The heart is one of the most vital organs in the human body, as it plays a crucial role in supporting life and pumping blood throughout the circulatory system. The heart, the powerhouse of the circulatory system, ensures life by pumping blood throughout the body. This blog delves into its anatomy, functions, and the process of blood circulation.
Understanding the Anatomy of the Heart
Getting an overview of the heart's anatomy is practical before entering its functions and blood circulation. The human heart is a muscular organ of about fist size, located in the chest cavity slightly leftwards of the body's midline. The heart pumps blood to all body parts to maintain homeostasis and support cellular functions. The human heart diagram has been categorized into several key elements, which are discussed below:1. Chambers of the Heart
The heart is composed of four chambers:- Left Atrium: This is the upper left chamber receiving oxygenated blood from the lungs through pulmonary veins.
- Right Atrium: The upper right chamber receives deoxygenated blood from the body through the superior and inferior vena cavae.
- Left Ventricle: The lower left chamber pumps oxygenated blood to the body through the aorta.
- Right Ventricle: The right ventricle, located at the lower right side pumps deoxygenated blood to the lungs using the pulmonary artery.
2. Heart Valves
The heart contains four significant valves that maintain blood flow between the chambers:- Mitral Valve: Between the left atrium and the left ventricle.
- Tricuspid Valve: Between the right atrium and the right ventricle.
- Pulmonary Valve: Smaller valve positioned between the right ventricle and the pulmonary artery.
- Aortic Valve: Between the left ventricle and the aorta.
3. Blood Vessels of the Heart
The heart is attached to some other important blood vessels which carry blood through the body in all directions:- Aorta: The largest artery carries oxygenated blood from the left ventricle to the body.
- Pulmonary Artery: Carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
- Pulmonary Veins: Carry oxygen-rich blood from the lungs to the left atrium.
- Vena Cavae: Superior and inferior vena cavae return deoxygenated blood from the body to the right atrium.
4. Coronary Arteries
The heart must constantly be supplied with oxygen-rich blood to function at its best. The coronary arteries branch off the aorta to supply blood to the heart muscle, or myocardium. These arteries ensure that the heart has enough oxygen to pump effectively.Location of the Heart
The heart is situated on the left side of the breast's center, behind the breastbone, and in a region between the lungs termed the mediastinum. To illustrate this clearly, please refer to the diagram of the human heart where the heart itself is shown. It slopes more to the left side. Thus, the lower end of the heart, referred to as the apex, points leftward within the human body.Function of the Heart
The heart's primary function is to pump blood, which supplies oxygen, nutrients, and waste products within the body. The process is called blood circulation. In this process, two circuits comprise the overall process: pulmonary and systemic.1. Pulmonary Circulation
Deoxygenated blood flows back to the right atrium from the body via the superior and inferior vena cavae. From there, it passes through the tricuspid valve into the right ventricle. The right ventricle contracts and pumps blood through the pulmonary valve to the pulmonary artery that carries it to the lungs, where carbon dioxide is exchanged with oxygen and blood is oxygenated. Oxygen-carrying blood returns to the heart via the pulmonary veins and enters the left atrium.2. Systemic Circulation
From the left atrium, it passes through the mitral valve to the left ventricle. The left ventricle walls are the thickest to develop high force and pump the oxygenated blood through the aortic valve into the aorta. From the aorta, blood is carried to smaller arteries, arterioles, and finally, capillaries at the cellular levels where nutrient and gas exchange happens. Once it has delivered oxygen and nutrients to the tissues, blood returns to the heart via veins, which empty into the right atrium to complete the circuit.Blood Supply of the Heart
Like all other tissues, the heart needs an oxygen-rich blood supply to function correctly. The coronary arteries are the first branching off the aorta, supplying this oxygen-rich blood to the heart. These branching arteries further split into smaller vessels to form a network through which blood flows into the heart. The coronary arteries are crucial for the heart's health; any blockage in these arteries, as occurs in coronary artery disease, can result in severe heart diseases, such as a heart attack. The coronary arteries have two major types.- Left Coronary Artery (LCA): The LCA splits to the left anterior descending artery and the left circumflex artery; meanwhile, the anterior descending artery supplies the front of the heart, and the left circumflex artery supplies the side and back.
- Right Coronary Artery (RCA): RCA supplies the heart's right side and the left ventricle's bottom.
How Circulation of Blood Works in the Heart
Blood circulation inside the heart is synchronized; if everything works, the heart pumps blood into the lungs and other parts of the body smoothly. A blood flow cycle into and out of the heart can then be broken into the following stages.- Deoxygenated Blood Enters the Right Atrium: After delivering oxygen to the body and thus losing oxygen, blood returns to the heart into the right atrium through the superior and inferior vena cavae.
- Blood Flows into the Right Ventricle: The walls of the right atrium now contract, and this pumps blood through the tricuspid valve into the right ventricle.
- Blood is Published to Lungs: After contraction, blood is pumped by the right ventricle into the pulmonary artery via the pulmonary valve. It will be transported through the pulmonary arteries to the lungs for oxygenation.
- Oxygenated Blood Returns to the Heart: Once the blood has oxygenated in the lungs, it is returned to the heart through pulmonary veins to the left atrium.
- Oxygenated Blood Flows into the Left Ventricle: The contraction of the left atrium opens the mitral valve, allowing blood to flow into the left ventricle.
- Blood is Pumped to the Body: The left ventricle contracts, pumping oxygen-rich blood through the aortic valve into the aorta, which distributes it to the rest of the body.
