The Nervous System Review

____________ is a short period of time after an action potential when a threshold stimulus will NOT trigger another action potential.

• Threshold period
• Hyperpolarization
• Excitatory period
• Refractory period

What must happen within a neuron for it to reach its threshold in order to carry out an action potential?

• Sodium ions must diffuse outside of the cell causing the inside to become increasingly more negative.
• Sodium ions enter the cell via open channels in order to make the inside of the cell increasingly less negative.
• Potassium channels open to allow ions to move outside of the cell in order to make the cell increasingly more negative.
• Potassium ions must diffuse outside of the cell causing the inside to become increasingly more positive.

Multipolar neurons called __________ neurons send signals from the central nervous system to effectors, such as muscles and glands

• Sensory
• Motor
• Association

Narrow gaps in the myelin sheath between Schwann cells are called _____________.

• Neurilemma
• Myelinated Fibers
• Nodes of Ranvier
• Dendrites

The _________ transmits the impulse away from axon hillock of the cell body and may give off side branches.

• dendrite
• axon
• myelin sheath
• nodes of Ranvier

A junction between two neurons is called a _________.

• synapse
• synaptic knob
• receptor

If sufficient depolarization occurs, a ________ _________ is achieved as ion channels open. (Hint: -55 mV) At this point an action potential is reached.

The CNS is almost all ________.

• Multipolar
• Bipolar
• Unipolar

Which of the following in NOT a type of neuroglia?

• Astrocyte
• Oligodendrocyte
• Neuron
• Microglial cell

What maintains the resting potential of the neuron?

• Sodium channels only

• potassium channels only

• The Sodium-Potassium Pump

• Calcium channels only