Need an easier read? Change your font
Anatomy Insight | Comic Sans | Lexend
Embedded Files
Heart Valves Anatomy
Heart Valves Anatomy
Blood flow is controlled by four valves, which are essential for maintaining one-way blood flow through the heart by opening and closing in response to pressure changes during the cardiac cycle:
Tricuspid valve: between right atrium and right ventricle
Pulmonary valve: between right ventricle and pulmonary trunk
Mitral (bicuspid) valve: between left atrium and left ventricle
Aortic valve: between left ventricle and aorta
The valve located between the right atrium and right ventricle is the tricuspid valve, also known as the right atrioventricular valve. It typically consists of three leaflets, or cusps, made of endocardium reinforced with connective tissue.
Each leaflet is attached to chordae tendineae, which connect the valve to papillary muscles in the ventricle. Together, these structures control valve movement and prevent backflow of blood into the atrium during ventricular contraction.
At the exit of the right ventricle, where blood enters the pulmonary trunk, is the pulmonary semilunar valve, also called the pulmonary or pulmonic valve. This valve is made up of three small, pocket-like cusps composed of endothelium supported by connective tissue.
When the right ventricle relaxes, blood briefly flows backward from the pulmonary trunk, filling the cusps and forcing the valve to close. This action prevents blood from returning to the ventricle and produces an audible heart sound.
Unlike atrioventricular valves, the pulmonary valve does not have chordae tendineae or papillary muscles.
The valve between the left atrium and left ventricle is the mitral valve, also called the bicuspid valve or the left atrioventricular valve. Clinically, it is most often referred to as the mitral valve.
It has two cusps, unlike the three cusps of the tricuspid valve.
The cusps of the mitral valve are attached by chordae tendineae to two papillary muscles that extend from the ventricular wall, helping stabilize the valve during contraction.
“Commissures of Semilunar Leaflets of Pulmonary Valve” (from File: Commissures of semilunar leaflets of pulmonary valve.png), by xranatomy.com, via Wikimedia Commons, powered by XRANATOMY.COM, from illustrations captured using the 3D Heart Anatomy app, April 8, 2024. Licensed under CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/).
Changes made: Background removed; image cropped; warmth and tint adjusted; sharpened; original labels removed; new labels added. This adapted image is distributed under the same license.
At the base of the aorta is the aortic semilunar valve, or aortic valve, which prevents blood from flowing back into the left ventricle. This valve normally has three cusps. When the left ventricle relaxes, blood attempting to flow backward from the aorta fills the cusps, causing the valve to close and producing an audible sound.
During ventricular contraction, pressure inside the ventricles increases and blood initially moves toward the atria, where pressure is lower. This causes the tricuspid and mitral valves to close. As the ventricles contract, the papillary muscles also contract, increasing tension on the chordae tendineae. This tension holds the valve cusps in place and prevents them from being pushed back into the atria.
In contrast, the semilunar valves (the aortic and pulmonary valves) do not use chordae tendineae or papillary muscles. Instead, they rely on their pocket-like structure. When the ventricles relax and blood flows back toward the heart, pressure fills the cusps, sealing the valve openings and preventing backflow into the ventricles.
Need a recap? Take a look at the Heart Valves notes anatomy notes here.
Need a recap? Take a look at the Heart Valves notes anatomy notes here.
Ready to test what you've learned?
Play through the games below to test your understanding and sharpen your skills.
References
References
Gray, H. (1918). Anatomy of the human body (W. H. Lewis, Ed.; 20th ed.). Lea & Febiger.
J Gordon Betts, Desaix, P., Johnson, E., Johnson, J. E., Korol, O., Kruse, D., Poe, B., Wise, J., Womble, M. D., & Young, K. A. (2013). Anatomy & physiology. Openstax College, Rice University. https://openstax.org/details/books/anatomy-and-physiology
Based on OpenStax, Anatomy and Physiology (2013), licensed under CC BY 4.0.
Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction.
Content paraphrased; adaptations were made.
Google Sites
Report abuse