Test Bank for Chapter 04: Neuronal Function and Structure

RNA

is synthesized in the nucleolus.

Major classes of molecules in neuronal cells

do not include sugars.

Messenger RNA

carries a code that can be directly read by the ribosome mechanism.

Proteins

can be secreted by all of the above.

Neurons classification

are classified according to their shape.

Axons of neurons

vary greatly in diameter.

Point of contact from one axon to another neuron

is the terminal bouton.

Concentration gradient

protein ions in the intracellular fluid can permeate the neural cell membrane.

Channels in the cell membrane

may be voltage- or chemically gated.

An example of an anion

is Chloride.

Found in high concentration outside the cell

is Sodium.

Relative amount of voltage in an electrical field

is the definition of potential.

Allow some ions to move against their gradient

are Sodium-potassium pumps.

During resting potential

the ionic difference across the membrane is at a steady state.

Adequate stimulus

An adequate stimulus to a neuron may act to depolarize the cell.

Action potential characteristics

All of the following are characteristic of an action potential EXCEPT neural information is signaled by the amplitude of the action potential.

Depolarization

Depolarization occurs when the difference in potential across the cell membrane is 55 mV.

Action potential propagation

A(n) action potential is propagated from the axon hillock to the terminal bouton.

Graded potential

A(n) graded potential is propagated from the cell membrane at the point of synapse with another neuron.

Action potentials development

Action potentials develop at the nodes of Ranvier.

Myelin

Myelin prevents leakage of current from the axon into the extracellular fluid.

Neural impulse transmission

A neural impulse is transmitted across the synaptic cleft primarily through chemical means.

Electrical synapse

An electrical synapse occurs at gap junctions between dendrites.

Synapse components

Which of the following is NOT a component of the synapse? The axon hillock.

Synaptic vesicles release

At the synapse, the action potential causes voltage-gated channels to release calcium ions before the synaptic vesicles release neurotransmitters.

Neurotransmitter function

A neurotransmitter serves to open ionic channels in the postsynaptic membrane.

Neurotransmitter inactivation

A neurotransmitter must be inactivated after it is released from the synaptic vesicles.

Neurotransmitter storage

A neurotransmitter is stored in the postsynaptic membrane.

Neurotransmitter types

A neurotransmitter can be excitatory, not inhibitory.

Neurotransmitter options

Both A and D.

Major inhibitory neurotransmitter

GABA.

Neurotransmitter deficiency in Parkinson's disease

Dopamine.

Condition resulting from inability to transmit acetylcholine

Myasthenia gravis.

Term describing branching system of neurons

Divergence.

Primary neuronal loss

Occurs in the vicinity of the neurologic injury.

Regeneration of neurons in adults

In the PNS through axonal sprouting if the nerve is not severed.

Difference in degeneration of CNS vs PNS

Groups of neurons in the vicinity of a lesion are more likely to die in the CNS than PNS.

Spontaneous regeneration of CNS neurons

Deterred by glial scar tissue development after injury.

Direction of neural impulse travel

From proximal to distal along the dendrites to the soma of neurons.

Neural impulse conduction speed based on axon diameter

A neuron with an axon of small diameter will conduct neural impulses faster than a neuron with an axon of a large diameter.

Neural membrane pump operation

The pumps in the neural membrane open to both sides of the neuron simultaneously.

Energy consumption by the nervous system

Most of the energy consumed by the nervous system is used for the movement of ions.

Graded potential and action potential

A graded potential results in the generation of an action potential.

Wallerian degeneration

Occurs with damage to the distal portion of the axon causing the myelin sheath to pull away and the axon to swell.

Monoclonal antibodies in MS treatment

Antibodies derived from cloning unique red blood cells.

Synaptic divergence in the cerebellum

An abundance of synaptic divergence can be found in the cerebellum.