red blood cell – cells in the blood that transport oxygen throughout the body

To remember the meaning of red blood cell, use the following mnemonic:

The red blood flowed into the cell transporting oxygen tanks.

Red blood cells are the most abundant type of cell in your blood and have a very specific job - to transport oxygen around the body. These cells have a concave disc shape, which means they're round and flat with a dip in the middle on both sides. This unique shape gives them a large surface area compared to their volume, making them incredibly efficient at absorbing and releasing oxygen. Unlike most cells in the body, mature red blood cells don't have a nucleus, which creates more space inside the cell for haemoglobin, the iron-containing protein that actually carries the oxygen molecules.

When you breathe in, oxygen from your lungs diffuses into your bloodstream and binds to the haemoglobin in your red blood cells. These oxygen-rich cells then travel through the circulatory system, delivering oxygen to tissues and organs throughout the body. At the same time, they pick up carbon dioxide, a waste product from respiration, and transport it back to your lungs where it can be exhaled.