Lecture 12 Flashcards
Hemoglobin is composed of how many subunits?
4
Which term is used to describe hemoglobin with only one molecule of oxygen bound to it?
Oxyhemoglobin
Carbon dioxide is transported in different forms in the blood. What is the most common form?
Bicarbonate ion
what are the forms CO2 is transported?
(1) carbonic acid
(2) carbamino compounds –> bound to hemoglobin as carbaminohemoglobin
(3) dissolved gas
How is most carbon dioxide transported in the blood?
As bicarbonate
What does oxygen bind to in the hemoglobin molecule?
heme group
True or false: The majority of dissolved carbon dioxide in the blood is transported as carbaminohemoglobin.
false
majority is transported as carbonic acid
Hemoglobin that is not bound to oxygen is called ______.
deoxyhemoglobin
Which term refers to the exchange of gases (O2 and CO2) that occurs in the capillary networks between the blood and the body’s cells?
Systemic gas exchange
According to this oxyhemoglobin dissociation curve, how much of the oxygen bound to hemoglobin is released into the tissues as the blood flows through the systemic capillaries?
22%
Which is true about carbon dioxide loading?
Carbonic anhydrase catalyzes the conversion of CO2 and H20 into bicarbonate and hydrogen ions.
Choose all the forms in which carbon dioxide is transported in the blood.
Dissolved gas
Bicarbonate ion
Carbaminohemoglobin
The enzyme found in erythrocytes that catalyzes the formation of carbonic acid, which then dissociates into bicarbonate and hydrogen ions, is ___ anhydrase.
carbonic
Most carbon dioxide in the blood is transported in the form of ______ dissolved in the plasma.
bicarbonate
Choose all that occur during the “chloride shift” in red blood cells.
Chloride ions are transported into the RBC.
Bicarbonate ions are transported out of the RBC.
True or false: All of the oxygen transported in the blood is usually unloaded at a systemic capillary.
false
Where does systemic gas exchange occur?
At the capillary networks of the tissues
Where is most carbon dioxide loaded into the blood?
Systemic capillary beds
Oxygen loading in the lungs decreases hemoglobin’s affinity for H+. How does this promote alveolar gas exchange?
The released H+ combines with HCO3- to form free CO2, which can diffuse out of the blood.
Which best describes the action of carbonic anhydrase?
It converts carbon dioxide and water to carbonic acid which dissociates into bicarbonate and hydrogen ions.
what are the 4 factors that stimulate oxygen unloading in response to metabolic rates of different tissues?
(1) lowered P O2 –> lower P O2 == releases more oxygen
(2) higher temp temp –> higher temp == more oxygen unloading
(3) lower pH –> (Bohr effect) lower pH == more oxygen unloading
(4) increased BPG –> increased BPG == more oxygen unloading