Lecture 44- Respiratory System Part 4 Flashcards
How does the oxygen-hemoglobin saturation curve shift when temperature increases?
Shifts right
Lower affinity for O2 to bind at higher temps
How does the oxygen-hemoglobin saturation curve shift when temperature decreases?
Shifts left
Higher affinity for O2 to bind at lower temps
How does the oxygen-hemoglobin saturation curve shift when pH increases?
Shifts left
Higher affinity for O2 to bind at higher pH/less acidic
How does the oxygen-hemoglobin saturation curve shift when pH decreases?
Shifts right
Lower affinity for O2 to bind at lower pH/more acidic
Why is it harder for O2 to bind at acidic levels/what is happening?
Lactic acid/carbonic acid is building up in exercising muscle=cells become more acidic
Free H+ then binds to hemoglobin so O2 has a harder time to bind which lowers affinity
How does the oxygen-hemoglobin saturation curve shift when CO2 increases?
Right shift
CO2 binds to Hb which lowers affinity for O2 to bind
What is the role of carbonic anhydrase enzyme?
Reversibly transforms CO2 and H2O to a bicarbonate ions (HCO3-) and H+.
This process can occur without the enzyme, but it is sped up much faster with it
Overall, what are the four factors that affect O2 affinity to bind?
What is the main way you achieve all three of these?
- Increase temp
- Decrease pH
- Higher levels of CO2
- High levels of 2,3-BPG
What does 2,3-BPG do?
Increases temp and decreases pH=lower O2 affinity when 2,3-BPG levels are high
Explain when high and low O2 affinity means for the tissues and lungs
When oxygen affinity is low, it’s easier for tissues to access oxygen as it’s released more readily from hemoglobin.
When oxygen affinity is high, hemoglobin binds oxygen more readily, aiding oxygen uptake during respiration in the lungs
What is Acidosis?
When pH decreases=less O2 affinity=right shift
What is Alkalosis?
When pH increases=more O2 affinity=shifts left
If the blood is too acidic, what direction will carbonic anhydrase make ions combine with?
H+ and HCO3- combine to break into CO2 and H2O
If the blood is too basic, what direction will carbonic anhydrase make ions combine with?
CO2 and H2O will combine to break into H+ and HCO3-
What law explains diffusion into tissues based on partial pressure?
Fick’s Law
Why does hemoglobin give up oxygen in the tissues?
pH change
Bohr effect
What is the Bohr effect
Explains how pH affects the binding of oxygen to hemoglobin
How does a lower pH affect Hb’s affinity for oxygen? Where does O2 go as a result?
Lower pH (acidic conditions) reduces hemoglobin’s affinity for oxygen, aiding oxygen release in tissues
How does a higher pH affect Hb’s affinity for oxygen? Where does O2 go as a result?
Higher pH (alkaline conditions) increases hemoglobin’s affinity for oxygen, enhancing oxygen uptake in the lungs
What is the Haldane effect?
How does it alter CO2 and O2 affinity?
How oxygen concentrations determines hemoglobin’s affinity for CO2
Binding of O2 displaces CO2 which reduces Hb’s affinity for CO2 and increases affinity for O2
Left shift
How is O2 and CO2 mainly transported?
O2- hemoglobin
CO2- bicarbonate
How does a higher partial pressure of CO2 affect bronchioles diameter?
Diameter increases (bronchodilation)
this aids in ventilation to remove excess CO2 from the body
How does a lower partial pressure of CO2 affect bronchioles diameter?
Diameter decreases (bronchoconstriction)
Helps retain CO2 in the body
When is gas exchange more engaged?
High or low PCO2?
High PCO2
Bronchodilation with high PCO2=less resistance
What is the chloride shift/where does it take place?
The chloride shift refers to the movement of chloride ions into red blood cells (RBCs) in exchange for bicarbonate ions during gas exchange in tissues
What is reverse chloride shift/where does it take place?
Reverse chloride shift occurs in the lungs, where chloride ions move out of RBCs and bicarbonate ions move back in, helping to prepare blood for CO2 exhalation
