red blood cell

Examples of red blood cell in the following topics:

• Red Blood Cells

  • Red blood cells, or erythrocytes (erythro- = "red"; -cyte = "cell"), specialized cells that circulate through the body delivering oxygen to other cells, are formed from stem cells in the bone marrow.
  • In birds and non-avian reptiles, red blood cells contain a nucleus.
  • Hemoglobin is packed into red blood cells at a rate of about 250 million molecules of hemoglobin per cell.
  • Only mammals have anucleated red blood cells; however, some mammals (camels, for instance) have nucleated red blood cells.
  • The advantage of nucleated red blood cells is that these cells can undergo mitosis.

• RBC Anatomy

  • Human erythrocytes or red blood cells (RBCs) are the primary cellular component of blood.
  • This biconcave shape allows the cells to flow smoothly through the narrowest blood vessels.
  • Gas exchange with tissues occurs in capillaries, tiny blood vessels that are only as wide as one cell.
  • Each human red blood cell contains approximately 270 million of these hemoglobin biomolecules, each carrying four heme groups (individual proteins).
  • Diagram the anatomy of an erythrocyte (red blood cell, or RBC)

• Sickle-Cell Disease

  • Sickle-cell disease is an autosomal recessive genetic blood disorder in which red blood cells assume a rigid sickle shape.
  • The red blood cells break down at a faster rate.
  • This scanning electron micrograph shows red blood cells.
  • Figure A shows normal red blood cells flowing freely in a blood vessel.
  • Figure B shows abnormal, sickled red blood cells blocking blood flow in a blood vessel.

• Complete Blood Count

  • The cells that circulate in the bloodstream are generally divided into three types: white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes).
  • Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body.
  • Reticulocytes develop and mature in the red bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells.
  • Like mature red blood cells, reticulocytes do not have a cell nucleus.
  • When there is an increased production of red blood cells to overcome chronic or severe loss of mature red blood cells, such as in a hemolytic anemia, people often have a markedly high number and percentage of reticulocytes.

• Transfusions of Whole Blood

  • Sedimentation, in which whole blood sits overnight, causing the red blood cells and plasma to settle and slowly separate by the force of normal gravity.
  • Whole blood transfusion has similar risks to those of transfusion of red blood cells.
  • Most of the indications for use are identical to those for red blood cells.
  • Whole blood is sometimes "recreated" from stored red blood cells and fresh frozen plasma for neonatal transfusions.
  • This provides a final product with a very specific hematocrit (percentage of red cells) with type O red cells and type AB plasma to minimize the chance of complications.

• Components of Blood

  • Blood is composed of plasma and three types of cells: red blood cells, white blood cells, and platelets.
  • The cellular components of blood are erythrocytes (red blood cells, or RBCs), leukocytes (white blood cells, or WBCs), and thrombocytes (platelets).
  • RBCs, endothelial vessel cells, and other blood cells are also marked by glycoproteins that define the different blood types.
  • The combined surface area of all red blood cells of the human body would be roughly 2,000 times greater than the body's exterior surface.
  • Leukocytes are usually larger in size (10-14 micrometers in diameter) than red blood cells.

• Blood Groups and Blood Types

  • Red blood cells have surface-expressed proteins that define the self/not-self nature of the cells.
  • Red blood cells have surface-expressed proteins that act as antigens, which are molecules that can illicit an immune system response.
  • Red blood cells belong to different groups on the basis of the type of antigen that they express.
  • Many people also have the rhesus D (Rh) antigen expressed by their red blood cells.
  • Blood type (or blood group) is determined, in part, by the ABO blood group antigens present on red blood cell.

• The Role of Blood in the Body

  • The many roles of blood include delivering nutrients and oxygen to cells, transporting waste from cells, and maintaining homeostasis.
  • The components of blood include plasma (the liquid portion, which contains water, proteins, salts, lipids, and glucose), red blood cells and white blood cells, and cell fragments called platelets .
  • Supplying oxygen to tissues (bound to hemoglobin, which is carried in red cells)
  • The cells and cellular components of human blood are shown.
  • Red blood cells deliver oxygen to the cells and remove carbon dioxide.

• Physical Characteristics and Volume

  • Blood contains plasma and blood cells, some of which have hemoglobin that makes blood red.
  • It is an extracellular matrix in which blood cells are suspended in plasma.
  • Blood contains red blood cells (RBCs), white blood cells (WBCs), platelets, and other cell fragments, molecules, and debris.
  • Deoxygenated blood is a darker shade of red.
  • By volume, red blood cells constitute about 45% of whole blood, plasma about 54.3%, and white cells about 0.7%, with platelets making up less than 1%.

• White Blood Cells

  • White blood cells, also called leukocytes (leuko = white), make up approximately one percent, by volume, of the cells in blood.
  • The role of white blood cells is very different from that of red blood cells.
  • White blood cells are formed continually; some live only for hours or days, while some live for years.
  • The morphology of white blood cells differs significantly from red blood cells.
  • Some white blood cells become macrophages that either stay at the same site or move through the blood stream and gather at sites of infection or inflammation where they are attracted by chemical signals from foreign particles and damaged cells.