31. Physiology - Gas Transfer
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Questions and Answers

Which factor will lead to a decreased affinity of hemoglobin for oxygen?

  • Decreased temperature
  • Decreased partial pressure of carbon dioxide
  • Increased pH levels
  • Increased hydrogen ion concentration (correct)

    • What is the primary form in which carbon dioxide is transported in venous blood?

  • Bicarbonate ions (correct)
  • Carbamino compounds
  • Dissolved state
  • Carbonic acid

    • What physiological condition can cause an increased release of oxygen from hemoglobin?

  • Decreased hydrogen ion concentration
  • Increased affinity of hemoglobin for oxygen
  • Increased temperature (correct)
  • Reduced levels of carbon dioxide

    • How does carbon monoxide affect hemoglobin's ability to carry oxygen?

    <p>It occupies oxygen binding sites, reducing oxygen content.</p> Signup and view all the answers

    What is the percentage of carbon dioxide transported in the form of carbamino compounds in arterial blood?

    <p>4%</p> Signup and view all the answers

    What mechanism facilitates the rapid conversion of carbon dioxide to bicarbonate in red blood cells?

    <p>The action of carbonic anhydrase</p> Signup and view all the answers

    What effect does increased carbon dioxide concentration have on hemoglobin's oxygen affinity?

    <p>It decreases oxygen affinity.</p> Signup and view all the answers

    What happens to the oxygen dissociation curve when carbon monoxide binds to hemoglobin?

    <p>The curve shifts to the left.</p> Signup and view all the answers

    Which of the following is NOT a form in which carbon dioxide is transported in the blood?

    <p>Deoxynucleotides</p> Signup and view all the answers

    What is the relationship between exercise and oxygen release from hemoglobin?

    <p>Exercise increases hydrogen ion concentration, facilitating oxygen release.</p> Signup and view all the answers

    What effect does an increase in blood temperature have on the oxyhemoglobin dissociation curve?

    <p>It shifts the curve to the right, decreasing oxygen affinity.</p> Signup and view all the answers

    What is the P50 in the context of hemoglobin oxygen binding?

    <p>The partial pressure of oxygen at which hemoglobin is 50% saturated.</p> Signup and view all the answers

    How does anemia primarily affect the oxyhemoglobin dissociation curve?

    <p>It does not affect the curve but reduces total oxygen content.</p> Signup and view all the answers

    Which enzyme is essential for normal carbon dioxide transport in the blood?

    <p>Carbonic anhydrase</p> Signup and view all the answers

    What physiological change occurs as a result of the Haldane effect?

    <p>Enhanced carbon dioxide transport due to decreased oxygen binding.</p> Signup and view all the answers

    Which two conditions are likely to shift the oxyhemoglobin dissociation curve to the right?

    <p>Increase in temperature and increase in PCO2</p> Signup and view all the answers

    In what form is approximately 70% of carbon dioxide transported in the blood?

    <p>As bicarbonate ions</p> Signup and view all the answers

    Which of the following factors does NOT affect the oxyhemoglobin dissociation curve?

    <p>Hemoglobin concentration</p> Signup and view all the answers

    How does the presence of 2,3-DPG influence hemoglobin's affinity for oxygen?

    <p>It decreases hemoglobin's affinity for oxygen.</p> Signup and view all the answers

    What is the primary method through which oxygen is transported in the blood?

    <p>Combined with hemoglobin</p> Signup and view all the answers

    At a normal partial pressure of oxygen (PO2) of 100 mmHg, how much oxygen is dissolved in 100 ml of blood according to Henry's law?

    <p>0.3 ml</p> Signup and view all the answers

    How is the oxygen content of hemoglobin calculated?

    <p>Hemoglobin concentration multiplied by 1.34 multiplied by the degree of saturation</p> Signup and view all the answers

    What happens to the hemoglobin saturation as PO2 drops below 60 mmHg?

    <p>Saturation decreases significantly</p> Signup and view all the answers

    What is the effect of a rightward shift in the oxyhemoglobin dissociation curve?

    <p>Decreases hemoglobin saturation for a given PO2</p> Signup and view all the answers

    Which of the following statements about oxygen transport is true?

    <p>Oxygen can be transported either dissolved or combined with hemoglobin.</p> Signup and view all the answers

    How much oxygen can a fully saturated hemoglobin molecule bind?

    <p>4 ml</p> Signup and view all the answers

    What is the oxygen content of blood if a male has a hemoglobin concentration of 16 g/100 ml?

    <p>21.44 ml O2/100 ml</p> Signup and view all the answers

    What principle underlies the amount of gas dissolved in plasma according to Henry's law?

    <p>Gas solubility is proportional to the gas's partial pressure</p> Signup and view all the answers

    What is the normal oxygen content of blood?

    <p>20 ml/100 ml of blood</p> Signup and view all the answers

    What is the amount of oxygen dissolved in blood at a normal PO2 of 100 mmHg?

    <p>0.3 ml O2/100 ml of blood</p> Signup and view all the answers

    How is the oxygen content of hemoglobin determined?

    <p>Hemoglobin concentration multiplied by 1.34 multiplied by oxygen saturation</p> Signup and view all the answers

    What significant change occurs in hemoglobin saturation when PO2 drops below 60 mmHg?

    <p>Significant reductions in saturation occur</p> Signup and view all the answers

    What consequence does a rightward shift in the oxyhemoglobin dissociation curve have?

    <p>Decreased saturation of hemoglobin at a given PO2</p> Signup and view all the answers

    How much oxygen can each gram of saturated hemoglobin bind?

