Red blood cells are the most plentiful component in the blood, making up one of its four primary constituents. These specialized cells, also known as erythrocytes, play a vital role in the functioning of the human body. One of their most crucial functions is the transportation of oxygen and carbon dioxide throughout the body. This is made possible by the presence of significant molecules within the red blood cells.
Red blood cells undergo a developmental process in the bone marrow, starting as immature cells and eventually entering the bloodstream as mature cells. Their remarkable flexibility enables them to adapt their shape according to the size of blood vessels they traverse, facilitating seamless circulation.
Shape and Size
Red blood cells have a unique biconcave shape, resembling a shallow bowl with plump, torus-like edges. This shape provides them with a larger surface area, which is advantageous for efficient gas exchange when compared to cells with more spherical shapes. Additionally, red blood cells are highly flexible and malleable, allowing them to adapt to different environments. In terms of size, a typical human red blood cell has a diameter ranging from 6.2 to 8.2 micrometers. The thickest part of a red blood cell measures just over two micrometers, while the thinnest part can be less than a single micrometer in thickness. To put this into perspective, the width of a single human hair is approximately 60 to 120 micrometers.
Cell Volume
The volume of cells in the human body varies depending on various factors. In adults, the number of red blood cells ranges from 20 trillion to 30 trillion. It is worth noting that men generally have higher red blood cell counts compared to women. Additionally, living at high altitudes can also increase red blood cell counts in both sexes. On average, men have approximately five million cells per microliter of blood, while women have around four million. In contrast, the number of white blood cells is less than 11 thousand, and platelets are around 400 thousand per microliter. Red blood cells make up about 45 percent of the total cells in the blood.