7 How Do We Stomach Our Food?. Flashcards
What is the function of rugae in the stomach?
To quickly channel liquids that are ready to be digested
What type of reflex is the receptive relaxation?
Vago-vagal reflex
Involuntary reflex involving the vagus nerves
Describe the process of receptive relaxation
Food distends Oesophagus which is detected by mechanoreceptors in muscularis externa
Relay this info to brain stem via vagus
Motor signal sent to myenteric plexus
Which secretes vasoactive intestinal peptide VIP
Smooth muscles in oesophagus orad and corpus relax
What does the cardia secrete to lubricate food?
Mucus
What does surface epithelial cells secrete?
Mucus, HCO3
What to enterochromaffin like ECL cells secrete?
Histamine
What do D cells secrete?
Somatostatin
Proliferating cells are located where in the stomach?
Neck of the gland lumen
Why are parietal cells packed with mitochondria?
Supports high levels of cell respiration and energy required for pumping acid into the stomach lumen which is already high in acid
What structures fuse when the parietal cell is activated to create a large surface area for acid secretion?
Intracellular canaliculi and tubulovesicles
How do parietal cells secrete HCL?
Carbonic acid made by carbonic anhydrase
Releases H+ from cell
K moves in to move H+ out of
K channels open to help with this process
Apical Cl- channels also open - to help cells remain electronically neutral
Sodium potassium pumps from blood help enhance K+ available in the cell
What phase of gastric acid secretion is triggered by thought, sight, smell, taste of food?
Cephalic
What causes the gastric phase of acid secretion?
Distention of stomach and food in stomach
What is the major phase of acid secretion?
Gastric
What phase of gastric acid secretion is caused by distention/food in duodenum?
Intestinal