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.
Normally we figure out someone's age with current date subtracting the given birth date. So does it in Excel. Step 1: Enter current date in a blank cell, such as 2016/4/7 in Cell B2. Step 2: In another blank cell (says cell C2), enter the formula =INT((B2-A2)/365), and press the Enter key.