38 Questions
What is the primary mechanism that allows oxygen to cross the alveoli and re-oxygenate the blood in the pulmonary vasculature?
Diffusion
What percentage of oxygen that dissolves in the blood combines with the oxygen-carrying protein hemoglobin?
99%
What is the primary factor that determines the delivery of oxygen to a particular tissue?
All of the above
What is the term for the volume of oxygen delivered to the systemic vascular bed per minute?
Oxygen delivery
What is the direction of flow of oxygen and carbon dioxide in the lung?
From higher to lower partial pressures
What is the percentage of CO2 that dissolves in the blood and enters into a series of reversible chemical reactions?
94.5%
What two systems are necessary for the ability to deliver oxygen in the body?
Respiratory and circulatory
What happens to the curve when there is a rise in temperature or a fallen pH?
It shifts to the right
What is the significance of p50 in relation to hemoglobin and O2 binding?
It is the pO2 at which hemoglobin is half saturated with O2
What is the minimum concentration of reduced hemoglobin required for cyanosis to appear?
5 g/dL
What is the term for the bluish discoloration of the tissues due to reduced hemoglobin?
Cyanosis
What is the effect of a fallen temperature on the O2 dissociation curve?
It shifts the curve to the left
What determines the occurrence of cyanosis?
The total amount of hemoglobin, the degree of hemoglobin unsaturation, and the state of the capillary circulation
What is the significance of a higher p50 value?
It indicates a lower affinity of hemoglobin for O2
What is the primary function of increased myoglobin in high-altitude adaptation?
To facilitate the movement of oxygen into the tissues
What is the characteristic of the natives who live in high-altitude villages?
They are remarkably normal with low alveolar po2 values
What is the purpose of carbon monoxide in the body?
It functions as a chemical messenger in the brain and elsewhere
What is the result of incomplete combustion of carbon outside the body?
The formation of carbon monoxide
What is the significance of the existence of permanent human habitations in the Andes and Himalayas at elevations above 5,500 m?
It indicates the effectiveness of the acclimatization process
What is the characteristics of the chest of natives who live in high-altitude villages?
They are barrel-chested
What is the historical use of carbon monoxide?
As a method of execution
What is the primary reason why CO poisoning has become less common in the United States?
Increased use of natural gas
What is the name of the compound formed when CO reacts with hemoglobin?
Carboxyhemoglobin (COHb)
Why is CO poisoning considered a form of anemic hypoxia?
Because CO reduces the amount of hemoglobin available for O2 transport
What is the approximate ratio of the affinity of hemoglobin for CO to its affinity for O2?
210 times
Why does the presence of COHb shift the dissociation curve of HbO2 to the left?
Because COHb decreases the amount of O2 released from HbO2
Why is oxygen treatment of limited value in hypoperfusion, anemic, and histotoxic hypoxia?
Because it can only increase the amount of dissolved oxygen in the arterial blood
In which type of hypoxia is oxygen treatment of great benefit?
Other forms of hypoxia
What is the effect of COHb on the amount of hemoglobin available for O2 transport?
It decreases the amount of hemoglobin available for O2 transport
Why is an individual with 50% of the normal amount of HbO2 incapacitated by the formation of COHb?
Because they already have a low amount of hemoglobin available for O2 transport
What is the effect of CO on the transport of O2 in the blood?
It reduces the amount of O2 transported in the blood
Which type of hypoxia is characterized by a normal arterial PO2 but a reduced amount of hemoglobin available to carry oxygen?
Anemic hypoxia
What is the term sometimes used to describe Hypoxemia?
Hypoxic hypoxia
What is the primary effect of histotoxic hypoxia on tissues?
Inhibited oxygen utilization by tissue cells
How long does it take for the increase in circulating red blood cells to begin after ascent to high altitude?
In 2-3 days
What is the response to high altitude that leads to a decrease in erythropoietin secretion?
Increased ventilatory response
What is the term that is a more correct description of a condition with low oxygen levels in the tissues?
Hypoxia
What occurs in the tissues in response to hypoxia, besides the increase in circulating red blood cells?
Compensatory changes
Learn about the transport of oxygen and carbon dioxide in the lungs, including the changes in partial pressures and how they flow from higher to lower concentrations. Understand how this process allows for oxygenation of the blood in the pulmonary vasculature.
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