The key difference between papillary and pectinate muscles is that papillary muscles are muscles normally found within the ventricles of the heart, while pectinate muscles are muscles normally found within the atria of the heart.
Papillary and pectinate muscles are two different types of muscles in the heart of humans. Papillary muscles can be found in both the right and left ventricles, while pectinate muscles can be found in both the right and left atriums. These muscles play a very important role in the heart. Any disruptions of these muscles may lead to different heart conditions.
CONTENTS
1. Overview and Key Difference
2. What are Papillary Muscles
3. What are Pectinate Muscles
4. Similarities – Papillary and Pectinate Muscles
5. Papillary vs Pectinate Muscles in Tabular Form
6. Summary – Papillary vs Pectinate Muscles
What are Papillary Muscles?
Papillary muscles are muscles found in the ventricles of the heart. These papillary muscles are attached to the cusps of the atrioventricular valves (mitral and tricuspid valves). Normally, papillary muscles attach to the mitral and tricuspid valves via the chordae tendineae. Papillary muscles contract to prevent inversion of these valves on systole or ventricular contraction. Moreover, papillary muscles constitute 10 % of the total heart muscles.
There are a total of five papillary muscles in the heart. Three papillary muscles are found in the right ventricle, and there are two papillary muscles in the left ventricle. The papillary muscles called anterior, posterior, and septal papillary muscles of the right ventricle are attached to the tricuspid valve via chordae tendineae. Moreover, anterolateral and posteromedial papillary muscles of the left ventricle attach to the mitral valve via chordae tendineae. Furthermore, papillary muscles play many vital roles. These muscles begin to contract shortly before ventricular systole and maintain tension throughout. This tension prevents regurgitation or backward flow of ventricular blood into the atrial cavities. A myocardial infarct can cause papillary muscle rupture. Their dysfunction can be caused by ischemia. Both these lead to mitral regurgitation.
What are Pectinate Muscles?
Pectinate muscles are muscles normally found within the atria of the heart. These muscles can be found in both the right and left atria. The right atrium has thicker and coarse pectinate muscles, while the left atrium has smooth and thinner pectinate muscles. Compared to the right atrium, the left atrium has only a few pectinate muscles. The right atrium has more pectinate muscles in the right atrial appendage. Pectinate muscles have muscle fibers that are arranged in a comb-like fashion. These muscles have less mechanical activity and have no significant contribution to atrial contractility.
Pectinate muscles can stretch and improve the volume of the right atrium. Moreover, pectinate muscle folds can act as right atrium volume reserve during adverse or harmful loading conditions. This helps right atrium dilation without much wall stress. Furthermore, disruption of these muscles leads to atrial tachycardia.
What are the Similarities Between Papillary and Pectinate Muscles?
- Papillary and pectinate muscles are two different types of muscles in the heart of humans.
- Papillary and pectinate muscle types are present in both the right and left compartments of the heart.
- Both these muscle types have specific functions that are very vital for the circulatory function of the heart.
- The disruption of these muscle types leads to different heart conditions.
What is the Difference Between Papillary and Pectinate Muscles?
Papillary muscles are the muscles normally present within the ventricles of the heart, while pectinate muscles are the muscles normally present within the atria of the heart. Thus, this is the key difference between papillary and pectinate muscles. Furthermore, papillary muscles involve in the contracting of ventricles, while pectinate muscles involve in the stretching of the atria.
The below infographic presents the differences between papillary and pectinate muscles in tabular form for side-by-side comparison.
Summary – Papillary vs Pectinate Muscles
Heart muscle is one of the three types of vertebrate muscle tissues. Papillary and pectinate muscles are two different types of muscles in the ventricles and atria of the heart. These muscles play vital roles that help the circulation function of the heart. Papillary muscles are normally found within the ventricles of the heart, while pectinate muscles are normally found within the atria of the heart. So, this summarizes the difference between papillary and pectinate muscles.
Reference:
1. “Papillary Muscles and the Left Ventricle.” Mitral Valve Repair Center.
2. “Pectinate Muscles.” Overview | ScienceDirect Topics
Image Courtesy:
1. “2010 Chordae Tendinae Papillary Muscles” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Diagram of the human heart” By Wapcaplet, Yaddah – Own work (CC BY-SA 3.0) via Commons Wikimedia