Erythrocyte

About  Erythrocyte:-

Erythrocyte:  Erythrocyte is a cell that contains hemoglobin and can carry oxygen to the body also called a red blood cell (RBC). The reddish colour is due to the hemoglobin. Erythrocytes are biconcave shape, It increase the cell's surface area and facilitates the dispersal of oxygen and CO₂. This form is maintained by a cytoskeleton composed of a number of proteins. Erythrocytes are extremely flexible and change shape when flowing throughout capillaries. young erythrocytes, called reticulocytes, in general account for 1-2 percent of red cells in the blood.

erythrocyte /eryth·ro·cyte/ (ĕ-rith´ro-sīt) red blood cell; corpuscle; one of the formed elements in blood. Normally in humans the mature form is non-nucleated, yellow, biconcave disk, contains hemoglobin and transporting o₂.

Etymology: Gk, erythros + kytos, cell
Mature red blood cell (RBC); a biconcave disk about 7 μm in diameter or (3.5 μm in radius) that contains hemoglobin limited within a lipoid membrane. It is the main cellular element of the circulating blood and transports oxygen as its main role. The number of cells per cubic millimeter of blood is usually maintains between 4.5 and 5.5 million in men and between 4.2 and 4.8 million in women. It differs with age, activity, and ecological circumstances. For example, an increase to a level of 8 million/mm3 can normally happen at more than 10,000 feet beyond sea level.  An erythrocyte normally lives for 110 to 120 days, while it is removed from the bloodstream and broken down by the reticuloendothelial system. New erythrocytes are formed at a rate of  more than 1% a day; hence a constant level is frequently maintained. Acute blood loss, hemolytic anemia, or chronic o₂ deprivation may cause erythrocyte production to add to greatly. Erythrocytes originate in the marrow of the long bones. Maturation proceed from a stem cell (promegaloblast) through the pronormoblast stage to the normoblast, the final stage before the mature adult cell develops.

History
The first person to describe red blood cells was the young Dutch biologist “Jan Swammerdam”, who had used an early microscope in the year 1658 to study the blood of a frog.  “Anton van Leeuwenhoek” provided one more microscopic description in the year 1674, this time providing an additional precise description of red blood cells, even similar to the size of  25,000 times smaller than a fine grained of sand.
In 1901, “Karl Landsteiner” published his discovery of the three main blood groups are A, B, and C (which he later renamed to O). Landsteiner described the regular patterns in which reactions occurred when serum was mixed with red blood cells, therefore identifying compatible and conflicting combinations among these blood groups. A year later “Alfred von Decastello” and “Adriano Sturli”, two colleagues of Landsteiner, identified a fourth blood group called AB.

In 1959, by using of X-ray crystallography, Dr. Max Perutz was discovered to unravel the formation of hemoglobin, the red blood cells protein carries O₂.
The oldest undamaged red blood cell discovered in May 2012 in Ötzi the Iceman, the mummy of a man died around 3255 BC.

Erythrocytes having mainly of hemoglobin, a complex metalloprotein contains heme groups whose iron atoms temporarily bind to oxygen molecules (O₂) in the lungs or gills and release them out of the body. Oxygen can easily spread through red blood cells, cell membrane. Hemoglobin in the erythrocytes also carries a few of the waste produce carbon dioxide back from the tissues; more waste carbon dioxide, though, is transported back to the pulmonary capillaries of the lungs as bicarbonate (HCO3) dissolved in the blood plasma. Myoglobin, a compound related to hemoglobin, acts to stores oxygen in muscle cells.
The color of erythrocytes is due to the heme group of hemoglobin. The blood plasma only is “straw-colored”, but the red blood cells change color depending on the state of the hemoglobin. Once combined with oxygen the resulting oxyhemoglobin is scarlet, and when oxygen has been out from deoxyhemoglobin is of a dark red burgundy color, appearing bluish through vessel wall and skin. Pulse oximetry takes advantage of this color change to straight compute the arterial blood oxygen saturation using colorimetric techniques. Hemoglobin has high affinity for carbon monoxide, forming carboxyhaemoglobin which is a very bright red in color.
The sequestration of oxygen-carrying proteins inside specialized cells was a vital step in the progress of vertebrates as it permit for few viscous blood, higher concentrations of oxygen, and better dispersal of oxygen from the blood to the tissues. The size of erythrocytes different widely among vertebrate species; erythrocyte width is on average 25% larger than capillary diameter, and it has been hypothesized that this improves the oxygen transfer from erythrocytes to tissues.

The only known vertebrates without erythrocytes are the crocodile   ice-fishes (family Channichthyidae); they live in very oxygen-rich cold water and moves oxygen freely dissolved in their blood. While they do not use hemoglobin anymore, remnants of hemoglobin genes can be found in their genome.