The Rise of Kâ12 Blended Learning | 133 NSTITUTE NNOSIGHT represents a ranking of 1 st in Santa Clara County and 5 th in California when compared to similar schools with at least 70 percent low-income students.
The heart has four chambers, two upper atria, the receiving chambers, and two lower ventricles, the discharging chambers. The atria open into the ventricles via the atrioventricular valves, present in the atrioventricular septum. This distinction is visible also on the surface of the heart as the coronary sulcus.
When your heart beats, the electrical impulses that cause it to contract follow a precise pathway through your heart. Interruption in these impulses can cause an irregular heartbeat (arrhythmia). Your heart is divided into four chambers. The chambers on each half of your heart form two adjoining pumps, with an upper chamber (atrium) and a lower chamber (ventricle). During a heartbeat, the smaller, less muscular atria contract and fill the relaxed ventricles with blood.