Question

Identify the correct option.
Statement 1: Blood from venacava and pulmonary veins enters the right and left atria respectively.
Statement 2: The aperture between the atria and the ventricles is closed by valves.

• A. Statement 1 is true and statement 2 is false.
• B. Statement 1 is false and statement 2 is true.
• C. Both the statements are true.
• D. Both the statements are false.

Answer 1

The correct option is C Both the statements are true.

One contraction and one relaxation of atria and ventricles is called one cardiac cycle. The cardiac cycle begins with joint diastole in which all the four chambers of the heart are in relaxed state. Blood from venacava and pulmonary veins enters the right and left atria respectively. The aperture between the atria and the ventricles is closed by valves. When the valves are closed forcibly, first sharp sound of the heart (lub) can be heard.