Nerve Quiz (1)

The main extracellular cation is:

• Sodium

• Magnesium

• Calcium

• Potassium

Sodium-potassium pump

• Is an example of active transport.

• Pumps 3 Na+ ion out of the nerve fiber and 2 K* ions into the nerve fiber

• Is the only cause of resting membrane potential.

Voltage-gated channels are characterized by:

• They are non-gated

• They open or close by change in the membrane potential

• They open when a hormone or neurotransmitter binds to the receptor

The myelinated nerve fiber has an outer layer of:

• Nerve cells

• Schwann cells & myelin sheath

• Plasma cells

• Epithelial cells

The cause of resting membrane potential is:

• Equal distribution of ions inside & outside the cell

• Unequal distribution of ions inside & outside the cell

• Na+/Mg++ pump

All the following statements are correct, EXCEPT

• The selective permeability of the membrane is responsible for the resting membrane potential

• The Na+-K+ pump pumps Na+ into the nerve fiber.

• The Na+-K+ pump requires energy which is supplied by ATP

The resting membrane potential of a nerve fiber:

• Includes all the changes in membrane potential during conduction of the nerve impulse.

• Is the potential difference between the inside and outside of the resting membrane.

• Is always around zero,

• Is due to the presence of negative ions on the outer surface of the membrane in relation to its inner surface