<s>[INST] What Are Heart Valves? [/INST] Heart valves allow for proper blood flow within the heart and the arteries throughout the body. The four heart valves each work as one-way valves to move blood while preventing backflow of blood into one of the heart's four chambers. When the heart beats (contracts), the valves open and close in alternating fashion to pump blood through the two atria upper chambers and two ventricles, the lower chambers. The four types of heart valves are:

Tricuspid valve: Between the right atrium and right ventricle
Pulmonary valve: Between the right ventricle and pulmonary artery
Mitral valve: Between the left atrium and left ventricle
Aortic valve: Between the left ventricle and aorta Source: BRIGHAM AND WOMENS. Link: https://www.brighamandwomens.org/heart-and-vascular-center/diseases-and-conditions/heart-valve-disease. Field: Cardiovascular. Disease: Heart Valve Disease </s>