Smooth Muscle Flashcards
visceral smooth muscle differs from skeletal muscle in that it responds to ____
stretch
calmodulin is most closely related to ____ structurally and functionally
troponin C
delayed onset, long duration and greater force of contraction generated by smooth muscle compared to skeletal muscle result from…
slower cycling rate of myosin cross-bridges
what is the mechanism responsible for tracheal smooth muscle relaxation?
- stimulation of adenylate or guanylate cyclase (G-reactive proteins)
- all vasodilators activate myosin light chain phosphatase
smooth muscle contraction is terminated by…
dephosphorylation of myosin light chain
smooth muscle that exhibits rhythmical contraction without external stimuli also exhibits…
intrinsic pacemaker wave activity
the increase in Ca sensitivity in the steady state under normal conditions is attributable to ____
myosin light chain phosphatase (MLCP)
what are the differences in the actin of smooth muscle compared to skeletal muscle?
no troponin or tropomyosin
what acts like the Z line in smooth muscle?
dense bodies (attachments for actin)
what is the ratio of actin to myosin in smooth muscle?
5:1 to 10:1
what acts like T-tubules in smooth muscle?
caveoli
regulation of smooth muscle contraction is ____ based
myosin
smooth muscle contraction is dependent on influx of ____
Ca++
