Topic D.6: Transport of Respiratory Gases

Essential Idea:  Red blood cells are vital in the transport of respiratory gases.

At SHS, Topic D.6 is taught in the following class unit(s):

• Cell Cycle and Cancer (unit 6B)
• The Respiratory System (unit 46A)
• Transport of Respiratory Gases (unit 46B)

Statements & Objectives:

D.6.U1  Oxygen dissociation curves show the affinity of hemoglobin for oxygen.

• Define partial pressure.
• State the relative partial pressures of oxygen  in the atmosphere at sea level, in the alveoli, in alveoli blood capillaries, and in respiring tissue.
• Define affinity.
• Describe the saturation of hemoglobin at different oxygen partial pressures.
• Draw the oxygen dissociation curve to show affinity of hemoglobin for oxygen at different partial pressures of oxygen
  

D.6.U2  Carbon dioxide is carried in solution and bound to hemoglobin in the blood.

• State the three ways carbon dioxide is carried in the blood.
• State which form of carbon dioxide transport accounts for the highest amount of carbon dioxide transported.  

 D.6.U3  Carbon dioxide is transformed in red blood cells into hydrogen carbonate ions.

• Outline the reaction that transforms carbon dioxide into hydrogencarbonate ion, including the role of carbonic anhydrase.

D.6.U4  The Bohr shift explains the increased release of oxygen by hemoglobin in respiring tissues.

• Explain the mechanism and benefit of the Bohr shift.

D.6.U5  Chemoreceptors are sensitive to changes in blood pH.

• Outline the location and role of chemoreceptors that help regulate the ventilation rate.

D.6.U6  The rate of ventilation is controlled by the respiratory control centre in the medulla oblongata.

• List the neural structures that control the rate of ventilation.
• Outline the feedback loop that regulates the rate of ventilation, including the role of stretch receptors.

D.6.U7  During exercise the rate of ventilation changes in response to the amount of CO2 in the blood.

• ​Describe the relationship between carbon dioxide concentration and blood pH.
• State the effect of exercise on CO2 production.
• Outline the relationship between CO2 production and blood pH.
• Explain how and why hyperventilation occurs in response to exercise.

D.6.U8  Fetal hemoglobin is different from adult hemoglobin allowing the transfer of oxygen in the placenta onto the fetal hemoglobin.

• Compare the oxygen dissociation curves of adult and fetal hemoglobin.
• State the reason why it is adaptive for fetal hemoglobin to have a higher oxygen affinity than adult hemoglobin.

D.6.A1  Consequences of high altitude for gas exchange.

• State the effect of altitude on the atmospheric partial pressure of oxygen.
• Outline human physiological responses to high altitude.

D.6.A2  pH of blood is regulated to stay within the narrow range of 7.35 to 7.45.

• State the range of normal human blood pH.
• Describe the relationship between carbon dioxide concentration and blood pH.
• Outline physiological responses that maintain blood pH.

D.6.A3  Causes and treatments of emphysema.

• Outline the causes of emphysema.
• State the symptoms of emphysema.
• Outline reasons why gas exchange and ventilation are less effective in people with emphysema.
• List treatment options for people with emphysema.

D.6.S1  Analysis of dissociation curves for hemoglobin and myoglobin.

• Contrast myoglobin and hemoglobin.
• Compare the oxygen dissociation curves of hemoglobin and myoglobin.

D.6.S2  Identification of pneumocytes, capillary endothelium cells and blood cells in light micrographs and electron micrographs of lung tissue.

• Label the following structures on a micrograph of lung tissue:  type 1 pneumocyte, type 2 pneumocyte, capillary endothelium, basement membrane and blood cells.

D.6.NOS  Scientists have a role in informing the public—scientific research has led to a change in public perception of smoking.

• Describe how scientific evidence about the effects of smoking lead to a change in public perception of smoking.

In the News:

• Feeling blue: US woman treated by doctors after blood turned navy (2019-09-19)
• ​How the people of the Andes evolved to live in high altitudes (2018-11-08)
• ​New study captures ultrafast motion of proteins (2016-05-23)
• With help from extinct humans, Tibetans adapted to high altitudes (2014-07-02)
• Medical complications cut Everest research expedition short (2016-05-17)
• Two weeks in the mountains can change your blood for months (2016-10-13)
• Mutations may reveal how Tibetans can live on world’s highest plateau (2017-04-03)
• Into more thin air: Exploring the adaptation extremes of human high altitude sickness and fitness (2017-09-21)