Most oxygen is transported bound to haemoglobin in red blood cells. Haemoglobin can bind up to four oxygen molecules to form oxyhaemoglobin. The binding of oxygen to haemoglobin, and release of oxygen from haemoglobin, depends on the partial pressure of oxygen. The oxyhaemoglobin dissociation curve shows that haemoglobin binds oxygen strongly when partial pressure is high in the lungs, and releases it when partial pressure is low in tissues. Factors like temperature, carbon dioxide levels, and pH also affect the oxygen binding capacity of haemoglobin.
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Transport of oxygen (the guyton and hall physiology)Maryam Fida
Supply of oxygen to tissues mainly involves two systems i.e. respiratory system and the cardiovascular system.
Supply of oxygen to tissues depends upon
Adequate PO2 in atmospheric air
Adequate pulmonary ventilation
Adequate gaseous exchange in the lungs
Adequate uptake of oxygen by the blood
Adequate blood flow to the tissues
Adequate ability of the tissues to utilize oxygen
Oxygen diffuses from the alveoli into the pulmonary capillary blood because the oxygen partial pressure (Po2) in the alveoli is greater than the Po2 in the pulmonary capillary blood.
In the other tissues of the body, a higher Po2 in the capillary blood than in the tissues causes oxygen to diffuse into the surrounding cells.
The Po2 of the gaseous oxygen in the alveolus averages 104 mm Hg,
whereas the Po2 of the venous blood entering the pulmonary capillary at its arterial end averages only 40 mm Hg
Therefore, the initial pressure difference that causes oxygen to diffuse into the pulmonary capillary is 104 – 40, or 64 mm Hg.
About 98 percent of the blood that enters the left atrium from the lungs has just passed through the alveolar capillaries and has become oxygenated up to a Po2 of about 104 mm Hg.
Another 2 per cent of the blood which supplies mainly the deep tissues of the lungs and is not exposed to lung air. This blood flow is
called “shunt flow,” meaning that blood is shunted past the gas exchange areas
One gram of Hb can bind 1.34 ml of Oxygen
Normal level of Hb is 15 grams/dL
Thus 15 grams of hemoglobin in 100 milliliters of blood can combine with a total of almost exactly 20 milliliters of oxygen if the hemoglobin is 100 per cent saturated
This is usually expressed as 20 volumes per cent
Hemoglobin is a conjugated protein consisting of heme and globin.
The ferrous form can bind oxygen.
Hemoglobin molecule consists of four subunits each consists of one heme and one polypeptide chain
Each subunit can bind one molecule of Oxygen
Oxygenation is a very rapid and reversible process and it can occur in 0.01 seconds
When PO2 is high, oxygen binds with Hb to form Oxyhemoglbin
When PO2 is low oxygen leaves Hb to form Deoxy Hb.
Factors that shift the oxygen hemoglobin dissociation curve
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Dr. K. Rama Rao
Department of Zoology
Govt, Degree College
TEKKALI; Srikakulam Dt: A.P.
Transport of oxygen (the guyton and hall physiology)Maryam Fida
Supply of oxygen to tissues mainly involves two systems i.e. respiratory system and the cardiovascular system.
Supply of oxygen to tissues depends upon
Adequate PO2 in atmospheric air
Adequate pulmonary ventilation
Adequate gaseous exchange in the lungs
Adequate uptake of oxygen by the blood
Adequate blood flow to the tissues
Adequate ability of the tissues to utilize oxygen
Oxygen diffuses from the alveoli into the pulmonary capillary blood because the oxygen partial pressure (Po2) in the alveoli is greater than the Po2 in the pulmonary capillary blood.
In the other tissues of the body, a higher Po2 in the capillary blood than in the tissues causes oxygen to diffuse into the surrounding cells.
The Po2 of the gaseous oxygen in the alveolus averages 104 mm Hg,
whereas the Po2 of the venous blood entering the pulmonary capillary at its arterial end averages only 40 mm Hg
Therefore, the initial pressure difference that causes oxygen to diffuse into the pulmonary capillary is 104 – 40, or 64 mm Hg.
About 98 percent of the blood that enters the left atrium from the lungs has just passed through the alveolar capillaries and has become oxygenated up to a Po2 of about 104 mm Hg.
Another 2 per cent of the blood which supplies mainly the deep tissues of the lungs and is not exposed to lung air. This blood flow is
called “shunt flow,” meaning that blood is shunted past the gas exchange areas
One gram of Hb can bind 1.34 ml of Oxygen
Normal level of Hb is 15 grams/dL
Thus 15 grams of hemoglobin in 100 milliliters of blood can combine with a total of almost exactly 20 milliliters of oxygen if the hemoglobin is 100 per cent saturated
This is usually expressed as 20 volumes per cent
Hemoglobin is a conjugated protein consisting of heme and globin.
