Anatomia do Coração

Heart Anatomy

The human heart is a muscular organ that pumps blood throughout the body, providing oxygen and nutrients to cells while removing waste products. It is located slightly left of center in the thoracic cavity and rests between the two lungs. The heart has four main parts: the upper right atrium, lower right ventricle, upper left atrium, and lower left ventricle. The walls of the heart are composed primarily of cardiac muscle tissue, which contracts rhythmically to pump blood.

Blood Flow Through the Heart

Blood enters the right side of the heart from the superior and inferior vena cava. This blood has already been deoxygenated and is blue due to the presence of hemoglobin. Once it enters the right atrium, it passes through the tricuspid valve into the right ventricle. As the ventricle contracts and empties, the now oxygen-poor blood is forced out of the pulmonary semilunar valve into the lungs via the pulmonary artery. Here, the carbon dioxide is removed by alveoli, and freshly oxygenated blood is returned to the left side of the heart via the pulmonary veins.

On the left side of the heart, the oxygenated blood enters the left atrium through the pulmonary veins. After passing through the bicuspid valve (also known as the mitral valve), it enters the left ventricle. When the left ventricle contracts, the blood is pushed out of the aortic semilunar valve and into the aorta (the largest artery in the human body). From there, the oxygenated blood circulates throughout the body via smaller arteries.

Structure of the Heart

Chambers

The heart consists of four chambers: the right atrium, right ventricle, left atrium, and left ventricle. Both the right atrium and left atrium are similar in structure and function; they are thin-walled, muscular chambers that serve as a reservoir for blood. The right ventricle and left ventricle are thicker-walled chambers that perform the laborious work of pumping blood.

Heart Valves

Heart valves prevent backflow of blood within the heart during contraction and relaxation cycles. There are four primary valves in the heart:

1. Tricuspid Valve - Located between the right atrium and right ventricle, this valve ensures blood flows only in one direction.
2. Pulmonary Semilunar Valve - Located between the right ventricle and pulmonary artery, this valve prevents blood from flowing backward into the right ventricle when its pressure drops.
3. Mitral Valve - Also known as the bicuspid valve, this valve is situated between the left atrium and left ventricle and controls blood flow between these two chambers.
4. Aortic Semilunar Valve - Positioned between the left ventricle and aorta, this valve regulates the forward flow of oxygen-rich blood from the heart to the body.

These valves maintain the unidirectional flow of blood through the heart by opening and closing according to the pressure differences created by the contracting chambers.

Sistema Cardionector

The systéma cardiológio, or cardiovascular system, includes both the circulatory system and the heart. It is responsible for maintaining homeostasis within the body by transporting gases, nutrients, waste products, and other chemicals to and from various tissues and organs. The heart plays a crucial role in this process by pumping blood, ensuring all organs receive adequate oxygen and nutrients.