02 transportation Flashcards
Blood plasma
oxygen is dissolved in plasma, O2 exert a partial pressure then.
quantity of O2 dissolved in plasma is following Henry’s Law.
Hemoglobin
O2 does not exert a PP once bound to hemoglobin
methemoglobin
caused by Drugs, this causes the O2 to be irreversibly bound to hemoglobin this is due to the oxidation of ferrous iron to ferric iron,
Commonly caused by nitrite poisoning
Gives blood a characteristic brownish color
Patient’s appear slate-grey
May be treated with methylene blue
Bohr Effect
this is the relation btw CO2 and H+ on uptake and release of O2 from Hgb molecule ( relative a mild effect)
increase CO2 and [H+] decreases affinity for O2 at the cell
decrease CO2 and [H+] increases affinity for O2 at the lung
Haldane Effect
this is the relation btw Hgb and CO2
If PO2 increases then it will decreases hemoglobin ability to carry CO2. ( . This allows for large volumes of CO2 to be released at the pulmonary capillary)
If Pressure of O2 decreases then Hgb ability to carry CO2 will increase.(. This allows for a large volume (200 ml/min) of CO2 to be picked up at the systemic capillary bed ) what this means is
Deoxygenated blood enhances loading of carbon dioxide - at the tissue
Oxygenated blood enhances unloading of carbon dioxide - at lung level
right shift (the curve)
low PH and increase in H+ high temperature high pressure of CO2 and increase in 2,3-DPG this results in a decrease in affinity for O2 (lower sat)
Left Shift
increase PH, low H+ low temperature low PCO2 low 2,3-DPG increases affinity for oxygen to exist
2,3 diphosphoglycerate
Contained in RBC’s
metabolic intermediary from anaerobic glycolysis, stabilizes reduced Hgb
causes right shift as levels of 2,3 DPG increase
stored blood has low concentrations of 2,3 DPG
hypoxia increases levels of 2,3-DPG
increase 2,3-DPG causes a right shift of the curve and decreased affinity for oxygen
dyshemoglobin
Abnormalities are usually in the globin portion of the molecule and variably affect affinity for oxygen
Sickle cell anemia (HgbS) is a genetically determined anomaly
the deoxygenated form can crystallize within the RBC causing the classic C-shape
this also increases the fragility of the RBC increasing the risk of thrombus formation
carbon monoxide hemoglobin
affinity of hemoglobin for CO increased to ~210-250 times greater than O2
Does NOT favor releasing CO for many hours
- treatment is hyperbarics
total oxygen delivery- DO2
DO2 is the amount of oxygen delivered to peripheral tissue each minute
O2 delivery is controlled by Qt, Hb concentration, Hb saturation, and dissolved oxygen in that order.
what is the normal arterial and venous content
arterial is 20 % and venous is 15%. difference is 5%
venous content taken at the pulmonary artery
factors that affect VO2
increase VO2- anything that that increases metabolic rate
(exercise,hyperthermia, seizures shivering)
decrease in VO2- slows down metabolic rate
hypothermia, thrombus, peripheral shunting, some poisons.
factors affecting oxygen extraction ratio
oxygen extracted by peripheral tx/ oxygen delivered
increased ratio could be du exercise, seizure, shivering) , decreased in Qt, decreased in arterial oxygenation)
decreased ratio- skeletal muscle relaxants, peripheral shunting, hypothermia, polycythemia.
respiratory quotient
Oxygen is consumed in this process just discussed as well as CO2 produced
CO2 production = 200 ml/min
O2 consumption = 250 ml/min
CO2 produced/ O2 consumed per min
