Facts about Red Blood Cells
- 08
Osmotic pressure causes red blood cells to shrivel in hypertonic saline solutions and swell in hypotonic solutions, a principle demonstrated by the 0.9 percent sodium chloride concentration used in isotonic IV fluids.
- 07
A single red blood cell completes approximately 170,000 circuits through the human circulatory system during its 120-day lifespan, traveling roughly 930 miles total.
- 06
Mature mammalian red blood cells lack nuclei and mitochondria, allowing them to carry 25 percent more oxygen than nucleated cells would permit.
- 05
In humans, each red blood cell contains approximately 270 million hemoglobin molecules, allowing a single cell to transport roughly one billion oxygen molecules throughout the body.
- 04
Hemoglobin molecules within red blood cells contain iron at their core, which binds oxygen molecules and gives blood its characteristic red color when oxygenated.
- 03
The biconcave disc shape of red blood cells maximizes surface area to volume ratio, enabling efficient oxygen absorption and allowing them to squeeze through capillaries just 5 micrometers wide.
- 02
During fetal development, the spleen produces red blood cells until birth, when bone marrow takes over this responsibility completely.
- 01
Approximately 2 million red blood cells are produced every second in bone marrow to replace those that die after circulating for 120 days.