Bundle of His .
strong then the right atrium but not as strong as the left ventricle because the left atrium deals with a higher pressure in comparison to the right atrium. The walls of the posterior left atrium are smooth, this part receives the 4 pulmonary veins The wall of the anterior left atrium contain musculi pectinati, small ridges in the wall Unlike in the right atrium there is no definitive division between the two
The ridges in the anterior wall of the right atrium are called pectinate muscles or pectinate ridges. These muscular ridges are important for increasing the surface area of the atrium to allow for more efficient contraction and blood flow.
sinoartial
It is located in the wall of the right atrium near the tricuspid valve.
Pectinate muscles
The ventricles has the strongest wall .
Also spelled sinuatrial valve. It is the valve at the opening of the embryonic sinus venosus into the primordial right atrium. The sinus venosus later develops into part of the right atrium wall, the SA node and the coronary sinus.
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The sinoatrial (SA) node, also known as the pacemaker of the heart, is located in the posterior wall of the right atrium near the entrance of the superior vena cava. It is responsible for initiating the electrical impulses that regulate the heart's rhythm.
The chordate classes that have 3-chambered hearts are Amphibia (the amphibians) and Reptilia (the reptiles). Humans and other mammals (birds too) have a four-chambered heart (left atrium, right atrium, left ventricle, right ventricle). Reptiles and amphibians have a left atrium, a right atrium, but only one ventricle (although the ventricle of reptiles has a small internal wall that divides it to some extent).
The coronary sinus opens into the right atrium, between the inferior vena cava and the superior vena cava.It returns the blood from the substance of the heart, and is protected by a ... Its wall is partly muscular, and at its junction with the great coronary vein is ... groove between the left atrium and ventricle on the posterior surface of the heart. ...