Hemoglobin is a protein-based component of red blood cells which primary role is transferring oxygen from the lungs to the rest of the body. Although not many people know about this, hemoglobin is actually the reason red blood cells appear red, although oxygen-rich blood is noticeably brighter than the depleted blood returning to the heart and lungs. Fresh hemoglobin is produced in the bone marrow as needed.
Structure of hemoglobin
The hemoglobin molecule is a group of four globular protein subunits and each of these subunits is composed of a protein chain tightly associated with a non-protein heme group. It is proven that each individual protein chain arranges in a set of alpha-helix structural segments connected together in a specific arrangement called myoglobin fold. This folding pattern contains a pocket which is perfectly suitable to strongly bind the heme group.
What exactly is this heme group?
A heme group consists of an iron atom (Fe) held in a heterocyclic ring, known as a porphyrin. This iron atom is the exact site of oxygen binding. The fact is that an iron atom is bonded four nitrogens in the center of the ring and two additional bonds perpendicular to the plane on each side can be formed with the iron to form the fifth and sixth positions, one connected strongly to the protein, the other available for binding of oxygen.
Types of hemoglobins in humans
In the embryo:
Gower 1 (Î¾2Îµ2)
Gower 2 (Î±2Îµ2) (PDB 1A9W)
Hemoglobin Portland (Î¾2Î³2)
In the fetus:
Hemoglobin F (Î±2Î³2) (PDB 1FDH) - Hemoglobin F is the predominant hemoglobin during fetal development
Hemoglobin A (Î±2Î²2) (PDB 1BZ0) - This is the designation for the normal hemoglobin that exists after birth.
Hemoglobin A2 (Î±2Î´2) - This is a minor component of the hemoglobin found in red cells after birth
Hemoglobin F (Î±2Î³2)
The creation of hemoglobin
Like all proteins, the exact copy or blueprint for hemoglobin exists in DNA and normally, every individual has four genes that code for the alpha protein, or alpha chain.Two other genes code for the beta chain. The alpha chain and the beta chain are made in precisely equal amounts, despite the differing number of genes. The protein chains join in developing red blood cells, and remain together for the life of the red cell. The fact is that essentially, hemoglobin develops a hunger for oxygen molecules.
Heme is synthesized in a complex series of steps involving enzymes in the mitochondrion and in the cytosol- two organelles of the cell. First one molecule called 5-aminolevulic acid (ALA) is being transported to the cytosol where a series of reactions produce a ring structure called coproporphyrinogen III which then returns to the mitochondrion where an addition reaction produces protoporhyrin IX. The enzyme ferrochelatase inserts iron into the ring structure of protoporphyrin IX to produce heme.
The fact is that two globin chains combine to form hemoglobin. One of the chains is designated alpha and the second chain is called "non-alpha". This is because there is a number of variables influence the nature of the non-alpha chain in the hemoglobin molecule. For example:
The fetus has a distinct non-alpha chain called gamma.
After birth, a different non-alpha globin chain, called beta, pairs with the alpha chain.
The combination of two alpha chains and two non-alpha chains produces a complete hemoglobin molecule
Physiology of blood and hemoglobin circulation
Whenever the blood is carried into the lungs, these hemoglobin proteins attract whatever oxygen is available and this oxygenated blood then travels throughout the entire bloodstream, releasing oxygen into the various muscles and organs all around the body. When these red blood cells are being spent, they are being transferred to the gastrointestinal system for disposal and new red blood cells with hemoglobin take their place in the bloodstream.
How is hemoglobin measured?
There are several methods exist for measuring hemoglobin and most of them are done currently by machines designed to perform several different tests on blood. In this machine, the red blood cells are broken down to get the hemoglobin into a solution. The free hemoglobin is exposed to some specific chemicals that are containing cyanide which binds tightly with the hemoglobin molecule to form cyanmethemoglobin. By shining a light through the solution and measuring how much light is absorbed, the amount of hemoglobin can be determined.
Normal values of hemoglobin
The hemoglobin level is expressed as the amount of hemoglobin in grams per deciliter of blood and the normal ranges for hemoglobin depend on the age and, beginning in adolescence, the sex of the person. The normal ranges are:
Newborns: 17-22 gm/dl
One (1) week of age: 15-20 gm/dl
One (1) month of age: 11-15gm/dl
Children: 11-13 gm/dl
Adult males: 14-18 gm/dl
Adult women: 12-16 gm/dl
Men after middle age: 12.4-14.9 gm/dl
Women after middle age: 11.7-13.8 gm/dl
How the test is performed?
Hemoglobin levels are amongst the most commonly performed blood tests, usually as part of a full blood count or complete blood count. The test is rather simple. Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand and the puncture site is cleaned with antiseptic. A small needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation and once the blood has been collected, the needle is removed.
Lower-than-normal hemoglobin may indicate:
anemia (various types)
erythropoietin deficiency (from)
red blood cell destruction associated with transfusion reaction
nutritional deficiencies of iron, folate, vitamin B-12, vitamin B-6
Higher-than-normal hemoglobin may indicate:
increased RBC formation associated with excess erythropoietin
What does a low hemoglobin level mean?
Low hemoglobin is referred to the condition called anemia. There are many reasons for anemia. Some of the more common reasons are:
loss of blood (traumatic injury, surgery, bleeding colon cancer),
nutritional deficiency (iron, vitamin B12, folate),
bone marrow problems (replacement of bone marrow by cancer,
suppression by chemotherapy drugs, kidney failure), and
abnormal hemoglobin ()
Possible causes of elevated hemoglobin
A high hemoglobin count usually suggests that you have too many red blood cells. This condition is also called erythrocytosis. It can lead to a several complications because it can impair circulation and lead to abnormal clotting.
