But if youâre not a boxer trying to go pro, how much do you need to stay fit or lose weight? Step on a scale and be honest with yourself about your activity level. Men who work out for 45 minutes three to five days a week need about 0.45 gram per pound; women with the same activity level need 0.35 gram per pound. So an 180-pound guy who works out regularly needs about 80 grams of protein a day. For a 140-pound woman, that translates to nearly 50 grams of protein daily. Now, for the fun part: eating! The fewer calories you consume, the greater the proportion of calories that should come from protein, says Donald Layman, PhD, a professor emeritus of nutrition at the University of Illinois.
Sinoatrial Node (SA) node. patch of modified cardiocytes in the right atrium, just under the epicardium near the super venae cava. this is the pacemaker that initiates each heartbeat and determines heart rate. signals from this node spread throughout the atria.
Artificial cardiac pacemaker. A pacemaker (or artificial pacemaker, so as not to be confused with the heart's natural pacemaker) is a medical device which uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart. The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system.