What is the pulmonary valve?
The pulmonary valve is one of the four heart valves. It has the shape of a crescent and is located between the right ventricle and the pulmonary artery. The pulmonary 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 pulmonary 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. A fibrous nodule placed on each free margin of the cusps unilaterally close the orifice during ventricular contraction.
Congenital defects of the pulmonary valve may affect cardiac circulation function. Pulmonary valve stenosis is a condition where the outflow of blood of the heart is damaged at the pulmonic valve. This results in the reduction of blood flow to the lungs. The condition is generally caused by congenital heart disease and can be treated by undergoing balloon valvuloplasty, a procedure that widens a heart valve that is narrowed. With the proper medical assistance, further complications can be prevented.
What function does the pulmonary 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 pulmonary valve oversees the transition of deoxygenated blood between the right ventricle and pulmonary artery, by ensuring its function in preventing 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). During ventricular contraction, blood is pushed through the pulmonary artery and the pressure difference closes it again after transition. The flow frequency of the pulmonary valve in normal conditions is equal to 75 cm per second.