An elevated hemoglobin concentration is usually the result of 2 mechanisms:
increased red blood cell production as a compensatory mechanism when blood oxygen carrying capacity is compromised to meet the demand of tissue
contracted plasma volume resulting in an appearance of greater red cell volume
Causes of an elevated hemoglobin count may include:
Living at high altitudes- Because the higher the altitude is, the lower oxygen level is in the air- body is producing more hemoglobin to bind as much oxygen as it is possible!
Smoking- Several studies done in the past with smokers volunteers have proven that great percentage of the smokers have the elevated hemoglobin level, although the mechanism is still unknown. Some experts believe that it could be because of low level of "pure" oxygen in the smoker's lungs! So, this could be an adoptive mechanism on low oxygen levels!
Dehydration - Dehydration produces falsely high hemoglobin which disappears when proper fluid balance is restored.
The symptoms and possible complications
Although much of the clinical focus has been on anemia as a condition where there is lack of hemoglobin, there are also problems at the high end.
The most notable consequence is increased blood viscosity.
Several studies have proven that the relation between hemoglobin and blood viscosity is linear when the hematocrit is <0.50 (equivalent to a hemoglobin value of 160 g/L). Above this hemoglobin concentration, the relation becomes exponential, which means that a small increase in hemoglobin or hematocrit results in a large increase in viscosity. Once hemoglobin concentrations reach 180 g/L, the blood viscosity reaches a level that impairs microcirculation and an inadequate amount of oxygen is transported to tissues, similar to the situation with severe anemia.
Peripheral cyanosis and impaired mental function resulting from compromised cerebral blood circulation are the two most common symptoms of elevated hemoglobin! Additionally, because of the poor blood flow, the risk of thrombo-embolism increases significantly.
Because the high hemoglobin couldn't be considered as a special disorder it could be only treated as a symptom of some other underlying disease. That's why- treating the underlying disease will probably lower the hemoglobin level!
The measure of hemoglobin can be falsely increased with dehydration. The amount of hemoglobin hasn't gone up, but the hemoglobin as a percent of blood volume is elevated when blood volume decreases.
Elevated haemoglobin (shortened to Hb) or a raised haematocrit.
Hemoglobin is glycosylated at any concentration, even normal blood sugar levels. This is why there is a "normal" hemoglobin A1c range. The problem comes when there is an elevated blood glucose. The problem is with the elevated blood glucose, not that there is an elevated Hgb A1c. The A1c is only a marker and a way for physicians to measure the average blood glucose over the past 120 days.
What does high elevated LDL in blood work mean
detects: Mean Corpuscular Hemoglobinmeans average Haemoglobin quantity insuide the Red Blood CellMean corpuscular hemoglobinMean Corpuscular Hemoglobin.It's the avarage mass of hemoglobin in a erytrocyt (red blood cell).A normal value in humans is 27-31 picograms/cell.Converted to SI-units: 1.68 - 1.92 fmol/cell.Ruben Verdoren, biological laboratory studies student.mean corpuscular hb.MCH stands for Mean Corpuscular Hemoglobin. It is a measure of the average amount of hemoglobin in each red blood cell.It's the abbreviation for "Mean Corpuscular Hemoglobin". This is a measure for how much hemoglobin per red blood cell count.MCH stands for Mean Corpuscular Hemoglobin. It is a measure of the average amount of hemoglobin in each red blood cell.
what does 5.8 hemoblobin mean for a african american women
You must mean 11.4. Click in the link below for information about hemoglobin values.
low hemoglobin measurement usually means the person has anemia
It means that your red blood cells are too small an have a small amount of hemoglobin inside. It means you have a kind of an anemia. To make sure what kid of anemia it is, other tests should be performed.
that your hemoglobin levels are normal (13-15). i would be woried if its lower than 12
by dividing the hemoglobin in grams per deciliter by the hematocrit, then multiplying by 100
Elevated RBC and elevated WBC together likely mean the person is dehydrated.
It is slightly elevated which could mean a number of things. If all of you counts hemoglobin, platlets are a little high you could have been a little dehydrated increasing the concentration of cells in the blood. It could mean you have a slight infection. White blood cells are your infection fighting cells. etc...
Elevated Position used in military situations. Situation Squad 1 is approaching an objective. Squad 2 is in a higher position aka Elevated Position.
it means elevated in Hebrew
An elevated lipase level can indicate a problem with the pancreas. It is often ordered in patients with abdominal pain.
To have elevated T4 cells can mean a variety of things. Often times, this means that you have hyperthyroidism. However, this may also be altered if you are pregnant.
It means mean corpuscular hemoglobin concentration, it is a red blood cell index. It tells you the level of hemoglobin in a red blood cell, though this is not as reliable as the mean corpuscular hemoglobin because MCHC depends on the level of hydration of the cell.
Hemoglobin is blood,Ur is urine,ql is Quantity,Large amount of blood in your urine.
The effects of high corpuscular hemoglobin are seen with COPD which can cause difficulty breathing. The most common causes of high hemoglobin are high altitudes and smoking.
This enzyme is elevated in bacterial and fungal meningitis, malignancy, and subarachnoid hemorrhage.
mean corpuscular volume (MCV); mean corpuscular hemoglobin (MCH); mean corpuscular hemoglobin concentration (MCHC); and red cell distribution width (RDW).
MCH is the abbreviated form of mean cell hemoglobin, or the average amount of hemoglobin in the average red cell. MCH is part of the complete blood count and a normal amount of hemoglobin in a red cell is considered to be 27-32 picograms. MCHC is mean cell hemoglobin concentration, or the average concentration of hemoglobin in a given volume of blood. MCHC is also part of the complete blood count and a normal concentration of hemoglobin is considered to be 32-36%.
raised temperature or raised temperarely
It idicates inflamation or infection.
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