How it works
This formed elements of blood diagram is a drawing of a stained smear: red blood cells, platelets and one each of the five white blood cells. A second view cuts a red cell open; see the red blood cell diagram.
Read the full guide
Identifying white blood cells
Look at the nucleus and the granules. A neutrophil has a nucleus of several lobes and fine granules; an eosinophil two lobes and large granules; a basophil granules that hide the nucleus. A lymphocyte is small and nearly all nucleus; a monocyte is the largest, with a kidney-shaped nucleus. As an identifying white blood cells quiz, the tool asks each in turn.
A blood cell diagram labeled two ways
The smear shows the formed elements. The tube shows the plasma they float in, which rises to the top when blood is spun. The cut red blood cell shows its shape: a disc that is thin in the middle.
- Labeled white blood cells are easier to tell apart by the nucleus than by size.
- The white cells are drawn larger against the red cells than they are, so the nuclei can be seen.
Questions and answers
What are the formed elements of blood?
The red blood cells (erythrocytes), the white blood cells (leukocytes) and the platelets, which are cell fragments. They float in the plasma, the liquid part of blood.
What are the five types of white blood cells?
Neutrophils, eosinophils and basophils, which are the granulocytes, and lymphocytes and monocytes, the agranulocytes. Neutrophils are the most common in the blood and basophils the rarest.
What shape is a red blood cell?
A biconcave disc: thick at the rim and thin in the center, like a donut whose hole is not cut through. It has no nucleus and is filled with hemoglobin.
Is this the key to “label the formed elements of the blood”?
That sentence is a publisher’s labeling activity. This page is a drawing of our own, not a micrograph, with the same seven formed elements, so the cells sit in different places.