plz..explain transport of oxygen & transport of carbon dioxide in our body???
Oxygen and carbon dioxide are transported in the body by the blood. Both oxygen and carbon dioxide bind with the haemoglobin of red blood cells to form intermediate compounds called oxyhaemoglobin and carbaminohaemoglobin. Carbon dioxide also dissolves in the plasma to some extent. The gases are exchanged between blood and cells depending upon their respective partial pressure. They flow from their higher partial pressure to lower partial pressure by detaching from the haemoglobin molecule.
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TRANSPORT OF CARBON DIOXIDE-
co2 is transported in our body by many ways;
23% by the carbaminohaemoglobin, after the delivery of oxygen to the tissues the glucose is oxidised in the body cells and cabondioxide is released. due to this partial pressure of this gas increases and it binds with haemoglobin to form carbaminohaemoglobin which then goes up to lungs.
70% by the HCO3- bi carbonate ions;
during the course of respiration carbondioxide gas is released and this gas is is very diffusible gas,
=so it gets into RBC's and react with water in presence of carbonic anhydrase to form H2Co3 and it breks into H+ ions and HCO3-. . in RBC's heamoglobin catch H+ ions to prevent acidic ph inside rbc. this HCO3- goes to lungs.
7% in the form of blood plasma protiens- remaining 7% of the carbon dioxide released from the cells goes into blood plasma and transported in the body.
TRANSPORT OF OXYGEN-
= as the partial pressure of oxygen gas is high in the alveoli of the lungs so haemoglobin releases all the carbon dioxide and binds with the oxygen to form oxyhaemoglobin which transport oxygen to the whole body cells.
othet remaining 3% of the oxygen is transported by the blood plasma in our whole body
Carbon Dioxide Transport
General Cell Metabolism
Cell metabolism is based on the same general principle as the combustion of any fuel, whether it be in the automobile, power plant, or a home furnace. The general combustion reaction is:
CH2O (fuel) + O2 ===> CO2 + HOH
The same reaction occurs in the cells. The "fuel" comes from food in the form of carbohydrates, fats, and proteins.
The important principle to remember is that oxygen is needed by the cell and that carbon dioxide is produced as a waste product of the cell. Carbon dioxide must be expelled from the cells and the body.
The lungs serve to exchange the two gases in the blood. Oxygen enters the blood from the lungs and carbon dioxide is expelled out of the blood into the lungs. The blood serves to transport both gases. Oxygen is carried to the cells. Carbon dioxide is carried away from the cells.
Partial pressures are used to designate the concentrations of gases. Dalton's Law of Partial Pressures states that the total pressure of all gases is equal to the sum of the partial pressures of each gas. For example, the total atmospheric pressure of air is 760 mm Hg. In equation form:
P(total air) = P(O 2) + P(N2) + P(CO2) + P(HOH)
The partial pressures for oxygen and carbon dioxide in various locations are given in Figure 1. The movement or exchange of gases between the lungs, blood, and tissue cells is controlled by a diffusion process.
The gas diffusion principle is: A gas diffuses from an area of higher partial pressure to an area of lower partial pressure.
QUES. Starting with O2 in inhaled air, describe in your own words the sequence of gas movements from the inhalation of oxygen to the exhalation of carbon dioxide.
In the lungs, oxygen diffuses from alveolar air into the blood because the venous blood has a lower partial pressure. The oxygen dissolves in the blood. Only a small amount is carried as a physical solution (0.31 ml per 100 ml). The remainder of the oxygen is carried in chemical combination with the hemoglobin in red blood cells (erthrocytes).
Hemoglobin (molecular weight of 68,000) is made from 4 hemes, a porphyrin ring containing iron and globin, a 4 protein chains. Oxygen is bound to the iron for the transport process. Hemoglobin (HHgb) behaves as a weak acid (K = 1.4 x 10-8; pKa = 7.85). Oxyhemoglobin (HHgbO2) also behaves as a weak acid (K = 2.5 x 10-7; pKa = 6.6)
Because both forms of hemoglobin are weak acids, and a relationship of the numerical values of the equilibrium constants, the net reaction for the interaction of oxygen with hemoglobin results in the following equilibrium:
HHgb + O 2 <===> HgbO 2 + H+
If 2 is increased in the blood at the lungs, the equilibrium shifts to
Oxyhemoglobin can be caused to release oxygen by the addition of H+ ions at the cells. The difference in pH (7.44) of arterial blood and venous blood (pH = 7.35) is sufficient to cause release of oxygen from hemoglobin at the tissue cells.
transport of O2 - 97 percent o2 is found in R.B.C with Hb as oxyhimoglobin. 3 percent O2 transports in plazma.
in this process 3 atom molecules combine with one Hb molecule. Partial pressures of O2 is much then CO2. the Fe+2 of Hb doesn't transform in Fe+3.thus, it trnsports in our blood.
transport of CO2 - CO2 combines with Hb & makes Carbaminohimoglobin. In the cells it combines with water & then makes carbonil acid & it transforms into bicarbonate .in this bicarbonate form it circulates in our blood.In this processPartial pressures of O2 is much then CO2.