Transport of Oxygen and Carbon Dioxide in blood

How is most O₂ transported in the blood?

bound to haemoglobin

What determines how strongly Hb binds O₂?

po2, co2, temperature, dpg

What happens to Hb affinity for O₂ when PO₂ is high?

affinity increases, hb takes up more o2

What happens to Hb affinity for O₂ when PO₂ is low?

affinity decreases, hb releases more o2

What does the oxygen dissociation curve show?

relationship between po2 and hb o2 saturation

What shape is the oxygen dissociation curve?

s shaped

What happens to Hb in the lungs?

high po2, high hb affinity, o2 loaded onto hb

What happens to Hb at the tissues?

lower po2, lower hb affinity, o2 released

What is the Bohr shift?

decrease in haemoglobins affinity that causes more o2 to be released to tisses

What factors cause the Bohr shift?

increases in co2, temperature, dpg, h

What happens to Hb affinity during the Bohr shift?

decreases

What is the result of decreased Hb affinity?

more o2 unloaded to tissues

Why is the Bohr shift useful at active tissues?

active tissues have more co2, h and heat, so releases more o2

What happens to Hb affinity for O₂ when CO₂ increases?

decreases

What happens to Hb affinity when H⁺ increases?

decreases

What happens to Hb affinity when temperature increases?

decreases

What happens to Hb affinity when DPG increases?

decreases

What conditions favour O₂ loading in the lungs?

high po2, low co2, low h, lower temperature, lower dpg

What conditions favour O₂ unloading at tissues?

low po2, high co2, high h, higher temperature, higher dpg

What is the simple difference between the lungs and tissues?

lungs load o2, tissues unload o2

What does "a" represent on the O₂ dissociation curve?

arterial blood

What does "v" represent?

venous blood

Why does venous blood have a lower PO₂ than arterial blood?

o2 has been unloaded to the tissues

Why does arterial blood have a higher PO₂?

just passed through the lungs and loaded o2

What percentage of atmospheric air is O₂?

21%

What is the atmospheric PO₂ at 760 mmHg?

159mmhg

A tissue has increased CO₂, H⁺ and temperature. What happens to Hb?

affinity decreases, o2 released

A tissue becomes more metabolically active. What happens to O₂ unloading?

increases due to bohr shift

If Hb affinity for O₂ increases, does Hb load or unload more O₂?

loads more o2

If Hb affinity for O₂ decreases, does Hb load or unload more O₂?

unloads more o2