Fill in the Correct Labels for the Following Figure Using

Q36: Cardiac muscle fibers are joined at their

Q37: The condition in which the heart rate

Q38: The cardiac muscle becomes _, or lacking

Q39: _ increases heart rate.<br>A) Relaxation<br>B) Norepinephrine<br>C) Acetylcholine<br>D)

Q40: The _ valve guards the passageway between

Q42: Based on what you have learned about

Q43: The _, or pacemaker of the heart,

Q44: Fill in the correct labels for the

Q45: According to _ law of the heart,

Q46: Sensory receptors in blood vessels and in