Neurons Notes

The structural units of the nervous system are __________.

Neurons

The __________ is the biosynthetic centre of the neuron, where proteins, membranes, and chemicals are synthesized.

Cell body (perikaryon or soma)

In the CNS, clusters of neuron cell bodies are known as __________.

Nuclei

In the PNS, clusters of neuron cell bodies are referred to as __________.

Ganglia

Bundles of neuron processes in the CNS are called __________.

Tracts

Bundles of neuron processes in the PNS are called __________.

Nerves

Dendrites convey incoming messages toward the cell body as ___________ potentials.

Graded

The axon is the conducting region of the neuron that can generate nerve impulses called ____________ potentials.

Action

When axon terminals receive an action potential, they release ____________ that either excite or inhibit other neurons or effector cells.

Neurotransmitters

Anterograde movement refers to the transport of materials __________ the cell body.

Away from

Retrograde movement refers to the transport of materials __________ the cell body.

Towards

Multipolar neurons have __________ or more processes.

Three

Bipolar neurons have __________ axon and __________ dendrite.

One; one

Unipolar neurons have a single __________-shaped process.

T

__________ neurons, or afferent neurons, conduct impulses toward the CNS from receptors.

Sensory

__________ neurons, or efferent neurons, conduct impulses from the CNS to effectors.

Motor

__________ conduct impulses between sensory and motor neurons, and are also called association neurons.

Interneurons

A __________ is a specialized cell that transmits nerve impulses.

Neuron

The __________ receives signals from other neurons and conducts them toward the cell body.

Dendrite

The __________ transmits impulses away from the cell body to other neurons or muscles.

Axon

The __________ is the protective covering of the axon that facilitates faster impulse conduction.

Myelin sheath

A __________ is a collection of nerve fibers in the peripheral nervous system (PNS).

Nerve

A __________ is a collection of nerve fibers in the central nervous system (CNS).

Tract

A __________ is a cluster of neuron cell bodies in the CNS.

Nucleus

A __________ is a cluster of neuron cell bodies in the PNS.

Ganglion

Neurons can be classified by structure into __________, __________, and __________ types.

Multipolar; bipolar; unipolar

Functionally, neurons are classified as __________, __________, and __________ neurons based on their role in the nervous system.

Sensory; motor; interneurons