Describe the journey of a Red Blood Cell around the body - Essay Example

A spectrin network attached to the lipid bilayer contains several organic proteins, phospholipids, sphingolipids and cholesterol. This type of attachment increases the stiffness of the RBC. Moreover, this sort of spectrin protein allows the free diffusion of vital component from extracellular fluid to intracellular fluid. (Li & Lykotrafittis, 2012). The journey of red blood cells (erythrocytes) usually begins in the circulatory system. During their passage through the blood vessels the erythrocytes undergo several important changes in shape and structure particularly when needed to pass through the narrow passages in the circulatory system.

An erythrocyte is a biconcave disc of a diameter ranging between 6-8 microns, with mean thickness of 2.5 micrometres at the periphery and approximately 1 micrometre towards the centre of the cell (Guyton & Hall, 2006). Transporting of oxygen from lung to various other organs is the function of the RBCs during their journey in the human circulatory system. Importantly, this oxygen available for the functioning of organs is stored into the haemoglobin of RBC and when it reaches its particular destination, oxygen is liberated from haemoglobin and it moves through the cellular passive diffusion.

Furthermore, carbon dioxide (CO2) that is released after cellular activities is then again fused with haemoglobin of RBC. This deoxygenated blood due to presence of CO2 into the haemoglobin then enters into the heart, and is finally diffused to the lungs. It was reported that in some lower animals (some invertebrates), Hb is present as a free protein in plasma and it is not bound to the RBCs like in human beings. The total life span of each erythrocyte in the circulation is 120 days (Dean, 2005).

But during this period if any of them gets damaged, then they could be eliminated from the circulatory system with the help of macrophages which is usually present in the bone marrow, spleen or in the liver (Premkumar, 2004). A normal man has an average of 5,200,000 red blood cells (RBC) per cubic millimetre and a normal woman has an average of 4,700,000 RBCs per cubic millimetre (Guyton & Hall, 2006). Around 3 million red blood cells (RBC) enter the circulation each second (Starr & McMillan, 2012).

Haemoglobin is usually concentrated in the red blood cells (RBC); the metabolic limit of haemoglobin-forming mechanism of the body allows only a maximum concentration of 34grams of Haemoglobin in each 100 millilitres of cells (Guyton & Hall, 2006). In any normal and healthy individual, the haemoglobin (Hb) concentration remains at this maximum permitted level. 2. Bone marrow, Journey and Production of erythrocytes: Production of the erythrocytes from the bone marrow is called erythropoiesis (Schlossberg & Zuiderna, 1997).

Apart from bone marrow, red blood cells are also produced by various other organs during the early development of human body. Yolk Sac is the primary site of the production of RBCs during the early embryonic period (Guyton & Hall, 2006, p. 421). Liver serves as the main organ for RBC production during the middle trimester of gestation while lymph nodes and spleen also produce an amount of RBCs during this stage of development (Guyton & Hall, 2006, p. 421). Bone marrow is an important part of human body for the production of red blood cells (RBC) during the last month of gestation and soon after the birth (Guyton & Hall, 2