Smooth Muscle Propagation

Question 1

What do slow oscillations in the membrane potential reflect?

Answer 1

Activity of electrogenic pumps in cell membrane

Question 2

What can tonic contractile activity be related to?

Answer 2

Value of membrane potential in absence of APs

Question 3

What is pharmaco-mechanical coupling?

Answer 3

Changes in force produced by addition or removal of drugs or hormones that have no significant effect on membrane potential

Question 4

What do the lack of striations enable smooth muscle to do?

Answer 4

Smooth muscle cells can generate normal active tension over a very wide range of changes in length

Question 5

What are smooth muscle’s variable force-velocity
relationships determined by?

Answer 5

Level of ca2+ stimulated cross-bridge phosphorylation

Question 6

What are maximal shortening velocities with no load dependent on?

Answer 6

Cross-bridge phosphorylation by MLCK

Question 7

What does an actin filament lattice consist of?

Answer 7

Actin filaments attached to dense plaques and dense bodies

Question 8

What does a contractile unit consist of?

Answer 8

Myosin filament sandwiched between 2 actin filaments and associated dense bodies/plaques