An age-related condition when the eye's lens doesn't change shape as easily as it once did [Presbyopia] is usually caused by:
1. decreasing the flexibility of the lens
2. an eyeball that is slightly too short
3. an eyeball that is slightly too long
4. a cornea with asymmetric curvature

Protein synthesis in neuron is carried out directly by:

The neuron in humans with many nerve fibers arising from its cell body and that carries impulses to the effectors would be called as:

All the following statements regarding nerve impulse conduction are correct except:
1. Myelinated neurons have a higher conduction velocity than unmyelinated neurons.
2. Nerve impulses occur in an all-or-none manner.
3. The neuron cannot be stimulated during the depolarization phase.
4. The strength of impulses carried along a single nerve fiber can vary with the strength of their stimulus.

Four cavities located within the brain that contain cerebral spinal fluid are known as:

The number of cranial nerves in humans is:

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

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