hemoglobin

Examples of hemoglobin in the following topics:

• Oxygen Transport

  • Hemoglobin is a protein found in red blood cells (also called erythrocytes).
  • This also means that the approximate carrying capacity for oxygen in hemoglobin has been reached and excess oxygen won't go into hemoglobin.
  • Rightward shifts indicate a decreased affinity for the binding of hemoglobin, so that less oxygen binds to hemoglobin, and more oxygen is unloaded from it into the tissues.
  • Leftward shifts indicate an increased affinity for the binding of hemoglobin, so that more oxygen binds to hemoglobin, but less oxygen is unloaded from it into the tissues.
  • The oxygen–hemoglobin dissociation curve plots the percent hemoglobin saturation (y-axis) against the partial pressure of oxygen in the blood (PO2).

• RBC Physiology

  • Most of these functions are attributed to hemoglobin content.
  • RBCs facilitate gas exchange through a protein called hemoglobin.
  • Oxygen bound hemoglobin is called oxyhemoglobin.
  • Hemoglobin bound oxygen causes a gradual increase in oxygen-binding affinity until all binding sites on the hemoglobin molecule are filled.
  • Hemoglobin can also bind to carbon dioxide, which creates carbamino-hemoglobin.

• RBC Anatomy

  • Hemoglobin molecules are the most important component of RBCs.
  • Hemoglobin is a specialized protein that contains a binding site for the transport of oxygen and other molecules.
  • The RBCs' distinctive red color is due to the spectral properties of the binding of hemic iron ions in hemoglobin.
  • Each human red blood cell contains approximately 270 million of these hemoglobin biomolecules, each carrying four heme groups (individual proteins).
  • Hemoglobin comprises about a third of the total RBC volume.

• Carbon Dioxide Transport

  • CO2 is carried in blood in three different ways: dissolved in plasma, bound to hemoglobin, or as a biocarbonate ion.
  • While oxygen binds to the iron content in the heme of hemoglobin, carbon dioxide can bind to the amino acid chains on hemoglobin.
  • When carbon dioxide clings to hemoglobin it forms carbanimohemoglobin.
  • Dissolved carbon dioxide is already able to diffuse into the alveolus, while hemoglobin-bound carbon dioxide is unloaded into the plasma.
  • Hemoglobin is a tetramer of alpha (red) and beta (blue) subunits with iron containing heme groups (green).

• Sickle-Cell Disease

  • It is caused by a change in hemoglobin's primary structure .
  • Hemolytic crises are acute accelerated drops in hemoglobin level.
  • Abnormal hemoglobin forms can also be detected on hemoglobin electrophoresis, a form of gel electrophoresis on which the various types of hemoglobin move at varying speeds.
  • Sickle cell anemia is caused by a change in hemoglobin's primary structure
  • The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.

• Carbon Monoxide Poisoning

  • This prevents oxygen binding to hemoglobin, reducing the oxygen-carrying capacity of the blood, leading to hypoxia.
  • The oxygen-binding capacity of hemoglobin is shown in Figure 1 .
  • Carboxyhemoglobin (HbCO) can revert to hemoglobin, but the recovery takes time because the HbCO complex is fairly stable.
  • In most vertebrates, the hemoglobin molecule is an assembly of four globular protein subunits.
  • Influence of partial pressure of oxygen on the dissociation of oxygen from hemoglobin at 37 degrees Celsius.

• Anemia

  • Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood resulting in tissue hypoxia.
  • Anemia is a decrease in number of red blood cells (RBCs), or less than the normal quantity of hemoglobin in the blood.
  • It can include the decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin deficiencies.
  • Because hemoglobin (found inside RBCs) normally carries oxygen from the lungs to the tissues, anemia leads to hypoxia (lack of oxygen) in organs.
  • Iron is an essential part of hemoglobin, and low iron levels result in decreased incorporation of hemoglobin into red blood cells.

• Physical Characteristics and Volume

  • Blood contains plasma and blood cells, some of which have hemoglobin that makes blood red.
  • Blood appears red because of the high amount of hemoglobin, a molecule found on RBCs.
  • Each hemoglobin molecule has four heme groups that interact with various molecules, which alters the exact color.
  • In oxygenated blood found in arterial circulation, hemoglobin-bound oxygen creates a distinctive red color.

• Plasma and Blood Volume Expanders

  • Normal human blood has a significant excess oxygen transport capability because not all of the hemoglobin molecules are loaded with oxygen under normal conditions.
  • As long as pulmonary function is sufficient for gas exchange and there is enough blood volume to have sufficient blood pressure, very low hemoglobin levels will be enough to sustain the patient.
  • Those with low hemoglobin content will not be able to tolerate situations where a greater amount of oxygen is required (exercise, for example) until their hemoglobin levels are restored.
  • The body has compensatory feedback mechanisms to deal with lower hemoglobin levels.
  • In extreme cases, patients have survived with a hemoglobin level of about 1/7 the normal (i.e. 2 g/dl), although levels this low are very dangerous.

• Skin Color

  • The amount of oxygen-saturated hemoglobin found in the blood vessels of the middle layer of our skin, the dermis. 
  • Hemoglobin is the iron containing protein pigment of our blood cells. 
  • Skin may also become paler as a result of anemia (a reduced number of hemoglobin and/or red blood cells), low blood pressure, or poor circulation of blood. 
  • Conversely, light skinned individuals (compared to dark skinned ones) may have a rosy effect to their skin thanks to the relatively more obvious oxygen-rich hemoglobin flowing through the blood vessels of the dermis. 
  • As the blood (namely the hemoglobin) disintegrates and is processed and removed by various cells, it (and the bruise) changes color with time.