PHYS Introduction & Neuronal Control of the Gut - Week 3 Flashcards
Name of the lining of the small intestine’s lumen.
Mucosa.
Circular layer of spindle-shaped, smooth muscle cells are located where in the small intestine
Inner layer of smooth muscle.
Function of circular smooth muscle in small intestine.
Contraction -> constriction.
Longitudinal layer of spindle-shaped, smooth muscle cells are located where in the small intestine.
Outer layer of smooth muscle.
Function of the longitudinal smooth muscle in the small intestine.
Contraction -> shortening.
How do action potentials travel through smooth muscle of small intestine?
Via pores in gap junctions.
Describe oesophageal peristalsis as an example of gut motility.
Stretch sensitive receptors on inner mucosal lining of oesophagus -> peristalsis.
Constriction, due to circular smooth muscle cells, leads to narrowing of oesophagus behind bolus.
Shortening, due to longitudal smooth muscle cells, leads to shortening of oesophagus in front of bolus.
2 types of enteric nerve plexes
- Myenteric plexus (@ btw circular & longitudinal layers of smooth muscle) – controls motility
- Submucosal plexus (@ discrete regions of submucosal connective tissue) – secretions & absorption of nutrients
If enteric neuron releases ACh, then excitatory/inhibitory and result…
E. Increased motility & secretions.
If enteric neuron releases NO, then excitatory/inhibitory and result…
I. Smooth muscle cell relaxation.
Function of muscularis layer.
Increased motility.
Function of submucosa.
Increased secretions.
Structures contained in the submucosa.
Glands & submucosal plexus.
Structures contained in muscularis externae.
2 x layers of smooth muscle cells & myenteric plexus.
State whether enteric nerves are autonomous or not?
Can be autonomous, but are usually modified by autonomic nerves.
