Stimulation of the vagus nerve will make the heart beat

Heart rate is increased by all the following except:

Read the following statements:
$I$ - Increased heart rate.
$II$ - Increased ventricular contraction force.
$III$ - Decreased cardiac efficiency.
$IV$ - Increased cardiac efficiency.
$V$ - Decreased heart rate.
$VI$ - Decreased conduction speed of action potential.
Categorize the given statements into Sympathetic and Parasympathetic nervous systems.
Sympathetic Nervous System $\quad$ Parasympathetic Nervous System

When the normal heart of a man is injected with a physiological concentration of adrenaline, it shows:

During high blood pressure,the regulation of circulation and heart rate is controlled by which of the following centers?

Select the correct option regarding the regulation of cardiac activity.