Ovarian tumours | NEET Based MCQs

Ovarian tumours are commonly arise from 

A. Stroma
B. Surface epithelium
C. Germinal epithelium
D. Endodermal

The Answer is D. The A — a gradient is the partial pressure difference between the alveolar i and arterial oxygen tensions. The arterial blood gas tension has been measured. The alveolar oxygen tension must be calculated using the modified alveolar gas equation.

                                                            30 mmHg

P_AO₂ = 0.21 x (760—47) mmHg  -------------------

                                                                  0.8

P_AO₂ = 150 mmHg— 37.5 mmHg= 112.5 mmHg

(A — a) _oxygen gradient = 113 mmHg — 60 mmHg = 53 mmHg

The patient’s low arterial oxygen tension results from a decrease in diffusion capacity and V/Q abnormalities. The resulting hypoxemia will lead to an increase in red blood cell production and therefore an increase in hematocrit. The low oxygen will also cause an increase in pulmonary vascular resistance and therefore an increase in right atrial pressure. Hypoxemia will also lead to an increase in alveolar ventilation and a respiratory alkalosis, which will be compensated for by an increase in bicarbonate concentration.