Midterm1_F10_W

Question 1

There are 2
neurons that are identical EXCEPT in one neuron, the myelin between the nodes of Ranvier has been
removed (like in the diseases ALS or MS).

Action potential threshold is crossed later at the location of
the next node in the demylinated axon because

Answer 1

Lower rm (membrane resistance) causees more voltage attenuation in the next node and the threshold is crossed later

Question 2

T/F Gap junctions connect 2 neurons so that molecules can pass but ions can’t

Answer 2

F

Question 3

T/F Gap junctions have gates that open when the threshold is crossed selectively increasing Na+ permeability

Answer 3

F

Question 4

T/F Gap junctions have central pores that can open and close depending on the presence of chemicals

Answer 4

F

Question 5

Why is it important for the cell membrane to be thin?

Answer 5

Keeps capacitance manageably high and allows charge to attract/repel each other through the membrane

Question 6

At the overshoot peak of an AP, the chemical and electrical force on K+ drives K+ to the (inside/outside) of the cell

Answer 6

outside

Question 7

At the undershoot (lowest peak) of an AP, the net force on K+ drives K+ to the (inside/outside) of the cell

Answer 7

outside

Question 8

At the undershoot (lowest peak) of an AP, the net force on K+ drives K+ to the (inside/outside) of the cell

-Potassium leak channel
-Voltage gated potassium channel
-Sodium leak channel
-Voltage gated sodium channel
-Calcium leak channel
-Voltage gated calcium channel
-Chloride leak channel -Voltage gated chloride channel

Answer 8

VG K+ channel - voltage is positive which repels positive potassium to the outside