What is the aortic valve?

The aortic valve is one of the four heart valves. It is said to be semilunar aortic due to its crescent shape and it is located between the left ventricle and the aorta. The aortic valve is designed to ensure that blood does not flow backwards on its way towards the heart as well as ensure the proper exchange of oxygen and carbon dioxide levels within the lungs to the entire body’s advantage. 

The heart is an organ that is divided into several parts, which help perform its main function: to carry oxygen-rich blood to the rest of the body (cells, tissues and organs) in order to feed them, and receive carbon dioxide enriched blood to be sent to the lungs, where the oxygen exchange takes place.

The heart valves are small structures that are responsible for preventing blood from flowing backwards by ensuring they steer in one direction towards the heart.

The aortic valve is composed of three membranes (cusps), which mainly consist of collagen and take the form of a crescent. The valve is placed on a muscular ring, through which it is connected to the wall of the heart.

Aortic valve disease may affect cardiac circulation function. The two most common diseases relating to the aortic valve include aortic stenosis and regurgitation. Aortic stenosis is a condition that occurs when the heart’s aortic valve narrows, decreasing blood flow from the heart into the aorta and onward to the rest of the body. The condition can be present at birth, though it tends to develop later in life. Aortic stenosis can be treated by undergoing aortic valve replacement, a type of open heart surgery that involves replacing a failing aortic valve with an artificial heart valve. Aortic regurgitation, also known as aortic insufficiency, occurs when the aortic valve in the heart starts leaking, causing blood to flow in reverse direction during ventricular diastole, from the aorta into the left ventricle. Seeking medical attention is essential in order to prevent further complications from arising.


What function does the aortic valve serve?

The heart is a pump that is known to carry oxygen-rich blood from the lungs to the cells of tissues and organs, in exchange for carbon dioxide enriched blood that needs to be transformed. The oxygenated blood travels towards organs and tissues in the body through the aorta, the artery that carries nourishment to the whole body and further splits into smaller and smaller branches and capillaries. Carbon dioxide enriched blood returns to the heart through the veins, which transform it to oxygen.

The aortic valve oversees the passageway between the left ventricle and the aorta, by ensuring its function in preventing oxygenated blood from flowing back to the lungs.

The cardiac cycle consists of two phases: a relaxation phase (the diastole) and a contraction phase (the systole). During the first stage (the diastole phase), the valves between the atria and ventricles are open, and the whole heart is relaxed. At this stage, the semilunar valves are closed, preventing blood from entering the vascular beds. During the second stage (the systole phase), the atria and ventricles contract in a coordinated manner: first the atria (atrial systole) and then the ventricles (systole). When blood pressure is greater in the ventricle, the valve is open and allows blood to flow through the aorta. Subsequently, when pressure is greater in the aorta, the valve closes and does not allow blood to return to the heart.