[20 points] Indicate which of the following statements regarding smooth muscle is not correct AND briefly explain why it is incorrect. A. Activator Ca2+ (for contraction) can enter the myofilament space across the sarcolemma in response to a stimulus that does not alter the sarcolemma's membrane potential. B. Crossbridges in the "latch" state go through (finish, if they are attached) their cycle more slowly than crossbridges that are phosphorylated. C. Single-unit smooth muscle is more densely innervated than is multi-unit smooth muscle. D. Ca2+ in the myofilament space can be extruded across the sarcolemma via a secondary active transport mechanism.
