respiration course pack part 2 (slide 55-100) Flashcards
What is Henry’s law?
What is the O2 consumption per min?
-Henry’s law is the amount of dissolved gas carried by blood is directly proportional to the partial pressure of the gas
-O2 consumption per min is 300ml O2/min
What is essential for O2 transport?
How much O2 is bound to Hb?
Hemoglobin is essential for O2 transport since it allows blood to take up 65x more O2 than plasma, and it combines rapidly and reversibly with O2
-19.5% of O2 in blood is bound to Hb
What contributes to Po2
-only O2 in plasma contributes to PO2
What is the O2 dissociation curve shape?
What is Hb at high and low PO2
-sigmodal curve shape
-at high PO2 Hb is saturated (curve is more flat)
-at low PO2, Hb is deasturated to let O2 go to be available for working tissue of cell metabolism
What is the percent change of HbO2 at low vs high PO2?
-at high PO2 the chnage from 100 to 80mmhg only results in 3% HbO2 change
-at low PO2 change from 40 to 20 mmhg is 40% change
What does myoglobin bind to, where is it found?
What is the shape of the curve, when will it release O2?
-myoglobin only binds 1 O2 molecule, and it is found in skeletal muscle
-the curve shape is hyperbolic, and will only release an O2 at very low PO2
What is the norml amount of Hb in the blood?
14g/100L is the normal amount
What is the Bohr effect, and what happens during exercise in this process?
-Bohr effect is the shift of the HbO2 curve to the right when blood CO2 or temp increase, or pH decreases
-when we excercise we increase CO2 and acid production and produce heat, shifting the curve to the right, meaning when we drop PO2, and extra mount of O2 is released to be used in tissue
-makes O2 available sooner
What does carbon monoxide do, how does it affect the HbO2 curve?
What happens to PaO2?
-CO has a high O2 binding site affinity and will reduce the amount of O2 in Hb, it also shifts the HbO2 to the left decreasing amount of unloading O2 in the tissue
-in CO poisoning PaO2 remains normal so you dont know that you do not have enough O2
How is CO2 carried in the blood, 3 ways that it is carried?
- physically dissolved in the blood (10%)-CO2 from tissues diffuses into the plasma
- combined with Hb to form HbCO2 (11%)-CO2 combines with globin portion
- as bicarbonate (79%)-CO2 combines with H2O to produce carbonic acid, diffuses into erythrocytes with help of carbonic anhydrase then ionizes into bicarbonate (Cl- comes into cell to maintain pH)
What happens in lowering of PCO2?
What happens when PCO2 is higher in blood than alveoli?
-results in HCO3- getting transformed in to H2CO3 and further int o CO2, H2O, and HbCO2 making Hb+CO2
-there is anet diffusion from blood into alveoli which lowers the blood PCO2
What is the haldane effect?
-it is the fact that mixed venous blood can carry more CO2 than can arterial blood, creating more H2CO3 and thus more bicarbonate for CO2 to be in
What is the relationship between CO2 and PCO2 in the graph?
What happens if we double alveolar ventilation?
-it is a linear relationship
For example, if we hypoventilate and alveolar PCO2 rises, then arterial, capillary, tissue and venous CO2 also rises
-it halves alveolar PCO2, so an increase in alveolar ventilation proportionally increase CO2 removal
What are the reasons that can lead to respiratory failure?
due to failure of:
1. the gas exchanging capabilities of the lungs
2. the neural control of ventilation (the drive to breath)
3.the nueromuscular breathing apparatus (respiratory muscles and their innnervation)
what is hypoxia?
It refers to deficient blood oxygen, meaning PaO2 and Hb saturation are low
What are the 5 causes that can lead to hypoxia?
- inhalation of low PO2 (high altitude)
2.hypoventilation - ventilation/perfusion imbalance
4.shunts of blood across lungs
5.O2 diffusion impairment