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The ability to respond to stimuli and convert them into nerve impulses


the ability to transmit an impulse

Resting membrane potential

Difference in electrical charge across the plasma membrane. The membrane would be POLARIZED.

Sodium Potassium Pumps

How does the membrane maintain the difference in electrical charge established by diffusion of ions?

-70 mv

What is the resting membrane potential of a frog?

-40mv and -90mv

What is the resting membrane potential in a human?

Threshold Stimulus

The amt of stimulus needed to create an action potential. NA+ rushes into the cell increasing the number of positive ions inside the cell and changing the membrane polarity


The interior surface fo the membrane becomes less negative and the exterior surface becomes less positive


K+ moves out of the cell causing the membrane potential to move in a negative direction.


The membrane has become more negative than resting potential. Until the channels close.

Absolute Refractory Period

What period is it when the sodium ion channels are open, the membrane is totally insensitive to additional stimuli, regardless of the force of the stimulus?

Relative Refractory period

What period is it during repolarization, the membrane may be stimulated if a very strong stimulus is used?

Nerve impulse

Another name for the action potential in neurons.

Compound nerve action potential

The cumulation of action potential of all neurons in a nerve

deep pressure, cold temperature

Name a couple of physical factors that can inhibit a nerve impulse.


What toxin blocks synaptic transmission by preventing the flow of neural impulses from neuron to neuron?

Conduction Velocity

What is the name of the velocity of the action potential along a neural membrane?

larger the nerve the faster the conduction velocity, myelinated nerves are faster than unmyelinated nerves

What is the relationship between myelination and size and conduction velocity?


Form the supportive framework for the nervous tissue; contact and stimulate blood capillaries; convert blood glucose; secret proteins; regulate chemical composition of tissue fluid

Microglial Cells

Phagocytize and destroy microorganisms, foreign matter, and dead nervous tissue

Ependymal Cells

Line cavities of the brain and spinal cord; secrete and circulate cerebrospinal fluid


Form the myelin in the brain and spinal cord

Schwann Cells

the PNS glial cell that forms myelin

Satellite Cells

the PNS glial cell that surrounds the dorsal root ganglion neurons

Afferent Neurons

carry signals toward the CNS from the body periphery; sensory neurons

CNS - Central Nervous System

the brain and spinal cord collectively

Efferent Neuron

a neuron that conducts impulses away form the CNS to muscles and glands; motor neurons


collection of nerve cell bodies found outside the CNS


neuron serving as part of the conduction pathway between sensory and motor neurons; association neurons


specialized supporting cells in the CNS


a chemical released at the distal end of an axon that stimulates an adjacent cell; found in the synaptic vesicles of the axon terminal; initiates electrical current from one neuron to the next by diffusing across the synaptic cleft


a cordlike organ of the PNS composed of multiple nerve fibers ensheathed in connective tissue


a bundle of nerve processes

PNS - Peripheral Nervous System

Ganglia and spinal and cranial nerves


junction or point of close contact between neurons


impulse generator and transmitter

Axon Terminal

secretes neurotransmitters

Axon Hillock

region of the cell body from which the axon generates


receptive region of a neuron

Myelin Sheath

insulates the nerve fibers


may be involved in the transport of substances within the neuron

Neuronal Cell Body

site of the nucleus and most important metabolic area

Nissl Bodies

essentially rough endoplasmic reticulum, important metabolically

Multipolar Neuron

one axon and multiple dendrites; efferent neurons and interneurons are multipolar

Bipolar Neuron

one axon and one dendrite

Unipolar Neuron

one single process leading away from the soma; afferent neurons are unipolar


surrounds each nerve fiber


binds groups of fibers together to form bundles


binds all of the fascicles together

Mixed Nerve

nerves carrying both sensory and motor fibers

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