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Monogastric Stomach - Anatomy & Physiology (view source)
Revision as of 13:26, 4 July 2008
, 13:26, 4 July 2008no edit summary
*Stomach split into regions: cardia, fundic, body and pyloric parts
*Stomach split into regions: cardia, fundic, body and pyloric parts
*Entire stomach motile
*Entire stomach is motile
*pH 0.9 to 1.5
*pH 0.9 to 1.5
*The larger part of the stomach lies to the left of the midline, under cover from the ribcage and contacts the liver and diaphragm. The [[Oesophagus - Anatomy & Physiology|oesophagus]] opens into it at the cardiac sphincter.
*The smaller part of the stomach has thicker walls and passes to the right of the midline into the duodenum at the pyloric sphincter.
*The fundus is a blind dome rising above the cardia
*The body extends from the cardia ventrally
*The pyloric part is on the right divided into a more muscular and a less muscular half
*The serosa (external peritoneum) covers the entire organ
*Contractions start near the cardia and spread distally, accelerating and becoming more vigorous as they reach the pylorus region.
*The pyloric sphincter is open for 1/3 of the time during contractions
*The empty stomach lies completely within the rib cage and does not contact the abdominal floor. Little secretion is produced and only small peristaltic contractions occur.
*Once food is offered or anticipated secretions begin
*Columnar epithelium
*Columnar epithelium
*Folded mucosa
*Folded mucosa forming longitudinal rugae
*Invaginations called gastric pits which are continuous with gastric glands
*Invaginations called gastric pits which are continuous with gastric glands
*In pyloric region, tunica muscularis is thicker, glands are coiled and gastric pits are deep.
*In pyloric region, tunica muscularis is thicker, glands are coiled and gastric pits are deep.
*Lymphatic vessels are present in the submucosa
*The gastric arteries supply the lesser curvature of the stomach
*The gastric arteries supply the lesser curvature of the stomach
*The numerous veins join the portal vein
==Innervation==
*Sympathetic fibres run with the arteries
*Parasympathetic from the vagus nerve (CN X) are within the two vagal trunks. In the proximal region of the stomach, vagal stimulation suppresses muscular contraction (VIP) and in the distal region, vagal stimulation increses muscular activity (ACh).