Neuroscience Practice Questions

In most neurons, the cell body represents what percent of the cell's total volume? a. 10% b. 20% c. 40% d. 5%

a. 10%

The average concentration of Na+ in the intracellular space is: a. 15.0 mmol/L b. 150.0 mmol/L c. 5.0 mmol/L d. 100.0 mol/L

a. 15.0 mmol/L

The RMP of neurons is determined primarily by: a. Non-gated K+ channels b. Gated K+ channels c. Both of the above d. Gated Na+ channels e. Non-gated Na+ channels

a. Non-gated K+

The motor molecule responsible for fast anterograde axonal transport is: a. myosin b. kinesin c. action d. dynein e. tropomyosin

b. kinesin

If two action potentials, A and B, have the same height, but B has a lower RMP, what is different about B? a. a lower conc. of Na+ ions b. lower conc. of K+ ions c. higher conc. of Na+ ions d. a and b e. b and c

b. lower K+

If the permeability of a resting (non-active) nerve cell to potassium ions is increased while the permeability of the cell to sodium ions remains constant (unchanged from that normally at rest). The resting membrane potential will: a. move away from zero (depolarize: become more -) b. move toward zero (hyperpolarize: become more +) c. be unaffected

b. move toward zero

Nerve stimulation test reveal a general reduction in conduction velocity along several different peripheral nerves consistent with segmental demyelination. The condition(s) could be: a. Multiple Sclerosis b. Lambert-Eaton Myasthenic Syndrome c. Guillain-Barre Syndrome d. a and b e. b and c

c. Guillain-Barre

Guillain-Barre syndrome and multiple sclerosis are 2 common disorders that associated with demyelination in the PNS ad CNS, respectively. Functional recovery can occur in both disorders by what mechanism? a. Migration of electric gated sodium channels in PNS and CNS b. Remyelination in PNS and migration of electric gated sodium channels in CNS c. Remyelination by Shwann cells in PNS and by oligodendrocytes in CNS d. Migration of electrically gated sodium channels in PNS and remyelination in CNS

c. Remyelination in PNS and migration of electrically gated sodium channels in CNS

The resting membrane potential of glial cells is: a. slightly more positive than eq. potential of K+ b. slightly more negative than eq. potential of K+ c. equal to that of the eq. potential of K+ d. slightly more positive than the eq. potential of Na+

c. equal to

What functional type of neuron is the most prevalent in the vertebrate nervous system? a. afferent and efferent neurons b. glial cells c. interneurons d. Renshaw cells

c. interneurons

Somatic efferent (motor neurons) fibers are classified as: a. unipolar cells b. bipolar cells c. multipolar cells d. pseudo-unipolar cells

c. multipolar cells

Microtubules are the essential stationary tract used for what type of axonal transport? a. slow axonal transport b. fast anterograde axonal transport c. fast retrograde transport d. all of the above e. b and c

e. fast anterograde and fast retrograde

Astrocytes serve the following functions with the exception of: a. nutritive function b. buffering function by taking up certain neurotransmitters from the synaptic area c. act as scavengers and remove neuronal debris d. buffering function by taking up excess potassium released during high activity e. none of the above since all are functions of astrocytes

e. none- all functions of astrocytes

How are local and action potentials different?

local potential are graded-they summate; APs are all or nothing and have voltage gated channels

Explain the after-polarization of in terms of electric-gated channels dynamics:

the membrane is more permeable to K+ than at rest -voltage gated and non gated are open so more leaves the cell

An action potential with an after-hyperpolarization is from an axon that is:

unmyelinated