Chapter 19, Problem 1DYB

Which of the following is the correct circulatory sequence for blood to pass through part of the heart?

1. a. right atrium → left AV valve → right ventricle → pulmonary semilunar valve
2. b. right atrium → right AV valve → right ventricle → pulmonary semilunar valve
3. c. left atrium → right AV valve → left ventricle → aortic semilunar valve
4. d. left atrium → left AV valve → left ventricle → pulmonary semilunar valve

Summary Introduction

Introduction:

Homeostasis is maintained by continuous circulation of the blood in the body. Heart and blood vessels combine to make the cardiovascular system, where the circulation of blood takes place. The heart and blood vessels are organized into two types of circuits: the pulmonary circulation and systematic circulation.

Answer to Problem 1DYB

Correct answer:

The correct circulatory sequence for blood to pass through part of the heart is right atrium $\to$ right AV valve $\to$ right ventricle $\to$ pulmonary $\to$ semilunar valve.

Therefore, option (b) is correct.

Explanation of Solution

Reason for the correct statement:

Option (b) is given as “right atrium $\to$ right AV valve $\to$ right ventricle $\to$ pulmonary semilunar valve”. The blood vessels are organized into two types of circuits: the pulmonary circulation and systematic circulation. Blood travels throughout the body by circulatory routes. It flows from all the four chambers of the heart, and the  order is: right atrium $\to$ right AV valve $\to$ right ventricle $\to$ pulmonary semilunar valve. The systematic circulation returnsback deoxygenated blood to the right atrium.

Hence, option (b) is correct.

Reasons for incorrect statements:

Option (a) is given as “right atrium $\to$ left AV valve $\to$ right ventricle $\to$ pulmonary semilunar valve”.

The blood of the right atrium is present on the right side of the heart, thus, it travels from the right, but not the left, AV valve. Hence, it is not correct.

Option (c) is given as “left atrium $\to$ right AV valve $\to$ left ventricle $\to$ aortic semilunar valve”.

The blood from the left atrium is present on the left part of the heart, thus, it moves from the left, but not the right, AV valve. Hence, it is not correct.

Option (d) is given as “left atrium $\to$ left AV valve $\to$ left ventricle $\to$ pulmonary semilunar valve”.

The blood from the left ventricles travels form the aortic, but not pulmonary, semilumnar valve. Hence, it is not correct.

Hence, options (a), (c), and (d), are incorrect.

Conclusion

Blood flows from the right side of the heart to the lungs to systematic cells of body and then back to the right side.