GI Motility Flashcards
Which muscles are due to GI motility
Smooth and skeletal muscle
How many types of muscle contraction are there, and what are they?
Circular, lumen = narrower and larger
Longitudinal, lumen = shorter and fatter
Muscularis, change in absorptive and secretory area of mucosa
Where is the enteric nervous system located?
In the ganglia in the myenteric and submucous plexus
Which nuerons are in the enteric nervous system?
Sensory
Interneurones
Effector
In the parasympathetic system what do the preganglionic fibres do?
Release ACh, and synapse with post-ganglionic neurones within the ENS
What are the excitatory influences of the parasympathetic system?
Increased gastric, pancreatic and small intestinal secretion
Increased blood flow
And increased smooth muscle contraction
What are the inhibitory influences of the parasympathetic system ?
Relaxation of some sphincters, receptive relaxation of stomach
Where do the preganglionic fibres in the sympathetic nervous system synapse?
In the prevertebral ganglia
What inhibitory influence does the sympathetic system have?
Decreased motility, secretion and blood flow
Which nerves modulate spontaneous activity in smooth muscle?
Intrinsic and extrinsic nerves
Where does spontaneous electrical activity occur at in the smooth muscle?
As slow waves in the stomach, small intestine and large intestine
What are interstitial cells of Cajal? (ICCs)
Pacemaker cells
Where are ICCs located?
Between longitudinal and circular muscle layers in submucos
Why is the slow wave amplitude important?
This can trigger an action potential which results in a contraction
What is BER
basic electrical rhythm, determined by slow waves
