area for nutrient absorption during digestion.[2] Gastric folds may be seen during esophagogastroduodenoscopy or in radiological studies.[3][4]
Layers
The gastric folds consist of two layers:
Mucosal layer – This layer releases stomach acid. It is the innermost layer of the stomach.[5] It is affected by the hormone histamine, which signals it to release hydrochloric acid (HCl).
Sub-mucosal layer – This layer consists of different vessels and nerves, ganglion neurons, and adipose tissue. It is the second layer of the stomach and supports the mucosa.[6]