Erythrocytes or Red Blood Cells make up 99.9% of the formed elements in plasma. RBC's are red due to the pigment hemoglobin.Hemoglobin contains iron which attracts oxygen molecules and allows the cell to bind with the molecule. Hemoglobin also gives blood its metallic taste and transports oxygen and carbon dioxide to and from cells.
Characteristics
Erythrocytes are anucleate, or they don't contain a nucleus; they lack mitochondria, and obtain their energy through anaerobic means, where they do not use up the oxygen they carry. The RBC's cell shape is biconcave, meaning both side 'cave' in. Their shape allows them to great surface area to carry more oxygen. They are very flexible, and are also amitotic, which means they are unable to replicate. RBC's make up 44.9% of blood, which is also referred to as hemacrit.
Function
RBC's two main functions are:
to carry oxygen to cells,
and to transport carbon dioxide away from the cells.
Did you know?!
Red blood cells can only live up to 120 days!
Humans only have 4-5 liters of blood in their body!
Blood is NEVER blue! Only the casing surrounding the vessels are blue.
The average human has up to 25 trillion RBC's in their body at one time!
You can only donate blood every 56 days!
A red blood cell contains 280 million hemoglobin molecules!