Question 1

The dissociation curve of CO₂ in blood is: A)Linear and directly related to partial pressure of carbon dioxide (Pco₂). B)Linear and not related to Pco₂. C)Not linear D)Linear and directly related to partial pressure of oxygen (Po₂). E)S-shaped and directly related to Pco₂.

Accepted Answer

A

Question 2

The ability of CO₂ to alter the affinity of hemoglobin for O₂,which enhances O₂ delivery to tissues and O₂ uptake in the lungs,is referred to as: A)Chloride shift B)Haldane's effect C)Bohr's effect D)Hamburger's phenomenon E)Graham's effect

Accepted Answer

This phenomenon is referred to as Bohr's effect, which describes how the affinity of hemoglobin for oxygen is affected by pH and CO2 levels. The presence of CO2, which combines with water to form carbonic acid, lowers the pH, causing hemoglobin to release more oxygen to tissues in need. This increases O₂ delivery and uptake, and is an important factor in regulating breathing during exercise and at high altitudes.

Question 3

A 48-year-old man presents with a low Pao₂,low oxygen content in arterial blood (Cao₂),low amount of O₂ delivered,and a normal amount of O₂ utilized.He is probably suffering from what type of hypoxia?

A)Circulatory
B)Hypoxic
C)Anemic
D)Histotoxic

Accepted Answer

B

Question 4

A 10-year-old girl with primary pulmonary hypertension is receiving nitric oxide therapy for its vasodilatation properties.She presents with a deficiency in oxygen-carrying capacity with the hemoglobin iron molecule in the ferric acid state and a methemoglobin level of 10%.She probably has a condition known as:

A)Sickle cell disease.
B)Anemia.
C)Methemoglobinemia.
D)Hypoxic shock.
E)Restrictive lung disease.

Accepted Answer

The presence of methemoglobin (in which the iron in hemoglobin is in the ferric state and is unable to carry oxygen) suggests methemoglobinemia. Primary pulmonary hypertension may cause hypoxia, leading to the use of nitric oxide therapy for vasodilation. Sickle cell disease is a hemoglobinopathy with a different mechanism of pathology. Anemia refers to a low hemoglobin concentration without any specific indication of methemoglobinemia. Hypoxic shock and restrictive lung disease are not consistent with the presented information.

Question 5

A 62-year-old woman is admitted to the hospital with fever and pneumonia.How is her O₂ dissociation curve affected by her clinical status? A)A shift to the left B)A shift to the right C)No change D)A downward shift E)An upward shift

Accepted Answer

Clinical status such as fever and pneumonia can cause a decrease in pH of blood which leads to an increase in acidity. This increase in acidity causes a shift in the oxygen-hemoglobin dissociation curve to the right. This shift to the right means that the hemoglobin is less saturated with oxygen at any given partial pressure of oxygen.

Question 6

The predominant transport mechanism of CO₂ in blood is by: A)Dissolved CO₂. B)Carbamino protein complexes. C)Hemoglobin binding. D)HCO₃^- within red blood cells. E)Deoxyhemoglobin

Accepted Answer

CO₂ binds strongly to HCO₃^- within red blood cells, which is known as the carbamino effect. This mechanism is the predominant transport mechanism of CO₂ in blood.

Question 7

A 44-year-old man who has experienced trauma is given multiple blood transfusions because of severe blood loss.What influence would this treatment have on his O₂ dissociation curve? A)A shift to the left B)A shift to the right C)No change D)A downward shift E)An upward shift

Accepted Answer

Multiple blood transfusions can lead to a decrease in 2,3-BPG levels in stored blood, causing a leftward shift in the oxygen dissociation curve, which increases hemoglobin's affinity for oxygen.

Question 8

A 12-year-old girl of Hispanic descent enters the emergency department with severe pain on the left side of her abdomen.The family has recently immigrated to the United States.First attempts at pain relief with nonnarcotic drugs are unsuccessful.Opioids are needed to suppress the pain.Her laboratory results show that she is anemic and her parents reveal a history of chronic infections and a stroke.Genetic testing reveals that her hemoglobin gene has a single amino acid substitution of valine for glutamic acid.Her primary diagnosis is:

A)Blunt traumatic injury to the spleen.
B)Aneurysm.
C)Sickle cell disease.
D)Cystic fibrosis

Accepted Answer

The girl's symptoms, history of chronic infections and stroke, anemia, and genetic testing all suggest sickle cell disease, a disorder in which the hemoglobin protein has a valine substitution for glutamic acid, leading to abnormal blood cell shapes and potential blockages in blood vessels, causing severe pain as well as increased risk for infections and strokes. The other options are less likely to be the cause of her symptoms based on the given information.

Question 9

Pulmonary vascular resistance increases during hypoxia; how should it behave during exercise?&#10;A)Decreases&#10;B)Initially stays the same and then increases with time&#10;C)Increases&#10;D)Stays the same; not influenced

Accepted Answer

During exercise, pulmonary vascular resistance should decrease to allow for increased blood flow to the lungs and to meet the oxygen demand of the working muscles. Hypoxia refers to a state of low oxygen levels, and during this state, pulmonary vascular resistance increases as a compensatory mechanism to redirect blood flow to areas of the lungs that are better ventilated, thereby ensuring the efficient exchange of oxygen and carbon dioxide. However, during exercise, there is an overall increase in ventilation and oxygen uptake, thereby reducing the hypoxic stimulus and hence reducing pulmonary vascular resistance.

Question 10

Tissue hypoxia is caused by all of the following except:&#10;A)Anemia.&#10;B)Carbon monoxide poisoning.&#10;C)Cyanide poisoning.&#10;D)Shock.&#10;E)Pneumonia.

Accepted Answer

Pneumonia may affect lung function and oxygenation but it is not a direct cause of tissue hypoxia. Anemia, carbon monoxide poisoning, cyanide poisoning, and shock are all known causes of tissue hypoxia.

Deck 24: Oxygen and Carbon Dioxide Transport