The Heart (The Muscular Pump) Presented By: Adrienne Moore
The Heart Definition: A muscular pump made up of cardiac muscle fibers. Pumping normally includes 60-100 (BPM). Function: Pumps blood throughout the entire body transporting nutrients, oxygen, and eliminating wastes. Location: Located in the mediastinum more so on the left side of the mediastinum in the chest cavity. Size/Shape: Approximately the size of a fist. The shape compared to an upside-down pear. The tip of the heart at the lower edge is called the apex.
The Layers of The Heart The wall of the heart consist of three layers: Endocardium Myocardium Epicardium Pericardium Visceral Pericardium Parietal Pericardium
The Three Heart Layers The Endocardium is the inner layer of the heart lining the heart chambers. It Is a very smooth, thin layer that serves to reduce friction as the blood passes through the heart chambers. The Myocardium is the thick muscular middle layer of the heart. When this muscle layer contracts blood is pump through to the blood vessels. The Epicardium is the outer layer of the heart. The Pericardium is the double-layered pleural sac, t he heart is enclosed in. Another name for the epicardium is the Visceral Pericardium, being the inner layer of the sac. The Parietal Pericardium is the outer layer of the sac. The fluid between the two layer is vital because it reduces friction as the heart beat.
Chambers of The Heart Four Chambers/Cavities The heart is divided into four chamber, these chambers are divided into right and left sides. Upper Chambers:
The Upper Chambers/ Two Atria- Are the receiving chambers of the heart. The blood that is returning to the heart through the veins first collects in the two upper chambers.
The Lower Chambers/ Two Ventricles- Are the more thicker working/pumping chambers. Blood is ejected out of the heart into great arteries, as these ventricles contracts.
Heart Valves(The Door-Keepers) Function: Controls the direction of blood flow by allowing blood to flow only in the forward direction by blocking it from returning to the previous chambers. Four Valves Tricuspid Valve- An atrioventricular valve, which contols the opening between the right atrium and the right ventricle. Pulmonary Valve- A semilunar valve, in appearance looks like a half moon, located between the right ventricle and the pulmonary valve. It prevents blood from returning to the right ventricle as it relaxes. Mitral Valve- A bicuspid valve, where blood flows through this atrioventricular valve to the left ventricle and can’t go back into the left atrium. Aortic Valve- Another semilunar valve located between the left ventricle and aorta. This valve prevents blood from returning to the left ventricle, that has left the left ventricle thorough this valve,
Heart’s Blood Flow The flow of blood starts at the heart moving to the lungs, back to the heart , and then out to the body tissues and parts. The flow of blood is always done in this order: Deoxygenated blood enters the relaxed right atrium via the superior and inferior vena cava. The right atrium contracts and blood is pumped through the tricuspid valve into the relaxed right ventricle. The right ventricle contracts and blood is pumped through the pulmonary valve into the pulmonary artery, carrying it to the lungs for oxygenation. The left atrium then receives blood returning to the heart after the oxygenation process. This blood goes into the relaxed left atrium from the four pulmonary veins. The left atrium contracts and blood flows through the mitral valve into the relaxed left ventricle. Lastly the left ventricle contracts causing blood to pump through the aortic valve and into the aorta, which carries the blood to all areas of the body.