The cell membranes of photoreceptors contain sodium and calcium channels that are normally ___.
a. open
b. closed
c. depolarized
d. refractory
Question 2
High levels of leptin and insulin in obese individuals do not inhibit eating because they:
a. Seem to be less responsive to these than normal-weight people
b. Have damage to the hypothalamus
c. Have abnormally low levels of neuropeptide Y
d. Do inhibit eating, but glucose levels must be much higher