Changes

[[Image:Cephalic phase of secretion diagram.jpg|thumb|right|250px|Cephalic phase of secretion - Copyright RVC 2008]]

[[Image:Cephalic phase of secretion diagram.jpg|thumb|right|250px|Cephalic phase of secretion - Copyright RVC 2008]]

This pahse is an unconditioned reflex. It is stimulated by the sight, smell and taste of food. It involves the Vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) and parasympathetic fibres that synapse in the submucosal plexus. [[Endocrine System - Gut - Anatomy & Physiology|Gastrin]] is secreted from the endocrine cells in the pyloric mucosa. Postganglionic fibres activate chief, parietal, mucous and G cells. Histamine is secreted from paracrine action. There is an increase in [[Monogastric Stomach - Anatomy & Physiology|stomach]] motility by release of hydrochloric acid and pepsinogen. It is a short phase and overlaps with the gastric phase of secretion. It is inhibited by stress and increased by aggression.

This pahse is an unconditioned reflex. It is stimulated by the sight, smell and taste of food. It involves the Vagus nerve ([[Cranial Nerves - Anatomy & Physiology|CN X]]) and parasympathetic fibres that synapse in the submucosal plexus. [[Gut Endocrine Function - Anatomy & Physiology|Gastrin]] is secreted from the endocrine cells in the pyloric mucosa. Postganglionic fibres activate chief, parietal, mucous and G cells. Histamine is secreted from paracrine action. There is an increase in [[Monogastric Stomach - Anatomy & Physiology|stomach]] motility by release of hydrochloric acid and pepsinogen. It is a short phase and overlaps with the gastric phase of secretion. It is inhibited by stress and increased by aggression.

[[Image:gastric control of secretion diagram.jpg|thumb|right|250px|Gastric control of secretion - Copyright RVC 2008]]

[[Image:gastric control of secretion diagram.jpg|thumb|right|250px|Gastric control of secretion - Copyright RVC 2008]]

===Gastric===

===Gastric===

Chemical and mechanical receptors in the [[Monogastric Stomach - Anatomy & Physiology|stomach]] respond to stretch and chemical stimulation by an increase in the pH of gastric contents. It is a response to undigested materials, especially proteins. Histamine and [[Endocrine System - Gut - Anatomy & Physiology|gastrin]] are released. It is a negative feedback loop by sympathomimetic somatostatin released by paracrine method to inhibit [[Endocrine System - Gut - Anatomy & Physiology|gastrin]] secretion (when pH falls below 3). The submucosal and myenteric plexuses are activated in vagus reflex arcs causing the postganglionic release of ACh at parietal cells. The neural response and presence of peptides in chyme stimulates gastrin release. Parietal and chief cells stimulate via gastrin acting in the bloodstream. It is a long response.

Chemical and mechanical receptors in the [[Monogastric Stomach - Anatomy & Physiology|stomach]] respond to stretch and chemical stimulation by an increase in the pH of gastric contents. It is a response to undigested materials, especially proteins. Histamine and [[Gut Endocrine Function - Anatomy & Physiology|gastrin]] are released. It is a negative feedback loop by sympathomimetic somatostatin released by paracrine method to inhibit gastrin secretion (when pH falls below 3). The submucosal and myenteric plexuses are activated in vagus reflex arcs causing the postganglionic release of ACh at parietal cells. The neural response and presence of peptides in chyme stimulates gastrin release. Parietal and chief cells stimulate via gastrin acting in the bloodstream. It is a long response.

[[Image:Intestinal control of secretion diagram.jpg|thumb|right|250px|Intestinal control of secretion - Copyright RVC 2008]]

[[Image:Intestinal control of secretion diagram.jpg|thumb|right|250px|Intestinal control of secretion - Copyright RVC 2008]]

===Intestinal===

===Intestinal===

Chyme in the [[Duodenum - Anatomy & Physiology|duodenum]] inhibits acid secretion and motility by decreasing the [[Monogastric Stomach - Anatomy & Physiology|stomach]] distension and increasing the stretch of the [[Duodenum - Anatomy & Physiology|duodenum]] leading to the enterogastric reflex. A drop in pH below 4.5 causes release of secretin which inhibits parietal and chief cells and stimulates buffer release from the [[Pancreas - Anatomy & Physiology|pancreas]]. Chyme causes the release of secretin, [[Endocrine System - Gut - Anatomy & Physiology|GIP]] and [[Endocrine System - Gut - Anatomy & Physiology|CCK]] decreasing gastric sectretions and motility.

Chyme in the [[Duodenum - Anatomy & Physiology|duodenum]] inhibits acid secretion and motility by decreasing the [[Monogastric Stomach - Anatomy & Physiology|stomach]] distension and increasing the stretch of the [[Duodenum - Anatomy & Physiology|duodenum]] leading to the enterogastric reflex. A drop in pH below 4.5 causes release of secretin which inhibits parietal and chief cells and stimulates buffer release from the [[Pancreas - Anatomy & Physiology|pancreas]]. Chyme causes the release of secretin, [[Gut Endocrine Function - Anatomy & Physiology|GIP]] and [[Gut Endocrine Function - Anatomy & Physiology|CCK]] decreasing gastric sectretions and motility.

[[Image:Pancreatic control of secretion diagram.jpg|thumb|right|250px|Pancretic control of secretion - Copyright RVC 2008]]

[[Image:Pancreatic control of secretion diagram.jpg|thumb|right|250px|Pancretic control of secretion - Copyright RVC 2008]]

===Pancreatic===

===Pancreatic===

Involves [[Endocrine System - Gut - Anatomy & Physiology|CCK]], secretin and [[Endocrine System - Gut - Anatomy & Physiology|Gastrin]]. Parasympathetic stimulation during cephalic and gastric phases. Negative feedback occurs from paracrine sympathomimetics (somatostatin and enkephalins).

Involves [[Gut Endocrine Function - Anatomy & Physiology|CCK]], secretin and [[Gut Endocrine Function - Anatomy & Physiology|Gastrin]]. Parasympathetic stimulation during cephalic and gastric phases. Negative feedback occurs from paracrine sympathomimetics (somatostatin and enkephalins).

===Biliary===

===Biliary===

[[Endocrine System - Gut - Anatomy & Physiology|CCK]] empties the [[Gall Bladder - Anatomy & Physiology|gall bladder]] and secretin stimulates hydrogencarbonate ions from the bile duct.

[[Gut Endocrine Function - Anatomy & Physiology|CCK]] empties the [[Gall Bladder - Anatomy & Physiology|gall bladder]] and secretin stimulates hydrogencarbonate ions from the bile duct.

===Small Intestinal===

===Small Intestinal===

Involves secretin, [[Endocrine System - Gut - Anatomy & Physiology|GIP]] and [[Endocrine System - Gut - Anatomy & Physiology|Gastrin]]. Contolled by vagal tone and the parasympathomimetic reflex.

Involves secretin, [[Gut Endocrine Function - Anatomy & Physiology|GIP]] and [[Gut Endocrine Function - Anatomy & Physiology|Gastrin]]. Contolled by vagal tone and the parasympathomimetic reflex.

==Neuroendocrine Regulation of Feeding==

==Neuroendocrine Regulation of Feeding==