Neuroscience: CNS, PNS, Neurons, and Spinal Cord Structure

What is the Central Nervous System (CNS)?

The part of the nervous system that includes the brain and spinal cord.

What is the Peripheral Nervous System (PNS)?

The part of the nervous system that includes all the nerves outside the CNS, connecting it to the rest of the body.

What is the sensory (afferent) division of the PNS?

The part of the PNS that transmits sensory information from receptors to the CNS.

What is the motor (efferent) division of the PNS?

The part of the PNS that carries signals from the CNS to muscles and glands.

What is the somatic nervous system?

The division of the motor PNS that controls voluntary movements of skeletal muscles.

What is the autonomic nervous system (ANS)?

The division of the motor PNS that regulates involuntary functions, such as heart rate and digestion.

What are the two divisions of the autonomic nervous system?

The sympathetic division and the parasympathetic division.

What are the basic components of a neuron?

The cell body, dendrites, and axon.

What is a nerve?

A bundle of axons in the PNS that transmits signals.

What is a ganglion?

A cluster of neuron cell bodies in the PNS.

What is a plexus?

A network of intersecting nerves.

What is a tract?

A bundle of axons in the CNS.

What are sensory (afferent) neurons?

Neurons that carry sensory information to the CNS.

What are motor (efferent) neurons?

Neurons that carry signals from the CNS to muscles or glands.

What are interneurons?

Neurons that connect sensory and motor neurons within the CNS.

What are oligodendrocytes?

Neuroglia cells in the CNS that form myelin sheaths around axons.

What are Schwann cells?

Neuroglia cells in the PNS that form myelin sheaths around axons.

What is myelination?

The process of forming a myelin sheath around a nerve fiber.

What are the three layers of the meninges?

Dura mater, arachnoid mater, and pia mater.

What is the epidural space?

The space between the dura mater and the vertebral wall that contains blood vessels and fat.

What is the subarachnoid space?

The space between the arachnoid mater and pia mater that contains cerebrospinal fluid.

What is white matter?

Regions of the CNS that contain myelinated axons.

What is gray matter?

Regions of the CNS that contain neuron cell bodies and unmyelinated axons.

What is the central canal?

The small channel in the center of the spinal cord that contains cerebrospinal fluid.

What is the dorsal (posterior) root?

The part of a spinal nerve that contains sensory axons.

What is the ventral (anterior) root?

The part of a spinal nerve that contains motor axons.

What is the brachial plexus?

A network of nerves that supplies the upper limb.

What is the phrenic nerve?

A nerve that originates from the cervical plexus and innervates the diaphragm.

What is the median nerve?

A nerve in the arm that innervates muscles in the forearm and hand.

What is the sciatic nerve?

The largest nerve in the body that branches into the tibial and common fibular nerves.