In which one of the following pairs the two items mean one and the same thing?
In which one of the following pairs the two items mean one and the same thing?
Malleus - anvil
SA node - pacemaker
Leucocytes - lymphocytes
Haemophilia - blood cancer
Solution
SA node or sino-atrial node is known as the pacemaker of heart because the cells in the SA node contract the most number of times per minute and because each wave of excitation begins here and acts as the stimulus for the next wave of excitation.