6. Think about the presence of hemoglobin in the catheter bag. What symptom would this loss of hemoglobin most strongly and immediately be linked to in the patient?

A. Loss of blood volume

B. Loss of heartbeat

C. Drop in blood oxygen saturation

D. Liver failure

When a neuron is stimulated, the area of the membrane at the point of stimulation becomes
more permeable to Na+. If a cell starts at resting potential (-70mv), and is then stimulated:
A. The membrane voltage will become < -70mV, because Na+ will move OUT of the cell.
B. The membrane voltage will become > -70mV, because Na+ will move OUT of the cell.
C. The membrane voltage will become < -70mV because Na+ will move INTO the cell.
D. The membrane voltage will become > -70mV because Na+ will move INTO the cell.

. At the peak of the action potential, the Na+ voltage-gated channels close, and K+ voltage-gated channels open in response to the positive membrane potential. In order to return the cell to its negative resting potential quickly:
A. K+ will diffuse along its concentration gradient INTO the cell.
B. K+ will diffuse along its concentration gradient OUT of the cell.
C. Na+ will reverse its direction of diffusion OUT of the cell.
D. The sodium-potassium pump will move Na+ OUT of the cell and K+ INTO the cell.
E. None of the above would return the cell to its negative resting potential quickly.

You experiment with higher concentrations of toxin and find cases when the cell could not
repolarize at all or, if it began to repolarize, it immediately depolarized again. This tells you that
the toxin:
A. Prevents voltage-gated K+ channels from opening.
B. Increases the speed that the Na+ ion channels open.
C. Prevents the Na+ ion channels from closing.
D. Makes the Na+ ion channels close too soon.
E. Doesn't affect the Na+ ion channels at all, it affects the sodium-potassium pump instead.

22. Why did Jim only take sips of water after the race? What is a serious side effect that could
happen if he drank as much as he wanted to?
A. His urinary volume might increase uncomfortably
B. Increased hydrolysis of blood glucose, leading to further depletion of ATP
C. Blood osmolarity becomes dangerously high
D. Blood osmolarity becomes dangerously low
23. After the race, Jim falls down and breaks his leg. His leg is in a cast for several months as the
bone heals. What is likely to happen to the skeletal muscle in Jim's broken leg during this time?
A. Muscle fiber hypertrophy
B. Denervation atrophy
C. Disuse atrophy
D. No change
In an alternate universe...
24. During the race, Jim's team rows past a corn field being sprayed with organophosphate
pesticide. Unaware of the danger, the team rows through the chemical fog, and inhales a large
amount of pesticide. What neurotransmitter will this affect?
A. Acetylcholine
B. Muscarine
C. Epinephrine
D. Dopamine
25. If the levels of pesticide are high enough to be lethal, what would be the primary cause of
death?
A. Asphyxiation due to airway constriction
B. Asphyxiation due to paralysis of diaphragm muscle
C. Cardiac arrest due to loss of stimulatory input from nervous system
D. Loss of oxygen binding to hemoglobin due to pesticide binding directly to hemoglobin