Changes

The monogastric stomach has a columnar epithelium. The folded mucosa of the stomach forms a '''longitudinal rugae'''. The folds form invaginations called '''gastric pits''' which are continuous with gastric glands.

The monogastric stomach has a columnar epithelium. The folded mucosa of the stomach forms a '''longitudinal rugae'''. The folds form invaginations called '''gastric pits''' which are continuous with gastric glands.

''Layers of the stomach''

===Layers of the stomach===

The 4 layers of the stomach wall are:  

The 4 layers of the stomach wall are:  

'''1.Serosa/adventitia'''

'''1.Serosa/adventitia'''

'''2.Tunica muscularis'''

'''2.Tunica muscularis'''

'''3.Submucosa'''

'''3.Submucosa'''

'''4.Mucosa'''

'''4.Mucosa'''

There are 3 layers of '''muscularis''': the outer longitudinal, middle circular and inner oblique. The '''pyloric sphincter''' is thickened tunica muscularis from the middle circular smooth muscle layer. In the '''fundic region''', the tunica muscularis is thinner, the glands are straight and the gastric pits are shallow. There is also an abundance of parietal and cheif cells in the gland. In the '''pyloric region''', the tunica muscularis is thicker, the glands are coiled and the gastric pits are deep. The '''cardia''' is a narrow muscle strip. The lymphatic vessels are present in the submucosa.

There are 3 layers of '''muscularis''': the outer longitudinal, middle circular and inner oblique. The '''pyloric sphincter''' is thickened tunica muscularis from the middle circular smooth muscle layer. In the '''fundic region''', the tunica muscularis is thinner, the glands are straight and the gastric pits are shallow. There is also an abundance of parietal and cheif cells in the gland. In the '''pyloric region''', the tunica muscularis is thicker, the glands are coiled and the gastric pits are deep. The '''cardia''' is a narrow muscle strip. The lymphatic vessels are present in the submucosa.

''Cell types''

===Cell types===

The stomach contains basophilic '''chief (zygomatic) cells''' that secrete '''pepsinogen''' in response to vagus nerve stimulation and gastrin release. Pepsinogen unfolds and cleaves itself (autocatalyses) in response to hydrochloric acid, therefore only in acidic envrionments.

The stomach contains basophilic '''chief (zygomatic) cells''' that secrete '''pepsinogen''' in response to vagus nerve stimulation and gastrin release. Pepsinogen unfolds and cleaves itself (autocatalyses) in response to hydrochloric acid, therefore only in acidic envrionments.