A-V Valves Open; Semilunar Valves Closed. This is the first phase of the cardiac cycle. It is initiated by the P wave of the electrocardiogram (ECG), which represents electrical depolarization of the atria. Atrial depolarization initiates contraction of the atrial musculature.
Community Q&A. You can calculate age on Excel for a many applications by combining an undocumented function and the date format for cells. Microsoft Excel internally stores dates as serial numbers, which is the number of days a date is from Jan. 1, 1900.
=(YEAR(NOW())-YEAR(A2)) Gives the age of person, 2 between today's date and the birthdate in A2. This example uses the YEAR function and NOW function. If cell doesn't display as a number, make sure it is formatted as a number or General. Learn how to format a cell as a number or date. =YEAR(NOW())-1960.