Row 1
This percentage represents the approximate amount of total oxygen in the blood that is dissolved rather than bound to hemoglobin.
What is 2%?
The process by which the respiratory system ensures that ventilated alveoli are near perfused pulmonary capillaries.
What is V/Q matching?
In blood, CO₂ acts as this type of molecule when dissolved (forming carbonic acid).
What is an acid?
The name of the respiratory center, located in the dorsal respiratory group (DRG) neurons in the medulla, that controls the basic rhythm (frequency) of breathing.
What is the Inspiratory Center?
This condition is defined simply as a decrease in arterial PO2.
What is Hypoxemia?
This clinical measurement uses dual-wavelength spectrophotometry to measure the percentage saturation of arterial blood, usually reporting a normal value of greater than 95%.
What is Pulse Oximetry?
Pulmonary blood flow is directly proportional to the pressure gradient between the pulmonary artery and this specific heart chamber.
What is the left atrium?
The acid-base abnormality that results from hyperventilation, causing a lowering of blood CO₂ and reduced acidity.
What is respiratory alkalosis?
This center, located in the upper pons, turns off inspiration, limiting the size of the tidal volume (TV) and regulating the respiratory rate (RR).
What is the Pneumotaxic Center?
The three non-pulmonary causes of hypoxia listed, which include anemia, ischemia, and CO poisoning, all result in a decreased delivery of O₂ to the tissues due to a decrease in this overall factor.
What is O₂ content (or O₂ delivery to the tissues or cardiac output)?
In the lungs, where PaO₂ is 100 mmHg, the O₂-Hb curve is on the flat part, indicating that the affinity of hemoglobin for O₂ is highest, which facilitates this process.
What is loading of O₂?
A V/Q ratio of infinity ($\infty$) is characteristic of this type of mismatch, often seen when ventilation is present but there is no blood supply, such as in a pulmonary embolism.
What is Dead space?
The diffusion of CO₂ into red blood cells results in the rapid hydration of CO₂ to H₂CO₃ via carbonic anhydrase, followed by the dissociation of H₂CO₃ into H⁺ and this ion, which then moves into the plasma.
What is HCO₃⁻ (Bicarbonate)?
Located in the ventral medulla, these specific chemoreceptors are the most important for the minute-to-minute control of breathing and are sensitive to changes in the pH of the CSF.
What are Central chemoreceptors?
At high altitude, the resulting hypoxemia triggers the renal synthesis of this hormone, which leads to polycythemia (an increase in red blood cells).
What is Erythropoietin (EPO)?
The binding of Carbon Monoxide (CO) to hemoglobin causes the O₂-Hb dissociation curve to shift left, which has this effect on the affinity of the remaining Hb sites for O₂.
What is increased affinity for O₂?
V/Q & Flow
In the distribution of pulmonary blood flow, this zone is characterized by flow being driven by the difference between arterial pressure and venous pressure ($P_{arterial} - P_{venous}$).
What is Zone 3?
This effect describes the increased capacity of deoxygenated hemoglobin to bind and carry CO₂, facilitating CO₂ uptake in the tissues.
What is the Haldane Effect?
These receptors are located in the alveolar walls near the capillaries and are activated by the engorgement of pulmonary capillaries, resulting in an increase in the respiratory rate.
What are J receptors (Juxtacapillary receptors)?
Hypoxemia caused by high altitude and hypoventilation is differentiated from hypoxemia caused by diffusion defects or R to L shunts because the former two causes result in a value that is considered normal.
What is the Alveolar-arterial (A–a) gradient?
An increase in 2,3-DPG, temperature, and PCO₂, along with a decrease in pH, collectively cause the O₂-Hb dissociation curve to shift in this direction, facilitating O₂ unloading in the tissues.
What is a Right Shift (or Decreased Affinity)?
A V/Q ratio of zero (0) results in this type of shunt, which causes hypoxemia that is specifically characterized by not being corrected with supplemental O₂.
What is an R to L shunt?
Hypocapnia, the result of hyperventilation, causes a decrease in cerebral blood flow due to this specific vascular mechanism.
What is vasoconstriction?
The Inspiratory Center (DRG) receives input from peripheral chemoreceptors (located in the carotid bodies) via these two specific cranial nerves.
What are CN IX and X?
In response to exercise, the O₂-Hb curve shifts to the right, which corresponds to an increase in this parameter and a decrease in the affinity of Hb for O₂.
What is P50?