Introduction
The field of science is surrounded by numerous myths based on different arguments and assumptions. However, such myths are not supported by any verifiable data. One of the myths is that human beings produce 1.7 billion new red blood cells (RBCs) or erythrocytes each day. This presentation addresses where RBCs are made and broken within the human body and their functions.
Where RBCs are Made and Broken Down
RBCs are produced through a process known as erythropoiesis, which occurs in the bone marrow (Trakarnsanga et al., 2017). When the kidneys detect a decrease in the level of oxygen under circulation through the blood, they produce a hormone known as erythropoietin, which in turn activates the differentiation of various precursor cells for RBCs. Erythropoiesis takes place in eight distinct stages to allow the differentiation and maturity of the RBCs. The first seven steps occur in the bone marrow (Bryk & Wiśniewski 2017). However, the last phase takes place in the bloodstream within a maximum of 2 days, where cells mature. After conception, the production of RBCs occurs within the mesoblastic cells that are found in the umbilical vesicle.
After the first four months of fetus formation, erythropoiesis starts taking place in the liver. By the seventh month, the process moves to the bone marrow. After birth, the production of RBCs takes place in the bone marrow of all the bones, and this pattern continues until when one is five years old. At this stage, the production of RBCs in the femur and tibia starts to slow, and it ceases by the time one turns 25 years old (Dzierzak & Philipsen 2013). In adulthood, erythropoiesis takes place in cranial, pelvis, sternum, vertebrae, and rib bones. The rate at which RBCs are produced depends on different factors. For instance, when one is undergoing intensive activities like exercising, erythrocytes are produced in large amounts, as the need for oxygen within the body increases tremendously.
The destruction of RBCs occurs in the spleen. The lifespan of erythrocytes is short as they live for only 120 days (Dzierzak & Philipsen 2013). As the cells grow old, the cell membranes become fragile. Therefore, the cell ruptures as it goes through different tight spots in the process of circulation (De Back et al., 2014). In the spleen, RBCs self-destruct by squeezing through the red pulp of this organ. Some components of the erythrocytes are used in the formation of new cells. For instance, the hemoglobin released from the RBCs is phagocytized by the liver and spleen macrophages (De Back et al. 2014). The iron component is then released back into the blood, where it is transported to bone marrow for the production of more erythrocytes. Alternatively, the iron is stored in the liver in the form of ferritin (Kim & Nemeth 2015). The other components of the destroyed RBCs are broken down into a series of stages until they are converted into bilirubin, which is ultimately converted into bile.
Functions of RBCs
The main function of RBCs is to transport oxygen throughout the body via the blood. Erythrocytes pick oxygen as they pass through the lungs and distribute it to the other body parts (Kuhn et al., 2017). Additionally, as they supply oxygen, they carry carbon dioxide from different body parts back to the lungs for purification.
Conclusion
In adult human beings, RBCs are formed in the bone marrow and destroyed in the spleen. These cells are broken down into different components, which are used in the making of new cells or other products like bile. The main function of erythrocytes is to carry oxygen to different body parts through the blood.
Reference List
Bryk, AH & Wiśniewski, JR 2017, ‘Quantitative analysis of human red blood cell proteome’, Journal of Proteome Research, vol. 16, no. 8, pp. 2752-2761.
De Back, DZ, Kostova, EB, van Kraaij, M, van den Berg, TK & van Bruggen, R 2014, ‘Of macrophages and red blood cells; a complex love story’, Frontiers in Physiology, vol.5, no. 9, pp. 1-11. Web.
Dzierzak, E & Philipsen, S 2013, ‘Erythropoiesis: development and differentiation’, Cold Spring Harbor Perspectives in Medicine, vol. 3, no. 4, pp. 1-16. Web.
Kim, A & Nemeth, E 2015, ‘New insights into iron regulation and erythropoiesis’, Current Opinion in Hematology, vol. 22, no. 3, pp. 199-205.
Kuhn, V, Diederich, L, Keller, TCS, Kramer, CM, Lückstädt, W, Panknin, C, Suvorava, T, Isakson, B, Kelm, M & Cortese-Krott, MM 2017, ‘Red blood cell function and dysfunction: redox regulation, nitric oxide metabolism, anemia’, Antioxidants & Redox Signaling, vol. 26, no. 13, pp.718–742. Web.
Trakarnsanga, K, Griffiths, RE, Wilson, MC, Blair, A, Satchwell, TJ, Meinders, M, Cogan, N, Kupzig, S, Kurita, R, Nakamura, Y, Toye, AM, Anstee, DJ & Frayne, J 2017, ‘An immortalized adult human erythroid line facilitates sustainable and scalable generation of functional red cells’, Nature Communications, vol. 8, no.14750, pp. 1-7. Web.