The Nervous System
Central nervous system (CNS) - Nervous system subdivision that is composed of the
brain and spinal cord.
Somatic nervous system - Subdivision of the PNS that controls voluntary activities
such as the activation of skeletal muscles.
Peripheral nervous system (PNS) - Nervous system subdivision that is composed of
the cranial nerves and spinal nerves.
Autonomic nervous system - Subdivision of the PNS that regulates the activity of the
cardiac muscle, smooth muscle, and glands. It is also called the involuntary nervous
system because it controls body activities automatically. It is very Important in
maintaining homeostasis for the body.
Neuroglia - Cells that support, insulate, and protect neurons. These cells are able to
divide and are usually involved in brain tumors.
Neurons - Cells that transmit electrical message from one area of the body to
another area.
Axon - End of neuron that releases neurotransmitters away from the cell body.
Dendrite - End of neuron that conducts electrical currents toward the cell body.
Myelin - White, fatty material that covers long nerve fibers, protecting and insulating
the fibers, as well as Increasing the speed of impulse transmission.
Cell body - Location of the nucleus in a neuron.
Schwann cells - Specialized cells that myelinate the fibers of neurons found in the
PNS.
Synapse - Junction or point of close contact between neurons.
Tract - Bundle of nerve processes inside the CNS.
Nodes of Ranvier - Gaps in the myelin sheath between schwann cells.
Ganglia - Collection of nerve cell bodies found outside the CNS.
Central nervous system (CNS) - Nervous system subdivision that is composed of the
brain and spinal cord.
Somatic nervous system - Subdivision of the PNS that controls voluntary activities
such as the activation of skeletal muscles.
Peripheral nervous system (PNS) - Nervous system subdivision that is composed of
the cranial nerves and spinal nerves.
Autonomic nervous system - Subdivision of the PNS that regulates the activity of the
cardiac muscle, smooth muscle, and glands. It is also called the involuntary nervous
system because it controls body activities automatically. It is very Important in
maintaining homeostasis for the body.
Neuroglia - Cells that support, insulate, and protect neurons. These cells are able to
divide and are usually involved in brain tumors.
Neurons - Cells that transmit electrical message from one area of the body to
another area.
Axon - End of neuron that releases neurotransmitters away from the cell body.
Dendrite - End of neuron that conducts electrical currents toward the cell body.
Myelin - White, fatty material that covers long nerve fibers, protecting and insulating
the fibers, as well as Increasing the speed of impulse transmission.
Cell body - Location of the nucleus in a neuron.
Schwann cells - Specialized cells that myelinate the fibers of neurons found in the
PNS.
Synapse - Junction or point of close contact between neurons.
Tract - Bundle of nerve processes inside the CNS.
Nodes of Ranvier - Gaps in the myelin sheath between schwann cells.
Ganglia - Collection of nerve cell bodies found outside the CNS.
