Body Fluids and Circulation Question 77
77. Contraction of the ventricle in the heart begins by the command from
(a) Chordae tendinae
(b) S.A. node
(c) Purkinje fibres
(d) A. V. node
Show Answer
Answer : b
Hints & Solutions
(b) SA is the site of generation of the rhythmic cardiac impulse. AV node is a compact mass of myogenic fibres which receives impulse from SA node and transmits it to ventricles. Purkinje fibres are in contact with the contractile muscles of the ventricular walls. Chordae tendinae are the muscles which keep the AV valves in position. Purkinje fibers are part of the specialized conduction network of the heart that ensures that the wave of excitation spreads rapidly and almost synchronously to the ventricular muscle mass.
