Question

Which of these statements concerning cardiac muscle is not true?

a. Cardiac muscle behaves as a single motor unit (all fibers contract at about the same time)

b. Cardiac muscle has a relatively short refractory period

c. Cardiac muscle is involuntary

d. Some cardiac muscle fibers can spontaneously depolarize

e. All of the above are true

Answer 1

b. Cardiac muscle has a relatively short refractory period