    <p>1.34 ml O2/g</p> Signup and view all the answers

    Which factor does NOT lead to a rightward shift in the oxyhemoglobin dissociation curve?

    <p>Increased pH</p> Signup and view all the answers

    What role does bicarbonate play in carbon dioxide transport in the blood?

    <p>It acts as a buffer to maintain blood pH.</p> Signup and view all the answers

    Which of the following correctly describes the effect of carbon monoxide poisoning on oxygen transport?

    <p>It decreases the amount of oxygen that can be released to tissues.</p> Signup and view all the answers

    How does the chloride shift contribute to carbon dioxide transport?

    <p>It facilitates the conversion of carbon dioxide to bicarbonate.</p> Signup and view all the answers

    What is the impact of a decreasing pH on oxygen transport dynamics?

    <p>It promotes oxygen release from hemoglobin to tissues.</p> Signup and view all the answers

    Study Notes

    Oxygen Transport

    • Oxygen is transported in blood by being dissolved in plasma and combined with hemoglobin.
    • The amount of oxygen dissolved in plasma is proportional to the partial pressure of oxygen (PO2), following Henry's Law.
    • Each hemoglobin molecule can bind 4 oxygen molecules, becoming fully saturated when all binding sites are occupied.
    • The oxygen content of blood is determined by hemoglobin concentration, saturation, and the oxygen-carrying capacity of hemoglobin, which is 1.34 ml of oxygen per gram of hemoglobin.

    Oxyhemoglobin Dissociation Curve

    • The oxyhemoglobin dissociation curve shows the relationship between PO2 and hemoglobin saturation.
    • The curve's shape allows hemoglobin to remain close to 100% saturated even with a significant decrease in PO2.
    • Factors that shift the curve to the right decrease hemoglobin's affinity for oxygen, facilitating oxygen release to tissues.
    • These factors include increased temperature, 2,3 diphosphoglycerate (DPG) concentration, partial pressure of carbon dioxide (PCO2), and hydrogen ion concentration.
    • Carbon monoxide poisoning shifts the curve leftward, increasing hemoglobin's affinity for oxygen, impairing oxygen delivery to tissues.

    Carbon Dioxide Transport

    • Carbon dioxide is transported in three forms: dissolved in plasma, as bicarbonate ions, and as carbamino compounds.
    • Carbonic anhydrase, an enzyme located in red blood cells, facilitates the conversion of CO2 to bicarbonate ions (HCO3-).
    • The Haldane effect describes how the binding of oxygen to hemoglobin reduces its affinity for CO2, promoting CO2 release from the blood.
    • The chloride shift, the movement of chloride ions into red blood cells to maintain electrical neutrality, is essential for bicarbonate transport.

    Acid-Base Balance

    • The Kassirer-Bleich equation relates CO2 levels, pH, and bicarbonate concentration.
    • Respiratory acidosis occurs due to a buildup of CO2, while respiratory alkalosis occurs due to low CO2 levels.
    • Metabolic acidosis and alkalosis involve imbalances in HCO3- concentrations.

    Oxygen Transport

    • Oxygen is transported in blood in 2 forms: dissolved in plasma and bound to hemoglobin.
    • Only a small amount of oxygen is dissolved in plasma due to Henry's Law.
    • Hemoglobin binds 4 oxygen molecules per molecule, and can carry significant amounts of oxygen per gram of hemoglobin.

    Oxyhemoglobin Dissociation Curve

    • The oxyhemoglobin dissociation curve shows the relationship between PO2 and hemoglobin saturation.
    • The curve is sigmoidal, meaning that hemoglobin is close to fully saturated even at relatively low PO2.
    • This allows for efficient oxygen uptake in the lungs and delivery to tissues.
    • The P50 value represents the PO2 at which hemoglobin is 50% saturated.
    • Factors that can shift the curve to the right:
      • Increased temperature
      • Increased 2,3-DPG concentration
      • Increased PCO2
      • Decreased pH (increased acidity)
    • These shifts indicate a decreased affinity of hemoglobin for oxygen, facilitating oxygen release to tissues.
    • Carbon monoxide poisoning shifts the curve to the left, increasing hemoglobin affinity for oxygen, but reducing oxygen carrying capacity.

    Carbon Dioxide Transport

    • Carbon dioxide is transported in blood in three forms: dissolved, as bicarbonate, and bound to hemoglobin.
    • Most carbon dioxide is transported as bicarbonate.
    • The enzyme carbonic anhydrase, located in red blood cells, facilitates conversion of carbon dioxide to bicarbonate and hydrogen ions.
    • The Haldane effect describes the interaction between CO2 and O2 binding on hemoglobin: as CO2 increases, the affinity of hemoglobin for oxygen decreases, promoting oxygen release.
    • The chloride shift is important for maintaining electrical neutrality as bicarbonate moves out of red blood cells in exchange for chloride ions.

    Acid-Base Balance

    • The Kassirer-Bleich Equation describes the relationship between respiratory and metabolic acid-base disturbances.
    • Respiratory acidosis is caused by an increase in PCO2; metabolic acidosis is caused by a decrease in bicarbonate.
    • Respiratory alkalosis is caused by a decrease in PCO2; metabolic alkalosis is caused by an increase in bicarbonate.

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    Description

    This quiz covers the mechanisms of oxygen transport in blood, including the roles of plasma and hemoglobin. It also explores the oxyhemoglobin dissociation curve, highlighting how various factors influence hemoglobin's affinity for oxygen. Test your understanding of these essential concepts in respiratory physiology.

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