The ferrous form can bind oxygen.
Hemoglobin molecule consists of four subunits each consists of one heme and one polypeptide chain
Each subunit can bind one molecule of Oxygen
Oxygenation is a very rapid and reversible process and it can occur in 0.01 seconds
When PO2 is high, oxygen binds with Hb to form Oxyhemoglbin
When PO2 is low oxygen leaves Hb to form Deoxy Hb.
Factors that shift the oxygen hemoglobin dissociation curve
6) transport of oxygen and carbon dioxdideAyub Abdi
lecture 6: transportaion of both gases need a hemoglobin and part of them are transported by plasma. if Hb is low the saturation of oxygen also low and leads a hypoxia, fatigue, dyspnea, etc. in other hand acidosis can occur.
6) transport of oxygen and carbon dioxdideAyub Abdi
lecture 6: transportaion of both gases need a hemoglobin and part of them are transported by plasma. if Hb is low the saturation of oxygen also low and leads a hypoxia, fatigue, dyspnea, etc. in other hand acidosis can occur.
Once the oxygen diffuses across the alveoli, it enters the bloodstream and is transported to the tissues where it is unloaded, and carbon dioxide diffuses out of the blood and into the alveoli to be expelled from the body. Although gas exchange is a continuous process, the oxygen and carbon dioxide are transported by different mechanisms.
What You’ll Learn to Do
Describe how oxygen is bound to hemoglobin and transported to body tissues
Explain how carbon dioxide is transported from body tissues to the lungs
2. Some oxygen can be transported dissolved in plasma but this is minor (only 3% of oxygen transport). Most oxygen is transported bound to haemoglobin. haemoglobin + oxygen = oxyhaemoglobin . Each haemoglobin molecule can transport four oxygen molecules. When oxygen molecules are bound to haemoglobin they are said to be associated . When they are released they are said to be disassociated . The ODC
3. The reaction where haemoglobin takes up oxygen occurs when the concentration of oxygen is high (e.g. in the lung capillaries) And… the reverse reaction where the oxygen is released occurs when the concentration of oxygen is low (e.g. in the muscle capillaries). The ODC
4. Unfortunately the transport of oxygen is not simple because temperature & CO 2 concentration also effect the ability of haemoglobin to carry O 2 . Plus the fact that haemoglobin does not simply accept oxygen at high concentration and release it at low concentration it does so in a non linear fashion. The association and disassociation of oxygen from haemoglobin can be described with a sigmoidal graph. This graph is known as the oxyhaemoglobin dissociation curve. The ODC
5. This graph shows when the partial pressure of oxygen is high ( as it is in the lung capillaries ) there is a very high saturation of haemoglobin with oxygen. When the partial pressure of oxygen is low ( as it is in the capillaries of the tissues ) there is a low saturation of haemoglobin with oxygen... This means the haemoglobin releases oxygen as it travels from the lungs to the tissues. The ODC
6. The amount of oxygen carried and released by haemoglobin depends not only on the partial pressure of oxygen but also on pH. An increase in carbon dioxide causes a decrease in pH. An acidic environment causes oxygen to dissociate from haemoglobin. Just a small decrease in the pH results in a large decrease in the percentage saturation of the haemoglobin with oxygen. This shift of the curve is called the Bohr effect . The ODC
7.
8. A fetus developing in the uterus must be able to extract oxygen from its mother’s blood. Fetal haemoglobin therefore requires a higher affinity for oxygen than adult haemoglobin (it combines more readily with oxygen). Myoglobin is a pigment found in muscles which acts as an oxygen store and it receives its oxygen from haemoglobin therefore it also has a high affinity for oxygen. The ODC
9. The higher the temperature, the less saturated the blood is with oxygen. This situation often arises during exercise (heat is produced by respiration in muscle cells) The increased temperature causes haemoglobin to release oxygen more readily. The ODC
10. Quick quiz – haemoglobin has increased affinity for oxygen – which way does the curve shift?
11. Quick quiz – haemoglobin of an animal that lives at high altitude would it be to the left or right of this curve?
12. Use Figure 1 to describe how haemoglobin loads and unloads oxygen in the body.
13. Loading of oxygen at high p.p. oxygen / in lungs; Unloads oxygen at low p.p. oxygen / in tissues;