Gastric Motility & Secretions. Mel & Dave (plus Poppy helped). Any errors found in this presentation are Mel’s fault, anything good thank Dave. GASTRIC ANATOMY. GASTRIC MOTILITY. Receptive Relaxation Stomach is empty and contracted initially
Mel & Dave
(plus Poppy helped)
Any errors found in this presentation are Mel’s fault, anything good thank Dave
Stomach is empty and contracted initially
Mucosa and sub-mucosa start highly folded into rugae
Food swallowed – muscle in wall of orad region relaxes
Mediated by the vagus nerve
Enteric neurons release NO and serotonin
Gastric contents remain in a relatively undisturbed state
Gastric contractions begin in body and move towards antrum
Contractions derive from two basic patterns of electrical activity
Co-ordinated contractions of smooth muscle
Powerful contraction occurs as wave reaches antrum
Pyloric sphincter closes
Co-ordinated contractile activity of stomach, pylorus and proximal small intestine
Regulated by cholecystokinin (CCK), gastrin, gastric inhibiting polypeptide (GIP) and secretin
It is important to regulate gastric motility because the duodenum cannot is not as adapted as the stomach is to food storage.
Gastric emptying is regulated in response to contents which are:
Receptors in the mucosa of the duodenum and the jejunum sense these properties and release the enteric hormones which inhibit antral contractions and/or elicit contractions of the pyloric sphincter
The hormones that cause contraction of the pyloric sphincter are cholecystokinin (CCK), gastrin, gastric inhibiting polypeptide (GIP) and secretin (this is why they regulate emptying, see previous slide!)
Stomach secretes up to 3L of gastric juice per day
The main components of gastric juice are:
These are secreted from different cells within the gastric glands of the gastric mucosa
Gastric hormones are also secreted by the gastric glands – these are responsible for controlling the secretion of gastric juice.
The gastric hormones include:
I tried to simplify the diagram given in your lectures – if this doesn’t help just stick to yours!
Also I’ve not included the specific receptors as I don’t think that’s important
Type of epithelium?