Double Bohr effect (Oxygen curves for maternal and foetal Hb move apart in opposite directions) occurs in

Correct Answer: C

Rationale: Rationale: 1. In the placenta, maternal and fetal blood circulations are in close proximity. 2. Maternal Hb releases oxygen to fetal Hb due to the lower affinity of fetal Hb for oxygen. 3. This double Bohr effect causes the oxygen dissociation curves of maternal and fetal Hb to move apart. 4. This occurs specifically in the placenta where both maternal and fetal circulations operate. Summary: A. Incorrect. Double Bohr effect doesn't occur solely in fetal circulation. B. Incorrect. Double Bohr effect doesn't occur solely in maternal circulation. C. Correct. Placenta facilitates the exchange between maternal and fetal blood causing the double Bohr effect. D. Incorrect. Double Bohr effect is not related to the uterine wall.

Correct Answer: C

Rationale: The correct answer is C: Biot's respiration. Biot's respiration is characterized by regular breathing interrupted by periods of apnea. In this scenario, the nurse observed normal breaths followed by a 20-second episode of apnea, which aligns with Biot's respiration. It is crucial to document this finding accurately to ensure appropriate care. Incorrect answers: A: Eupnea refers to normal breathing without any interruptions or irregularities. The presence of apnea in the scenario rules out eupnea. B: Apnea would be an incomplete assessment as it does not capture the alternating pattern of normal breaths and apnea observed in Biot's respiration. D: Cheyne-Stokes breathing involves a cyclical pattern of gradually increasing and decreasing breathing rates, which is not evident in the scenario described.

Correct Answer: A

Rationale: Natural killer (NK) cells are involved in innate immunity as they are able to directly kill virus-infected cells and tumor cells without prior sensitization. They are part of the body's first line of defense against infections. Plasma cells, CD8 T cells, and B memory cells are all part of adaptive immunity, which involves a specific response to pathogens and requires prior exposure. Therefore, they are not involved in innate immunity.

Correct Answer: C

Rationale: The correct answer is C: P outside < P inside. This is because pressure decreases as altitude increases. At label '8', the pressure outside the object (presumably at a higher altitude) is lower than the pressure inside the object. This is due to the decrease in air pressure with increasing altitude. Choice A is incorrect because at higher altitudes, the pressure outside is lower than inside. Choice B is incorrect as it suggests the opposite relationship. Choice D is incorrect as it does not accurately describe the relationship between the pressures at label '8'.

Correct Answer: C

Rationale: The correct answer is C (75 percent) because under quiet conditions, the venous blood returning to the heart still contains a significant amount of oxygen due to the efficient extraction of oxygen by tissues. This oxygen extraction process typically leaves around 25 percent of oxygen in the venous blood, which is then returned to the heart. Choices A (25 percent), B (50 percent), and D (90 percent) are incorrect because they do not accurately reflect the amount of oxygen retained in the blood under quiet conditions. Option A (25 percent) is the amount typically extracted by tissues, so it cannot be the correct answer. Option B (50 percent) is too high, as more oxygen is extracted by tissues. Option D (90 percent) is also too high, as it overestimates the amount of oxygen retained in venous blood.