Chapter 30, Problem 1MCQ

What is the advantage of a four-chambered heart?

1. a. It uses the least energy of any type of heart.
2. b. It maximizes the amount of O₂ reaching tissues.
3. c. It enhances the mixing of blood from the pulmonary and systemic circulation.
4. d. Both a and c are correct.

Summary Introduction

Introduction:

Human heart is a muscular organ which is responsible for transportation of oxygen and nutrients through blood. It pumps blood through blood vessels. It is also involve in the removal of carbon dioxide and other metabolic waste out of the body. It is located between the lungs and in the middle of chest.

Answer to Problem 1MCQ

Correct answer:

The presence of four chambered heart helps in the transportation of oxygen in tissues. Therefore option (b) is correct.

Explanation of Solution

Reason for the correct statement

The four chambered heart has two chambers which receive deoxygenated blood from whole body and pump that blood to lungs for purification while the other two chambers are responsible for the receiving oxygenated blood from lungs and pumped it into whole bodies through blood vessels. With the help of four chamber heart the deoxygenated blood is easily collected from body and fulfills the oxygen demand of body.

Option (b) is given as “It maximizes the amount of ${\text{O}}_{\text{2}}$ reaching tissues”.

As, “the four chambered heart detoxify and deoxygenated blood and fulfill the oxygen demand of body”, is the right answer.

Hence, option (b) is correct.

Reasons for the incorrect statements:

Option (a), is given as “It uses the least energy of any type of heart”.

The contraction of heart is guided by the actin and myosin filament that are sliding over each other. It is carried out by sliding movement and it generates ATP for the movement of cardiac muscle. Hence, it is a wrong answer.

Option (c), is given as “It enhances the mixing of blood from pulmonary and systemic circulation”.

The four chambered heart helps in prevention of mixing of deoxygenated and oxygenated blood as the deoxygenated blood is carried out by vena cava and pumps it to lungs for purification. Hence, it is a wrong answer.

Option (d), is given as “Both a and c are correct”

The four chambered heart carries deoxygenated and oxygenated blood and it pumps the deoxygenated blood into lungs for purification and after purification it collects oxygenated blood from lungs and pumped it to other parts of body. Hence, it is a wrong answer.

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

Conclusion

The heart has four chambers, two chambers carry deoxygenated blood from body and transfer it to lungs and receives oxygenated blood from lungs and transfer to the whole body.