Nokea
Most of the oxygen transported by the blood is
- A. dissolved in plasma
- B. bound to hemoglobin
- C. in ionic form as solute in the plasma
- D. bound to the same protein as carbon dioxide
Correct Answer: B
Rationale: The correct answer is B: bound to hemoglobin. This is because hemoglobin is the protein in red blood cells that carries oxygen from the lungs to tissues throughout the body. Oxygen binds to the iron atoms in hemoglobin, forming oxyhemoglobin. This accounts for the majority of oxygen transport in the blood.
A: Dissolved in plasma is incorrect as only a small fraction of oxygen is carried this way.
C: In ionic form as a solute in plasma is incorrect as oxygen is not typically found in ionic form in the blood.
D: Bound to the same protein as carbon dioxide is incorrect as oxygen binds to hemoglobin, while carbon dioxide primarily binds to different proteins such as carbonic anhydrase.
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Cloacal respiration is found in
- A. Snake
- B. Turtle and Tortoise
- C. Crocodile
- D. Frog
Correct Answer: B
Rationale: Cloacal respiration is found in turtles and tortoises. These reptiles can absorb oxygen through their cloaca, a multi-functional opening used for excretion and reproduction. Turtles and tortoises lack specialized respiratory organs like lungs, and thus utilize cloacal respiration as an additional means of obtaining oxygen. Snakes (Option A) primarily rely on lung respiration. Crocodiles (Option C) have well-developed lungs for breathing. Frogs (Option D) respire through their skin and lungs but do not utilize cloacal respiration like turtles and tortoises. Therefore, the correct answer is B, as it is the only species listed that exhibits cloacal respiration.
Foetal hemoglobin has great affinity than adult hemoglobin because
- A. It binds 2,3 DPG less avidity by Gamma polypeptide chain than HbA
- B. Its concentration is very high
- C. Foetal blood gets oxygen from the mother
- D. Its polypetide chains bind very fast with Oxygen
Correct Answer: A
Rationale: The correct answer is A because 2,3 DPG binds less avidly to the Gamma polypeptide chain in foetal hemoglobin, resulting in a higher affinity for oxygen. This is due to structural differences between foetal and adult hemoglobin. Choice B is incorrect as high concentration alone does not determine affinity. Choice C is incorrect as the source of oxygen does not affect hemoglobin's affinity. Choice D is incorrect as the speed of oxygen binding does not necessarily correlate with affinity.
For a patient with advanced chronic obstructive pulmonary disease (COPD), which nursing action best promotes adequate gas exchange?
- A. Encouraging the patient to drink three glasses of fluid daily.
- B. Keeping the patient in semi-Fowler's position.
- C. Using a high-flow venturi mask to deliver oxygen as prescribed.
- D. Administering a sedative, as prescribed.
Correct Answer: C
Rationale: The correct answer is C: Using a high-flow venturi mask to deliver oxygen as prescribed. This is the best option as it directly addresses the issue of promoting adequate gas exchange in a patient with advanced COPD. The high-flow venturi mask delivers oxygen at a precise concentration, ensuring optimal oxygenation.
Encouraging the patient to drink fluids (A) is important for overall health but does not directly address gas exchange. Keeping the patient in semi-Fowler's position (B) can help with breathing but is not as effective as providing supplemental oxygen. Administering a sedative (D) can further depress the respiratory system and worsen gas exchange, making it an inappropriate choice.
Blocking afferent action potentials from the chemoreceptors in the carotid and aortic bodies would interfere with the brain's ability to regulate breathing in response to
- A. changes in PCO2
- B. changes in PCO2
- C. changes in pH
- D. changes in blood pressure
Correct Answer: B
Rationale: The correct answer is B: changes in PCO2. Chemoreceptors in the carotid and aortic bodies detect levels of oxygen, carbon dioxide, and pH in the blood. Blocking afferent action potentials from these chemoreceptors would specifically interfere with detecting changes in PCO2, as these receptors primarily respond to alterations in CO2 levels. This interference would disrupt the brain's ability to regulate breathing in response to changes in PCO2, leading to potential respiratory problems. Choices A and C are incorrect because chemoreceptors primarily respond to CO2 levels, not O2 or pH. Choice D is incorrect because changes in blood pressure are primarily detected by baroreceptors, not chemoreceptors in the carotid and aortic bodies.
Regarding oxygen transport
- A. The predominant way oxygen is transported in the blood is as dissolved oxygen
- B. 1 gram of pure Hb can combine with 1.34 - 1.39 ml of oxygen
- C. An anaemic patient has a lowered arterial pO2 because the Hb is low
- D. CO2 is 200 times more soluble than oxygen
Correct Answer: B
Rationale: The correct answer is B: 1 gram of pure Hb can combine with 1.34 - 1.39 ml of oxygen. This is correct because each gram of hemoglobin can bind with approximately 1.34 - 1.39 ml of oxygen, facilitating efficient oxygen transport in the blood.
A is incorrect because while a small amount of oxygen is transported as dissolved oxygen, the majority is transported bound to hemoglobin.
C is incorrect because arterial pO2 reflects the oxygen content in the blood, not just the hemoglobin levels.
D is incorrect because CO2 is actually 20 times more soluble than oxygen, not 200 times.