The Cardiovascular system - left atrium

Question 1

Where does the left atrium receive blood from?

Answer 1

The 4 pulmonary veins

Question 2

Where does the left atrium pump blood?

Answer 2

Through the left atrioventricular orifice into the left ventricle

Question 3

Describe the interior surface of the left atrium

Answer 3

The interior surface of the left atrium can be divided into two parts, each with a distinct embryological origin:

• Inflow portion – receives blood from the pulmonary veins. Its internal surface is smooth, and it is derived from the pulmonary veins themselves.
• Outflow portion – located anteriorly and includes the left auricle. It is lined by pectinate muscles and is derived from the embryonic atrium.