erythrocyte
Meaning of erythrocyte: Stripped of a nucleus and packed with hemoglobin, this cell trades any ability to repair itself for maximum oxygen carrying capacity.
Definition of erythrocyte
An erythrocyte, better known as a red blood cell, is the blood cell that carries oxygen from the lungs to the rest of the body. It has no nucleus and no mitochondria, leaving the interior free for hemoglobin, the iron containing protein that binds oxygen. Its flexible, dished shape lets it fold through vessels narrower than itself.
How erythrocyte is built
- erythr/o Combining form · Greek red
- -cyte Suffix · Greek cell
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
Why does the shape matter?
An erythrocyte is a disc pressed inward on both sides. That form gives more surface for gases to cross relative to the volume inside, and it leaves the cell floppy enough to bend double and squeeze through the smallest vessels, some of which are narrower than the cell at rest. Emptying out the nucleus frees more room for hemoglobin, but it comes at a price. With no nucleus the cell cannot build fresh proteins, and with no mitochondria it cannot repair oxidative damage well. It runs on glucose broken down without oxygen, which has the neat consequence that the cell consumes almost none of the oxygen it is carrying.
Where do they come from, and where do they go?
Production happens in the bone marrow, prompted by erythropoietin, a hormone released by the kidney when it senses too little oxygen reaching it. Building the cells requires iron, vitamin B12 and folate, and a shortage of any one of them shows up in the size or number of the cells produced. Each erythrocyte then circulates for roughly four months. Worn cells are pulled out of the blood by scavenging cells in the spleen and liver, their iron salvaged for reuse and the remainder of the hemoglobin broken down into bilirubin, the pigment that colors bile.
What do the laboratory numbers measure?
| Measurement | What it reports |
|---|---|
| Red cell count | How many cells occupy a given volume of blood |
| Hemoglobin | How much oxygen carrying protein the blood holds |
| Hematocrit | The share of blood volume taken up by the cells |
| Mean cell volume | Average cell size, which points toward the cause of a shortfall |
| Reticulocyte count | How many young cells the marrow is releasing |
Together these separate the two questions that matter in anemia: whether the blood carries enough oxygen, and why it does not. Small pale cells point toward iron shortage or blood loss, large cells toward a vitamin B12 or folate problem, and a low reticulocyte count toward a marrow that is not producing rather than a bloodstream that is losing.
Also known as
Used in a sentence
The complete blood count showed a reduced erythrocyte count consistent with anemia.
Good to know
Erythrocyte count and hemoglobin concentration are related but distinct measurements, since the amount of hemoglobin inside each cell can vary even when the number of circulating cells is normal.
Word origin
Where “erythrocyte” comes from
Formed from Greek erythros, meaning red, and kytos, meaning cell.