Chapter 35, Problem 13STP

Summary Introduction

To write:

The difference between the three main vessels that blood flows through as it goes from the heart through the body, and returns to the heart.

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.

Explanation of Solution

The three main blood vessels are the arteries, the capillaries and the veins. Arteries are large blood vessels that carry oxygen-rich blood from the heart. They are able to withstand high blood pressures as they are pumped through the heart. Capillaries are microscopic blood vessels in which important substances and wastes are exchanged. The capillary wall facilitates the exchange of materials between the blood and the cells of the body by diffusion. The veins are the largest blood vessels carrying oxygen-poor blood back to the heart. By the time the blood flows into the veins, the original force of the heart has less effect on the movement of the blood.

Conclusion

Thus, the blood vessels carry blood to the whole body from the heart and return to the heart. Breathing movements exert a squeezing pressure against veins in the chest forcing blood back to the heart.