Question 21
An andrenergic ligand bonds to Beta 2 receptors on smooth muscleof bronchioles. Through the action of the intracellular secondmessenger cAMP protein kinase is activated which phosphorylates andinactivates MLCK. How does this impact bronchiole diameter?
P-MLCK can't phosphorylate myosin light chains in myosin heads,causing bronchodilation
P-MLCK will activate myosin heads to form crossbridges,resulting in bronchdilation
P-MLCK activates ATPase on myosin heads causingbronchoconstriction
Question 22
Which myofilament in smooth muscle makes up the Dark Bands inskeletal muscle?
Only actin
Myosin and overlapping actin
Only myosin
Question 23
About _________ percentage of energy (ATP) consumed by skeletalmuscle is used by myosin ATPase on myosin heads forcontraction.
30
50
99.9
70
