Motility in the GI tract
Transmitters:
Intrinsic nervous system
o Excitatory
ACh
Substance P
o Inhibitory
Vasoactive intestinal peptide (VIP)
NO
Extrinsic nervous system
o Parasympathetic
ACh
o Sympathetic
NA
Two types of muscle contraction:
Phasic – majority of movements are phasic these are short lasting
contractions (seconds)
Tonic – used in reservoir function, contraction for longer periods
(minutes to hours)
SM contraction:
activation of SM:
Transmitters:
Intrinsic nervous system
o Excitatory
ACh
Substance P
o Inhibitory
Vasoactive intestinal peptide (VIP)
NO
Extrinsic nervous system
o Parasympathetic
ACh
o Sympathetic
NA
Two types of muscle contraction:
Phasic – majority of movements are phasic these are short lasting
contractions (seconds)
Tonic – used in reservoir function, contraction for longer periods
(minutes to hours)
SM contraction:
activation of SM:
