_________ blood enters the right atrium; it flows through a valve into the right ________, which pumps it through _______, which
flow into capillaries in the ________ where it gives off CO2 and picks up O2. The oxygenated blood flows into _______ back to the heart where it enters the left ________. The blood flows through a valve into the left _________, which pumps it through _________, which branch into smaller __________ where O2 is delivered to all body cells before returning through ________ to the right ________ of the heart.
Specialized tissue on the wall between the atria. Electrical impulses pass from the pacemaker (SA node) through the _______ and the atrioventricular bundle (bundle of His) toward the ventricles.atrium (pl. atria)One of two upper chambers of the heart.capillary<span>Smallest blood vessel. Materials pass to and from the bloodstream through the thin walls. They have walls that are only one endothelial cell in thickness. This delicate, microscopic vessel carries nutrient-rich, oxygenated blood from the arteries and arterioles to the body cells. There, the nutrients are burned in the presence of oxygen (catabolism) to release energy. At the same time, waste products such as carbon dioxide and water pass out of the cells and into these blood vessels. Waste-filled blood then flows back to the heart in small venues, which combine to form larger vessels called veins.</span>carbon dioxideGas (waste) released by body cells, transported via veins to the heart, and then to the lungs for exhalation.coronary arteriesBlood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle.deoxygenated bloodBlood that is oxygen-poor.diastole<span>Relaxation phase of the heartbeat.</span>
