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Biology

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14. A previously well 18-year-old girl is admitted to the

UTH because of altered mental status. She does not respond to instructions and her arms are postured in a flexor position. Laboratory data reveal a serum sodium concentration of 125mmol/L. Her friends indicate that the patient had taken ecstasy at a party the night before in G-Greens area, and because she was extremely thirsty the next morning, she had consumed a lot of water in a short period of time. Assuming that the reduction in osmolarity is entirely due to water consumption that her initial weight was 60 kg, but 70kg on admission and that her initial osmolarity was 300 mOsm/L, which of the following is approximately how much water is in blood circulation and what condition is this?
A.       2.5 L - hyponatremia
B.       3.5 L - hyponatremia
C.       5 L - hypokalemia
D.       6 L - hypokalemia
E.        7 L - Hypocalcemia
16.      At equilibrium the concentrations of Cl- inside and outside a cell are 8 mmol/L and 120 mmol/L, respectively. The equilibrium potential for Cl- at 37C is calculated to be
A.       -4.07 mV
B.       +4.07 mV
C.       -71.7 mV
D.       +71.7 mV
E.        -91.5 mV
F.        +91.5 mV
18.      The after-hyperpolarization phase of the action potential is caused by
A.       An outward calcium current
B.       An inward chloride current
C.       An outward potassium current
D.       An outward sodium current
E.        An outward chloride current