A Journey of a Red Blood Cell!

This is my science homework. We had to imagine we were a Red blood cell and write about our journey, so here's mine, Enjoy

Every single second I hear the soft beating noise of a spectacular muscular organ. This is positioned behind the rib cage, between the two large lungs. It’s tiled ever so slightly left; can you guess where I am? I’m only a small red blood cell sitting next to the heart, just about to start my journey around the body.

I start off getting pushed through the main Artery, the Dorsal Aorta. The Dorsal Aorta divides and branches out into many smaller Arteries, which all lead to different sections of the body.

Arteries are very tough on the outside, but smooth on the inner. They have three layers: the outer layer of tissue, a muscular middle, and an inner layer which is made up of epithelial cells. The muscle in the middle is elastic and is very strong. Whereas the inner is smooth this allows me and my friends to flow easily without any obstacles.

The middle wall of the Artery helps to move us along. When the heart beats, it expands which pushes us into the Artery. When the heart relaxes again the walls contacts, it creates a force which sends us flying down the Artery. The Artery goes through the lungs, which there we each collect Oxygen, to pump around the body. We all are now oxygen – rich blood cells, so the Arteries deliver us to the Capillaries. This is a much tighter squeeze; we all have to go through in a single file, moving slowly.

Capillaries are very thin and fragile; they are actually only one epithelial cell thick. This is where the exchange of Oxygen and Carbon Dioxide happens. I release my Oxygen which goes through the wall into the surrounding tissue. That tissue releases its waste products, like Carbon Dioxide, which then goes back through the wall which I then absorb. The Capillaries move us, now waste – rich blood, to the veins which will take us back to the heart.

The vein is similar to the Artery, but they are not as strong. They have the three layers, but are thinner, containing less tissue. We now don’t carry any Oxygen, that’s why when you look at your veins. They are blue, Oxygen gives blood its red colour, and without it the blood is blue. When all then reach the heart once more and this whole process is repeated over and over. It never stops, if it does, well you're dead.