Chapter 34, Problem 8A

Summary Introduction

Introduction:

The circulatory system, additionally known as the cardiovascular system is an important organ system that provides essential substances to all cells for basic activities to occur. Also generally referred to as the cardiovascular system, is a connection composed of the heart as a centralized pump, blood vessels that distribute blood throughout the body, and the blood itself, for transportation of various materials. The circulatory system is classified into two separate loops, they are the shorter pulmonary circuit that exchanges blood between the heart and the lungs for oxygenation; and the longer systemic circuit that transports the blood throughout all other systems and tissues of the body. Both of these circuits start and end up in the heart.

Answer to Problem 8A

Correct answer :

The correct answer is option C. veins.

Explanation of Solution

Explanation/justification for the correct answer :

Option C. veins. Veins contain one −way valves that ensure blood flows in only one direction. Valves additionally assist or help blood transfer back to the heart against the pressure of gravity. So, the correct answer is option C.

Explanation for incorrect answer :

Option A. arteries. Arteries do not need valves because the force from the heart is so high that blood is only able to flow or move in one direction. So, this is an incorrect answer.

Option B. capillaries. The capillaries join the two types of blood vessels and molecules are altered between the blood and the cells across their walls. Veins consist of valves that stop the backflow of blood. So, this is an incorrect answer.

Option D. white blood cells. The major function of white blood cells, or leukocytes is to fight infection. So, this is an incorrect answer.