Blood Cells & Formed Elements of the Blood

Author: Scott A. Sheffield MS

Last update:

Introduction to the Formed Elements of the Blood:

The formed elements are cells, cell remnants, and cell fragments in the blood. image descriptionRed Blood Cells (RBCs or erythrocytes) make up more than 95% of the formed elements.

A section of capillary.
A red blood cell in a section of capillary animation slide 2
A red blood cell in a section of capillary animation slide 3
A red blood cell in a section of capillary animation slide 4
A red blood cell in a section of capillary animation slide 5
A red blood cell in a section of capillary animation slide 6
A red blood cell in a section of capillary animation slide 7
A red blood cell in a section of capillary animation slide 8
A red blood cell in a section of capillary.

Because they lack a nucleus and organelles, most RBCs in the bloodstream are not fully functional cells. Instead, they serve as temporary, hemoglobin-filled containers that transport oxygen throughout the body.

Also included in the formed elements are five types of white blood cells (WBCs or leukocytes). They are part of the immune system and that helps protect the body from foreign invaders. The WBCs are identified and classified based on their stained appearance.

Three of the WBCs have cytoplasmic granules and are called granulocytes:

  1. image descriptionNeutrophils
A section of capillary.
A neutrophil in a section of capillary animation slide 1
A neutrophil in a section of capillary animation slide 2
A neutrophil in a section of capillary animation slide 3
A neutrophil in a section of capillary animation slide 4
A neutrophil in a section of capillary animation slide 5
A neutrophil in a section of capillary animation slide 6
A neutrophil in a section of capillary animation slide 7
A neutrophil in a section of capillary animation slide 8
A neutrophil in a section of capillary.
  1. image descriptionEosinophils
A section of capillary.
An eosinophil in a section of capillary animation slide 1
An eosinophil in a section of capillary animation slide 2
An eosinophil in a section of capillary animation slide 3
An eosinophil in a section of capillary animation slide 4
An eosinophil in a section of capillary animation slide 5
An eosinophil in a section of capillary animation slide 6
An eosinophil in a section of capillary animation slide 7
An eosinophils in a section of capillary.
  1. image descriptionBasophils
A section of capillary.
A basophil in a section of capillary animation slide 1
A basophil in a section of capillary animation slide 2
A basophil in a section of capillary animation slide 3
A basophil in a section of capillary animation slide 4
A basophil in a section of capillary animation slide 5
A basophil in a section of capillary animation slide 6
A basophil in a section of capillary animation slide 7
A basophil in a section of capillary.

 

The remaining two types of WBCs do not have cytoplasmic granules and are classified as agranulocytes:

  1. image descriptionLymphocyte
A section of capillary.
A lymphocytes in a section of capillary animation slide 1
A lymphocytes in a section of capillary animation slide 2
A lymphocytes in a section of capillary animation slide 3
A lymphocytes in a section of capillary animation slide 4
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A lymphocytes in a section of capillary animation slide 6
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A lymphocyte in a section of capillary.
  1. image descriptionMonocytes

Learn to identify cells under the microscope with these histology quizzes and labelling exercises.

A section of capillary.
A monocyte in a section in capillary animation slide 1
A monocyte in a section in capillary animation slide 2
A monocyte in a section in capillary animation slide 3
A monocyte in a section in capillary animation slide 4
A monocyte in a section in capillary animation slide 5
A monocyte in a section in capillary animation slide 6
A monocyte in a section in capillary animation slide 7
A monocyte in a section in capillary animation slide 8
A monocyte in a section of capillary.

The smalled formed elements are called image descriptionplatelets (thrombocytes). These are actually cytoplasmic fragments that pinch from large cells called megakaryocytes. Phospholipids released from platelets help initiate the clotting process.

A section of capillary.
Platelets in a section of capillary animation slide 1
Platelets in a section of capillary animation slide 2
Platelets in a section of capillary animation slide 3
Platelets in a section of capillary animation slide 4
Platelets in a section of capillary animation slide 5
Platelets in a section of capillary animation slide 6
Platelets in a section of capillary.
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