Lopez DSA Flashcards
Which cells are thought to be a cause of the slow waves in the GI tract?
Interstitial cells of Cajal
Where do spike potentials normally happen in the Gi tract?
about 40 mV
List the order of a events for a muscle contraction starting with a slow wave.
slow wave, spike potentials, then THEY excite the muscle contraction
what molecule causes depolarization in the GI smooth muscle?
Ca and Na
-they are slower, that’s why the AP”s are longer
What are factors that will depolarize the membrane?
strecth, Ach from parasympathetics, and specific GI hormones
What make s the membrane potential more negative?
NE or E, sympathetic stimulation
What causes smooth muscle contraction?
The entry of calcium ions
What causes Ca ions to enter?
NOT the slow waves, it’s the spike potentials
What is tonic contraction?
when it’s contracted all the time
What are the 3 causes of tonic contraction?
repetitive spike potentials, hormones that bring about continuous partial depolarization, and the continuous entry of Ca ions into the interior of the cell (not because of changes in membrane potential
What are the plexuses of the enteric nervous system?
Auerbach’s and Meissner’s
