Question

1-

Carbon dioxide is carried in the plasma, on hemoglobin, and as bicarbonate ions. What are the percentages of each?

Plasma

hemoglobin

bicarbonate

2- Why is there no N₂ in your blood even though it is the dominant gas in the atmosphere?

3-

Explain the significance of the 2 major regions of the oxygen saturation/desaturation curve, i.e., the flat region & the steep region. 1. what are their ranges? 2. what is Hb's job? 3. at what locations? 4. what is happening with regard to Hb's P_O2 sensitivity? (Hb = hemoglobin)

4-

What exactly is the Bohr effect?

Answer 1

Ans1:-A small portion of the CO2 is transported in the dissolved state to the lungs. Recall that the PCO2 of venous blood is 45 mm Hg and that of arterial blood is 40 mm Hg. The amount of CO2 dissolved in the fluid of the blood at 45 mm Hg is about 2.7 ml/dl (2.7 volumes percent). The amount dissolved at 40 mm Hg is about 2.4 milliliters, or a difference of 0.3 milliliter. Therefore, only about 0.3miilliliter of CO2 is transported in the dissolved form by each 100 milliliters of blood flow. This is about 7 percent of all the CO2 normally transported.

TRANSPORT OF CO2 IN THE FORM OF BICARBONATE ION:-reaction of Carbon Dioxide with Water in the Red Blood Cells due to Effect of Carbonic Anhydrase. The disolved CO2 in the blood reacts with water to form carbonic acid. the carbonic acid formed in the red cells (H2CO3) dissociates into hydrogen and bicarbonate ions (H+ and HCO3−).reversible combination of CO2 with water in the red blood cells under the influence of carbonic anhydrase accounts for about 70 percent of the CO2 transported from the tissues to the lungs.

TRANSPORT OF CO2 IN THE FORM OF CARBHEMOGLOBIN:The quantity of CO2 that can be carried from the peripheral tissues to the lungs by carbamino combination with hemoglobin and plasma proteins is about 30 percent of the total quantity transported.

Ans2:- human inhale nitrogen too with oxygen ,but its not used for human physiology,and it get expired unchanged by human beings.because it s a inert gas

• exactly 1 liter of nitrogen is dissolved in the entire human body. Slightly less than one half of this nitrogen is dissolved in the fluid of the body ,and a little more than one half is dissolved in the fat of the body, because nitrogen is five times more soluable in fat of the body.
• ans3:-

systemic arteries usually has a PO2 of about 95 mm Hg, one can see from the dissociation curve that the usual O2 saturation of systemic arterial blood averages 97 percent. Conversely, in normal venous blood returning from the peripheral tissues, the PO2 is about 40 mm Hg, and the saturation of hemoglobin averages 75 percent.

Hb 'job:-about 97 percent of the oxygen transported from the lungs to the tissues is carried in chemical combination with hemoglobin in the red blood cells. The remaining 3 percent is transported in the dissolved state in the water of the plasma and blood cells. Thus, under normal conditions, oxygen is carried to the tissues almost entirely by hemoglobin.

Hb'po2 sensitivity:-Referring to the O2-hemoglobin dissociation curve in , one can see that for the normal 5 milliliters of O2 to be released per 100 milliliters of blood flow, the PO2 must fall to about 40 mm Hg. Therefore, the tissue PO2 normally cannot rise above this 40 mm Hg level because, if it did, the amount of O2 needed by the tissues would not be released from the hemoglobin. In this way, the hemoglobin normally sets an upper limit on the PO2 in the tissues at about 40 mm Hg.Conversely, during heavy exercise, extra amounts of O2 (as much as 20 times normal) must be delivered from the hemoglobin to the tissues. However, this delivery of extra O2 can be achieved with little further decrease in tissue PO2 because of (1) the steep slope of the dissociation curve and (2) the increase in tissue blood flow caused by the decreased PO2; that is, a very small fall in PO2 causes large amounts of extra O2 to be released from the hemoglobin. Thus, the hemoglobin in the blood automatically delivers O2 to the tissues at a pressure that is held rather tightly between about 15 and 40 mm Hg.

Ans4:-BOHR'sEFFECT:- Shift of the oxygen-hemoglobin dissociation curve to the right in response to increases in blood CO2 and hydrogen ions has a significant effect by enhancing the release of O2 from the blood in the tissues and enhancing oxygenation of the blood in the lungs. This is called the Bohr effect, which can be explained as follows: As the blood passes through the tissues, CO2 diffuses from the tissue cells into the blood. This diffusion increases the blood PCO2, which in turn raises the blood H2CO3 (carbonic acid) and the hydrogen ion concentration.these effects shift the O2-hemoglobin dissociation curve to the right and downward, as shown in Figure 41-10, forcing O2 away from the hemoglobin and therefore delivering increased amounts of O2 to the tissues. Exactly the opposite effects occur in the lungs, where CO2 diffuses from the blood into the alveoli. This diffusion reduces the blood PCO2 and decreases the hydrogen ion concentration, shifting the O2-hemoglobin dissociation curve to the left and upward. Therefore, the quantity of O2 that binds with the hemoglobin at any given alveolar PO2 becomes considerably increased, thus allowing greater O2 transport to the tissues.