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Monogastric Stomach - Anatomy & Physiology (view source)
Revision as of 17:44, 10 December 2010
, 17:44, 10 December 2010no edit summary
'''Sympathetic''' fibres run with the arteries. '''Parasympathetic''' fibres from the '''vagus''' nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) are within the two vagal trunks. In the '''proximal''' region of the stomach, vagal stimulation '''suppresses''' muscular contraction (VIP); In the '''distal''' region, vagal stimulation '''increases''' muscular activity (ACh).
'''Sympathetic''' fibres run with the arteries. '''Parasympathetic''' fibres from the '''vagus''' nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) are within the two vagal trunks. In the '''proximal''' region of the stomach, vagal stimulation '''suppresses''' muscular contraction (VIP); In the '''distal''' region, vagal stimulation '''increases''' muscular activity (ACh).
==Histology==
[[Image:Glandular Stomach Histology Dog.jpg|thumb|right|150px|Glandular Stomach Histology Dog- Copyright RVC 2008]]
*Columnar epithelium
*Folded mucosa forming longitudinal rugae
*Invaginations called gastric pits which are continuous with gastric glands
*The 4 layers of the stomach wall are:
**Serosa/adventitia
**Tunica muscularis
**Submucosa
**Mucosa
*Chief (zygomatic) cells secreting pepsinogen
**Secreted in response to vagus and gastrin
**Basophilic
**More abundant in base of glands
**Pepsinogen unfolds and cleaves itself (autocatalyses) in response to hydrochloric acid
**Only active in acidic envrionments
[[Image:Fundic region of glandular stomach.jpg|thumb|right|150px|Fundic Region of Glandular Stomach (Parietal and Chief cells)- Copyright RVC 2008]]
*Goblet cells secreting mucous
**Protects against autodigestion
*Parietal (oxyntic) cells secreting hydrochloric acid in gastric pits
**Aids digestion
**Activates gastric enzymes, e.g. pepsinogen to pepsin
**Kills microorganisms and enzymes that enter with food
**Secreted in response to vagus or pepsin
**Large, pyramid shaped
**More abundant in upper region of glands
*Gastrin from pyloric G cells
*Somatostatin from pyloric D cells
*Histamine from Enterochromaffin-like cells (ECL cells)
[[Image:Lamina muscularis 3 regions.jpg|thumb|right|150px|Lamina Muscualris 3 Regions - Copyright RVC 2008]]
*3 layers of lamina muscularis: the outer longitudinal, middle circular and inner oblique.
*Glands are short, coiled, branched tubular. Need to be replaced due to wear and tear. Only in mucosal layer.
*Cardia is a narrow muscle strip
*Pyloric sphincter is thickened tunica muscularis from the middle circular smooth muscle layer
*In fundic region, tunica muscularis is thinner, glands are straight and gastric pits are shallow. Abundance of parietal and cheif cells in gland.
*In pyloric region, tunica muscularis is thicker, glands are coiled and gastric pits are deep.
*Lymphatic vessels are present in the submucosa
==Digestive Enzymes==
==Digestive Enzymes==
Click here for [[Control of Feeding - Anatomy & Physiology|Control of Feeding]].
Click here for [[Control of Feeding - Anatomy & Physiology|Control of Feeding]].
'''Video links:'''
'''Video links:'''