The key difference between auricle and atrium is that auricle is a small appendage arising from each atrium while atrium is one of the two upper chambers of the heart.
The heart is a muscular pump that maintains blood circulation throughout the body. The heart has four chambers: two atria and two ventricles. Atria are the upper chambers of the heart while ventricles are the lower chambers of the heart. Right and left atria bring blood to the heart. Furthermore, auricles are two small appendages attached to atria. Both atrium and auricle have functional and structural differences. Hence, this article discusses the difference between auricle and atrium.
CONTENTS
1. Overview and Key Difference
2. What is an Auricle
3. What is an Atrium
4. Similarities Between Auricle and Atrium
5. Side by Side Comparison – Auricle vs Atrium in Tabular Form
6. Summary
What is an Auricle?
Auricle is a small appendage that arises from each atrium. It resembles an earlobe. There are two auricles in the heart: left auricle and right auricle. Right auricle forms the rough anterior part of the right atrium, whereas left auricle forms the rough part of the left atrium. Musculi pectinati are parallel ridges found only in these auricles. Auricles are important as they help to increase the blood volume that can be held by atria.
What is Atrium?
An atrium is one of the two upper chambers of the heart. Artrium receives blood into the heart. There are two atria in the heart as right atrium and left atrium. Unlike the walls of ventricles, atria have thin walls. Both atria separate through the inter-atrial septum. The deoxygenated blood collected from the tissues of the entire body enters the right atrium through the superior and inferior vena cavae. Once the blood enters the right atrium, the blood then passes into the right ventricle through the right atrioventricular orifice under the control of the tricuspid valve.
Figure 01: Heart
Right atrium has two important nodes as the sinoatrial (SA) node (the pacemaker of the heart that generates cardiac impulses) and atrioventricular (AV) node, which passes the impulses to the ventricles. Moreover, four pulmonary veins bring oxygenated blood from the lungs into the left atrium. Once the left atrium fills with blood, blood flows into the left ventricle through the left atrioventricular orifice under the control of the mitral valve.
What are the Similarities Between Auricle and Atrium?
- Auricle and atrium are two structural features of the heart.
- There are two auricles and two atria in our heart.
- Moreover, auricles are atrial appendages.
- Auricles increase the capacity of atria and increase the volume of blood atria can hold.
What is the Difference Between Auricle and Atrium?
Auricle is an atrial appendage which resembles an earlobe while atrium is one of the two upper chambers of the heart. This is the key difference between auricle and atrium. Furthermore, auricle increases the capacity of the atrium and increases the volume of the blood that can hold by the atrium. On the other hand, autrium receives blood to the heart. This is another difference between auricle and atrium.
Summary – Auricle vs Atrium
Atrium is an upper chamber of our heart. There are two atria as right atrium and left atrium. Right atrium receives de-oxygenated blood to the heart while left atrium receives oxygenated blood to the heart. Auricle is a small appendage arising from the atrium. Thus, there are two auricles in two atria. Moreover, auricle increases the capacity of atrium, providing a rough interior part to atria. Hence, auricles are important for atria functioning. This summarizes the article difference between auricle and atrium.
Reference:
1. “Atrium (Heart).” Wikipedia, Wikimedia Foundation, 29 May 2019, Available here.
2. “Left Auricle – Anatomy Pictures and Information.” Innerbody, Available here.
Image Courtesy:
1. “Blausen 0451 Heart Anterior” By Blausen Medical Communications, Inc. – Donated via OTRS, see ticket for details (CC BY 3.0) via Commons Wikimedia