Gastrointestinal Motility Flashcards
Listen to the ending of the lecture recording to know the extra things to study
The nervous systems that control the GIT
The enteric nervous system
Autonomic (Sympathetic and Parasympathetic) nervous system
The Central Nervous system
The two plexuses that make up the enteric nervous system
Myenteric plexus
Meissner’s plexus
The vagal afferents pass through which ganglion to the brain?
Nodose ganglion
Spinal afferents pass through which ganglion to the brain
Dorsal root ganglion
What are the efferent parasympathetic nerve fibers to the gut?
Vagal nerves
Pelvic nerves
The vagal nerves come from which ganglion to the gut?
Dorsal motor nucleus of vagus
What are the efferent sympathetic nerve fibers to the gut?
Celiac nerve
Superior mesenteric
Inferior mesenteric
The efferent sympathetic fibers originate from which ganglia?
Prevertebral ganaglia
Which neurotransmitter excites both myenteric and submucosal plexuses?
Acetylcholine
Which neurotransmitter inhibits myenteric plexus?
Nitric oxide
Which gut hormone inhibits the myenteric plexus?
Vasoactive intestinal peptide (VIP)
Which gut hormone excites the myenteric plexus?
Substance P
The ratio of actin to myosin in GI smooth muscles
15:1
The two types of smooth muscles based on how the muscle fibers are connected and how they contract
Unitary
Multiunit
Unitary smooth muscles are electrically coupled by
Gap junctions
The function of essential light chains on myosin
They stabilize the myosin structure
The function of regulatory light chains(RLCs) on myosin
They activate myosin when phosphorylated
What kinase phosphorylates RLCs on myosin
Myosin light chain kinase
The two actin associated proteins that inhibits myosin ATPase activity
Caldesmon
Calponin
What inhibits the activity of caldesmon and calponin?
Increased Ca2+ - calmodulin concentrations
Phosphorylation by myosin light chain kinase( MLCK)
Caveolae on the sarcolemma are rich in what type of protein channels?
L-type Ca2+ channels
Name the two types of Ca2+ channels on the sarcoplasmic reticulum
Ca2+ induced Ca2+ release channels
IP3 gated Ca2+ channels
Which enzyme dephosphorylates regulatory light chains to cause smooth muscles to relax?
Myosin light chain phosphatase (MLCP)
A state in which dephosphorylated myosin remains attached to actin for prolonged period of time is called
The latch system
The two types of smooth muscle contractions
Phasic contractions
Tonic contractions
Phasic contraction : periodic contractions followed by relaxation
Tonic contractions : maintained contraction without relaxation
Orad region of stomach: Fundus + proximal body
What do slow waves in GI smooth muscles represent?
Changes in resting membrane potential
What are the pacemaker cells in smooth muscles called?
Interstitial Cells of Cajal
