Question

The .......... is a small, flattened and strip of muscle fibre of .......... size it is situated in the upper lateral wall of .......... atrium :-
(1) SA node, 0.3 mm, Left
(2) AV node, 0.3 mm, Right
(3) SA node, 0.3 mm, Right
(4) AV node, 0.3 mm, Left

Answer 1

The sino-atrial node (SA node) is a small, flattened and ellipsoid strip of muscle fibre of 0.3 mm size, situated in the upper lateral wall of the right atrium. Thus, the correct answer is 3