Physiology Week 13 Flashcards
(24 cards)
What is the main function of respiration?
Gas exchange to supply oxygen and remove carbon dioxide.
What percentage of oxygen is dissolved in plasma?
Less than 2%.
What protein carries the majority of oxygen in the blood?
Hemoglobin (Hb).
How many oxygen molecules can one hemoglobin molecule bind?
Four.
What is the term for hemoglobin bound to oxygen?
Oxyhemoglobin.
What is hemoglobin saturation in arterial blood at rest?
94-100%.
What is hemoglobin saturation in venous blood at rest?
75%.
What does the oxygen-hemoglobin dissociation curve show?
The relationship between blood PO2 and hemoglobin saturation.
In which region of the dissociation curve does hemoglobin saturation remain stable despite changes in PO2?
Plateau region.
What effect does a decrease in PO2 have on hemoglobin saturation in the steep region of the dissociation curve?
It significantly decreases Hb saturation.
What happens to hemoglobin saturation when tissue PO2 drops to 40 mmHg at rest?
Hb releases about 25% of its oxygen.
What is the effect of exercise on oxygen release?
More oxygen is released due to increased demand, dropping saturation significantly.
What principle explains the sigmoidal shape of the oxygen-hemoglobin dissociation curve?
Positive cooperativity.
What is the most important factor affecting hemoglobin saturation?
PO2 of blood.
What happens to the oxygen-hemoglobin dissociation curve when temperature increases?
It shifts to the right, meaning more oxygen is released.
What is the Bohr effect?
The decrease in hemoglobin’s oxygen affinity due to low pH (high H+ concentration).
What percentage of CO2 is dissolved in plasma?
7%.
What percentage of CO2 is transported bound to hemoglobin?
23%.
What is the primary form of CO2 transport in the blood?
Bicarbonate ions (70%).
What enzyme converts CO2 to bicarbonate in red blood cells?
Carbonic anhydrase.
What is the chloride shift?
The exchange of HCO3⁻ and Cl⁻ to maintain electrical balance in RBCs.
What happens to hemoglobin affinity for oxygen when PCO2 increases?
It decreases, promoting oxygen release.
What happens to CO2 at the pulmonary capillaries?
It diffuses into the alveoli to be exhaled.
What happens when oxygen binds to hemoglobin in the pulmonary capillaries?
It displaces H+ ions, which then react with HCO3⁻ to form CO2 for exhalation.
