Heart

The heart serves vital functions in the body, including pumping blood to all organs and tissues. It ensures circulation by receiving oxygenated blood from the lungs and sending it to the rest of the body, while simultaneously receiving deoxygenated blood and sending it back to the lungs for oxygenation.

By maintaining blood pressure, the heart ensures efficient blood flow. It also facilitates the oxygenation of blood by delivering deoxygenated blood to the lungs and receiving oxygenated blood back. The heart adjusts its pumping rate and force to meet the body's demands, and its actions support the delivery of oxygen, nutrients, and hormones while removing waste products.

The heart is primarily composed of cardiac muscle tissue and consists of several essential components. These include: 

• Chambers: The heart has four chambers: two atria (left and right) and two ventricles (left and right). The atria receive blood returning to the heart, while the ventricles pump blood out of the heart. 

• Veins: Tubes known as blood vessels, which receive deoxygenated blood from all the tissues of the body and carry it back to the heart.

• Atrium: Chambers that receive blood from the veins. There are two auricles. The right atrium receives blood from the veins, while the left atrium receives blood from the pulmonary vein that comes from the lungs with oxygen-filled blood. 

• Mitral valve: The valve that regulates the flow of blood from the right atrium to the left ventricle.  

• Tricuspid valve: Responsible for regulating the flow of blood from the left atrium to the left ventricle. 

• Ventricle: Responsible for pumping blood out of the heart. There are two ventricles: the left ventricle pumps oxygenated blood to the body, while the right ventricle pumps deoxygenated blood to the lungs. 

• Aorta: It is a large-calibre artery and the first place through which blood passes when it leaves the heart to the rest of the body. 

• Coronary arteries: Blood vessels that are responsible for carrying oxygenated blood to the cells of the heart. 

• Electrical System: The heart has a specialised electrical system that coordinates the contractions of its muscle tissue. This system includes the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, and Purkinje fibres, which regulate the heart's rhythm and ensure proper pumping. 

• Pericardium: The heart is enclosed in a protective sac called the pericardium. It helps maintain the position and integrity of the heart, shielding it from external forces.