What is the Difference Between Papillary and Pectinate Muscles?

Papillary and pectinate muscles are two different types of muscles found in the heart of humans, playing crucial roles in the heart's circulation function. The main differences between them are:

• Location: Papillary muscles are located in the ventricles of the heart, while pectinate muscles are found in the atria. Specifically, papillary muscles can be found in both the right and left ventricles, and pectinate muscles can be found in both the right and left atriums.
• Function: Papillary muscles are involved in the contraction of the ventricles, helping to pump blood out of the heart. Pectinate muscles, on the other hand, are involved in the stretching of the atria, which helps to increase the power of contraction without increasing heart mass substantially.
• Structure: Pectinate muscles are parallel muscular ridges in the walls of the atria, resembling the teeth of a comb (pecten). Trabeculae carneae, which are found on the inner walls of both ventricles, are different from pectinate muscles.

In summary, papillary muscles are found in the ventricles and play a role in contracting the heart, while pectinate muscles are found in the atria and help increase the power of contraction without increasing heart mass.

Comparative Table: Papillary vs Pectinate Muscles

Here is a table summarizing the differences between papillary and pectinate muscles:

Both papillary and pectinate muscles are important for the proper functioning of the heart, but they have distinct roles and structures. Papillary muscles are found in the ventricles and help maintain the position of the atrioventricular valves, while pectinate muscles are found in the atria and contribute to the stretching and improvement of the atrial volume.