All the following statements regarding the glial cells are correct except:
1. They are rare when compared to neurons
2. They can respond to injury
3. They function in myelin sheath synthesis
4. They help in regulation of neuronal environment

In a single-ion system, reversal potential is synonymous with equilibrium potential; their numerical values are identical, and it:

1. Is a function of the concentration of that ion on the extracellular side of the membrane

2. Is a function of the concentration of that ion on the intracellular side of the membrane

3. Is the potential at which there is no movement of that ion across the membrane due to electrochemical forces

4. Is the potential at which there is equal movement of that ion into and out of the cell across the membrane due to electrochemical forces

The resting membrane potential is first established because of:
1. the movement of potassium ions down their electrical gradient through leak channels
2. the opening of voltage-gated sodium channels
3. the action of the Na+/K+ ATPase pump which transports positive ions in unequal numbers
4. the movement of sodium ions against their concentration gradient through leak channels

What is true for the events that occur during the generation of an action potential?
1. Potassium channels in the membrane open in response to depolarization
2. Sodium channels in the membrane open in response to neurotransmitter released from the adjacent membrane
3. The increase in sodium permeability in the membrane is an example of positive feedback
4. The movement of sodium into the neuron causes the cell to hyperpolarize

Threshold stimuli are those that are strong enough to:
1. Hyperpolarize the neuron membrane
2. Cause a net flux of negatively charged ions from inside to outside the cell
3. Cause a net flux of positively charged ions from outside to inside the cell
4. Close calcium channels to retain them in the cell

The period of time during which a second action potential cannot be initiated, no matter how large the applied stimulus is the absolute refractory period. Which statement is true for this period?

1. Potassium channels are open and the membrane is hyperpolarized
2. It immediately follows the relative refractory period
3. It allows an action potential to proceed in two directions along the length of an axon
4. It occurs when the sodium channels are open

All the following statements with respect to the propagation of action potentials are correct except:
1. Saltatory conduction occurs in myelinated nerve fibers
2. During conduction of an action potential, current flows from the active area of the membrane to the adjacent inactive area, thereby decreasing the potential in the inactive area to the threshold
3. Action potential propagation is faster in myelinated fibers than in unmyelinated ones
4. Action potential propagation is faster for strong stimuli than for weaker stimuli

An Inhibitory Post-Synaptic Potential:
1. causes depolarization
2. is caused by an increase in the permeability of the postsynaptic membrane to potassium or chloride ions
3. causes repolarization
4. is caused by an increase in the permeability of the postsynaptic membrane to sodium ions

Common inhibitory neurotrnasmitters in brain and spinal cord are:

1. Glutamate
2. GABA (gamma-amino-butyric aci4.
3. Glutamate and glycine
4. GABA (gamma-amino-butyric acid and glycine

The blood–brain barrier (BBB) separates the circulating blood from the brain and extracellular fluid in the central nervous system (CNS) and:

1. Functions to control the exchange of substances between blood and the extracellular fluid in the CNS

2. Is comprised of the cells that line the largest blood vessels in the brain

3. Is comprised of the cells that line the ventricles of the brain

4. Prevents diffusion of lipid soluble molecules from the blood to the brain