Respiratory Flashcards
What are the two methods of transporting oxygen in the blood?
Via hemoglobin of erythrocytes and dissolved in blood
What percent of oxygen is transported in the blood directly in the bloodstream? By hemoglobin?
~1.5%; ~98.5%
What is the portion of hemoglobin that contains iron to bind to oxygen? How many iron irons does each hemoglobin molecule have?
Heme; four iron ions to carry up to four oxygen molecules at a time
What is oxyhemoglobin?
When oxygen binds to hemoglobin
What is a conformational change and when does it occur? What does this allow?
Occurs when the first oxygen molecule binds at the alveoli; allows the second molecule of oxygen to bind more readily. (increasing affinity for oxygen)
Does hemoglobin have increasing or decreasing affinity at the tissues?
Decreasing affinity for easy dissociation
What does it mean for a hemoglobin to be 100% saturated? What are the normal values?
When all four heme sites are occupied; 95-100%
What is it called when 1-3 heme sites are occupied?
Partially saturated
Where do we prefer to be more saturated: lungs or tissues?
Lungs, to keep pulling in oxygen
Why is it important to be less saturated in veins and contracting skeletal muscles?
To be able to drop off oxygen more efficiently
Where is percent saturation lowest in the body: systemic arteries, systemic veins, or contracting skeletal muscles? Why?
Contracting skeletal muscles; since muscles are at work, more mitochondria is present and more oxygen needs to be used/dropped off.
What happens to the affinity of heme in the oxygen-Hb saturation curve as partial pressure of oxygen increases?
There is a greater number of oxygen bound to heme (vice versa: lower partial pressure of oxygen means fewer oxygen molecules bound to heme)
What is the partial pressure of oxygen inside arteries and capillaries?
~100 mmHg
Where is the lowest partial pressure of oxygen located? (~40 mmHg)?
Inside veins
Do highly active tissues (exercising muscle) have higher or lower partial pressure of oxygen than less active tissue (adipose)?
Highly active tissue = more oxygen used so lower affinity and LOWER PARTIAL PRESSURE (~20 mmHg in highly active vs ~55-60 mmHg in less active)
What causes hemoglobin and oxygen to dissociate faster, higher temperature or lower temperature? Why?
Higher temperature, as that means more movement is occuring and we need more oxygen to sustain working tissues.
Lower temperature shifts the oxygen-Hb dissociation curve to the left: true or false?
True.
What does elevated 2,3-diphosphoglycerate (DPG) mean for oxygen and hemoglobin?
Higher DPG means making more ATP via glycolysis, so more movement and hence more dissociation.
Does dropping off oxygen make the blood more or less acidic? What happens to pH?
Less acidic; dropping off oxygen means raising pH and correcting for acidosis (low pH)
What relationship does the Bohr effect describe?
pH and oxygen’s affinity for hemoglobin.
During exercise, what happens to the oxygen-Hb dissociation curve? What factors affect it?
Curve shifts right because affinity for oxygen decreases; exercise means more carbon dioxide, more H+ produced, more DPG, and higher temperature
What are the three methods CO2 is transported in the blood?
Bicarbonate, blood plasma, hemoglobin
70% of CO2 is transported in the blood via?
Bicarbonate
What term describes the exchange of chloride ions for bicarbonate when too much bicarbonate builds up in the erythrocytes and it needs to move down its concentration gradient into the plasma?
The chloride shift.
