Imagine you are a red blood cell sitting in the right atria of the heart. Write a paragraph that describes what happens to this red blood cell as it moves through the body. What structures will it pass through? How will it interact with oxygen?

A red blood cell, sitting in the right atria of the heart is chocolate-brown in color since its a deoxygenated red blood cell with carbon dioxide rather than oxygen in its hemoglobin.

First

The tricuspid valve pumps it through the right ventricle

Secondly

pulmonary valve pumps it from the right ventricle to the pulmonary circulation.

Then

In the alveoli of the lungs, gas exchange occurs during pulmonary circulation

The end product is oxyhemoglobin (bright red colour) I. e oxygenated blood

The next step

pulmonary veins is the means whereby the red blood cell go to the left atria from the pulmonary circulation through the aortic valve

to mitral valve then to the aorta and systemic circulation

Therefore

oxygen is replaced by carbon dioxide during systemic circulation indicating a end to cellular respiration

Lastly

It's transported back to the right atrium of the heart completing the cardiac cycle.