Transport of gases

• Where does gas exchange occur in the body?

  At the lungs between blood and air, and at tissues between blood and tissues
• How do CO2 and O2 move through the body?

  They move through the bloodstream via the cardiovascular system
• What drives the movement of oxygen into tissues and carbon dioxide into blood?

  The change in partial pressure from the alveoli to the capillaries
• What percentage of oxygen is physically dissolved in plasma?

  2%
• How is oxygen transported in the blood?

  Oxygen is transported dissolved in plasma and chemically bound to hemoglobin
• What is the normal partial pressure of oxygen (PaO2) in arterial blood?

  75 to 100 mm Hg
• What does the oxyhemoglobin dissociation curve illustrate?

  It illustrates how hemoglobin saturation changes with varying partial pressures of oxygen
• What is the Bohr effect?

  The Bohr effect describes how red blood cells adapt to maximize oxygen delivery to tissues
• Why is the Bohr effect important during exercise?

  It helps release more oxygen to tissues that have increased metabolic demand
• What is the effect of carbon monoxide on hemoglobin?

  It binds to hemoglobin with a much higher affinity than oxygen, forming carboxyhemoglobin
• What factors can shift the oxyhaemoglobin dissociation curve to the right?

  Increased pCO2, decreased pH, increased temperature, and high concentrations of 2,3-BPG
• What is the Haldane effect?

  It describes how oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin
• What is the difference between the Bohr effect and the Haldane effect?

  • Bohr effect: Helps tissues release oxygen from oxyhemoglobin
  • Haldane effect: Helps lungs release carbon dioxide from carbaminohemoglobin
• How is carbon dioxide transported in the blood?

  It is transported physically dissolved, as bicarbonate ion, and combined with hemoglobin
• What role does carbonic anhydrase play in carbon dioxide transport?

  It accelerates the formation of carbonic acid from water and CO2 in red blood cells
• How does the CO2 dissociation curve compare to the O2 dissociation curve?

  The CO2 dissociation curve is linear and steep compared to the O2 dissociation curve
• What happens to carbon dioxide when blood is oxygenated in the lungs?

  Carbon dioxide is displaced from hemoglobin, increasing its removal from the blood
• What is the role of bicarbonate ion in carbon dioxide transport?

  It is the primary form in which carbon dioxide is transported in the blood
• What is the significance of the linear shape of the CO2 dissociation curve?

  It indicates that small changes in pCO2 result in significant changes in total CO2 content
• How does the presence of 2,3-BPG affect hemoglobin's oxygen affinity?

  It decreases hemoglobin's affinity for oxygen, promoting oxygen unloading
• How do the Bohr and Haldane effects work together in the body?

  They optimize oxygen delivery to tissues and carbon dioxide removal from the lungs
• What is the effect of acidosis on the oxygen dissociation curve?

  It shifts the curve to the right, promoting oxygen unloading
• What is the significance of the P50 value in the oxyhemoglobin dissociation curve?

  P50 is the partial pressure of O2 required to saturate 50% of hemoglobin with oxygen
• What color is normal arterial blood due to hemoglobin?

  Bright red
• What color is venous blood due to hemoglobin?

  Dark red/Blue
• What color indicates carboxyhemoglobin in patients with CO poisoning?

  Cherry red
• What is the role of Cl- in carbon dioxide transport?

  It exchanges with HCO3- across the RBC membrane to maintain electrochemical equilibrium
• What is the function of the enzyme carbonic anhydrase?

  It accelerates the formation of carbonic acid from water and CO2
• How does the body respond to increased metabolic activity in tissues?

  It increases the release of oxygen from hemoglobin to meet the demand
• How do changes in blood pH affect oxygen transport?

  Decreased pH promotes oxygen unloading from hemoglobin
• What happens to the affinity of hemoglobin for oxygen as pCO2 increases?

  The affinity decreases, promoting oxygen unloading
• What is the primary form of carbon dioxide transport in the blood?

  As bicarbonate ion (HCO3-)
• How does the body maintain electrochemical equilibrium during carbon dioxide transport?

  By exchanging Cl- with HCO3- across the RBC membrane
• How do the Bohr and Haldane effects interact during respiration?

  They facilitate efficient oxygen delivery and carbon dioxide removal in the lungs and tissues
• What is the significance of the steepness of the CO2 dissociation curve?

  It allows for rapid changes in CO2 content with small changes in pCO2
• What is the effect of increased body temperature on the oxygen dissociation curve?

  It shifts the curve to the right, promoting oxygen unloading
• How does the presence of 2,3-BPG affect hemoglobin's oxygen affinity?

  It decreases hemoglobin's affinity for oxygen, facilitating oxygen unloading
• What physiological changes occur during exercise that affect oxygen delivery?

  Increased metabolic rate leads to higher CO2 levels and lower pH, promoting oxygen unloading
• What is the role of hemoglobin in oxygen transport?

  Hemoglobin binds oxygen in the lungs and releases it in tissues
• What is the effect of high concentrations of 2,3-BPG on hemoglobin?

  It promotes the unloading of oxygen from hemoglobin