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Right Atrium
The right atrium is the upper chamber on the right side of the heart. Besides being the first cardiac structure to recieve blood returning from the body, it is also the home of the structure that controls how fast the heart beats. This structure is called the sinus node. The sinus node normally sends out electrical signals at a rate of 60 - 100 times per minute. When you engage in strenuous activity the heart rate will usually increase and when you rest, your heart will beat at a slower rate.
Some of the other structures found in the right atrium are listed below. Click on any of these terms to see a more detailed definition.
Right Atrial Structures
- Sinus Node: In most peop.e, the sinus node is located at the SVC / RA junction in the right atrium where the posterior lateral wall connects to the superior vena cava. As the primary control for the heart, this structure regulates how fast the heart beats. It does so by recieving input from the vein by way of the Vegus nerve. The information from the brain is regulated by the need for oxygen and nutrients for the cells throughout the body. During times of increased physical activity, the cells of the body require more oxygen. This need is transmitted to the brain which in turn sends signals to the sinus node instructing it to increase the number of times it generates signals that will cause cardiac cells to contract or depolarize.
- Specific Internodal conduction pathways in the atria may exist based on strong physiologic and some anatomical evidence. (Netters)
- Bachman's Bundle acts as the primary conduction pathway between the right and left atrium.
- Atrial Septum
- Foramen Ovale / Fossa Ovalis
- Coronary Sinus
- Eustachion Ridge / Valve
- Tricuspid Valve - Semilunar Valve
- Anterior Cusp
- Septal Cusp
- Posterior Cusp
- Triangle of Koch
- Inferior Vena Cava
- Right Atrial Isthmus
- Crista Terminalis (Terminal Crest and Terminal Sulcus)
- Right Atrial Appendage
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