Muscle 9 Flashcards
can smooth muscle activate calcium channels without action potentials
yes through graded potentials
how does a multiunit smooth muscle generate a threshold
graded potentials because they are not electrically coupled to other cells
are multiunit smooth muscles electrically coupled
no
what gets opened when the amount of Ca in the SR is low in smooth muscle
store operated calcium
does a phasic smooth muscle or a tonic smooth muscle spend the majority of time in a contracted state
tonic
pharmacomechanical coupling occurs without
a change in membrane potential
what can a stretch of smooth muscle do
cause internal release of Ca from the SR through the RYR receptor
what m use be activated in smooth muscle? how does it get activated
myosin ATPase
phosphorylated
what do calcium ions bind to in smooth muscles
calmodulin
how many calcium ions bind to calmodulin in smooth muscle
4
what does the Ca calmodulin complex activate
myosin light chain kinase
what phosphorylates the regulatory chain
myosin light chain kinase
whats different in smooth muscle compared to the others
ATPase activity of myosin is always active in the other 2
the calcium release channel in smooth muscle sarcoplasmic reticulum that is opened by activation of a second messenger pathway is
IP3 receptor channel
what is very slow in smooth muscle
power stroke
