Chapter 35, Problem 5STP

Summary Introduction

Introduction:

The heart is a muscular organ that is about as large as our fist and is located in the center of our chest. This hollow organ pumps blood all over the body. At the same time, the heart performs two pumping functions. The heart pumps oxygenated blood into the lungs.

Answer to Problem 5STP

Correct answer:

The correct answer is option (C) 3→4.

Explanation of Solution

Explanation/justification for the correct answer:

Option (C) 3→4. In the given image, 3→4 refers to the right atrium to the right ventricle. Blood flows through two loops. The blood goes from the heart to the lungs and back to the heart. Then the blood is pumped from the heart through the body and back into another loop. When the blood flows from the body to the right atrium, it has a low concentration of oxygen but a high concentration of carbon dioxide. This deoxygenated blood flows from the right atrium to the right ventricle and is pumped into the pulmonary arteries leading to the lungs. So, the correct answer is option (C).

Explanation for incorrect answer:

Option (A) 1→2. In the given image, 1→2 refers to the left atrium to the left ventricle. When the blood flows from the head and the body, it flows into the right atrium and then into the right ventricle. So, this is an incorrect option.

Option (B) 2→1. In the given image, 2→1 refers to the left ventricle to the left atrium. When the blood flows from the body to the right atrium, it has a low concentration of oxygen but a high concentration of carbon dioxide. This deoxygenated blood flows from the right atrium to the right ventricle and is pumped into the pulmonary arteries leading to the lungs. So, this is an incorrect answer.

Option (D) 4→3. In the given image, 4→3 refers to the right ventricle to the right atrium. After returning from the head and the body, the blood flows through the heart immediately to the right atrium and then to the right ventricle. So, this is an incorrect answer.