AP BIOLOGY

Detailed explanation-1: -The circulatory system (cardiovascular system) pumps blood from the heart to the lungs to get oxygen. The heart then sends oxygenated blood through arteries to the rest of the body. The veins carry oxygen-poor blood back to the heart to start the circulation process over.

Detailed explanation-2: -Blood is pumped through the valves into the ventricles. Where the atria meet the ventricles, there is an area of special cells-called the atrio-ventricular node-which pass the electrical signals throughout your heart muscle by a system of electrical pathways, known as the conducting system.

Detailed explanation-3: -With each heartbeat, the heart sends blood throughout our bodies, carrying oxygen to every cell. After delivering the oxygen, the blood returns to the heart. The heart then sends the blood to the lungs to pick up more oxygen. This cycle repeats over and over again.