Unit 1 (part 1): Structure of the Nervous System

Anterior (aka _____) refers to which direction?

Rostral; toward the front of the body.

Posterior (aka _____) refers to which direction?

Caudal; toward the back of the body.

Refers to the upper side of the body.

Dorsal.

Refers to a anatomical reference meaning ‘towards the belly’.

Ventral.

The invisible line running down the middle of the nervous system.

The midline.

Structures closer to the midline are _____; structures farthur away from the midline are _____.

Medial; lateral.

Ipsilateral

Refers to structures on the same side of the body.

Contralateral

Refers to structures on opposite sides of the body.

The plane of the section resulting from splitting the brain into equal right and left halves.

Midsagittal plane

Sections parallel to the midsagittal plane are in the:

Sagittal plane.

The anatomical plane that is parallel to the ground.

Horizontal plane.

The anatomical plane that is perpindicular to the ground.

Coronal plane.

Central nervous system (CNS) consists of:

The parts of the nervous system that are encased in bone: the brain and the spinal cord.

Rostral-most and largest part of the brain:

The cerebrum.

The cerebrum is split into two _____.

Cerebral hemispheres: the right receives sensory information from the left side of the body, and the left receives sensory information from the right side.

Structure attached to the brainstem at the pons and is an important movement control center.

The cerebellum.

Brainstem

Serves to relay information from the cerebrum to the spinal cord and cerebellum, and vice versa.

Spinal nerves

Nerves that emerge from the spinal cord (part of PNS) and transmit information between the central nervous system and the rest of the body.

Dorsal root

A bundle of sensory neuron axons that emerges from a spinal nerve and attaches to the dorsal side of the spinal cord. Dorsal root axons bring information into the spinal cord.

Ventral root

A bundle of motor neuron axons that emerges from the ventral spinal cord and joins sensory fibers to form a spinal nerve. Ventral root axons carry information away from the spinal cord.

Peripheral nervous system (PNS)

The parts of the nervous system other than the brain and spinal cord. The PNS includes all the spinal ganglia and nerves, cranial nerves III–XII, and the autonomic nervous system.

Somatic PNS

The part of the peripheral nervous system that innervates the skin, joints, and skeletal muscles.

Dorsal root ganglia

A collection of cell bodies of the sensory neurons that are part of the somatic PNS. There is one dorsal root ganglion for each spinal nerve.

Afferent

An axon coursing toward and innervating a given structure.

Efferent

An axon originating in and coursing away from a given structure.

Autonomic nervous system (ANS)

A system of central and peripheral nerves that innervates the internal organs, cardiovascular system, and glands; also called visceral PNS. The ANS consists of sympathetic, parasympathetic, and enteric divisions.

Cranial nerves

Twelve pairs of nerves that arise from each side of the brain stem, numbered from anterior to posterior. Cranial nerve I is actually the olfactory tract, and cranial nerve II is the optic nerve; both are parts of the central nervous system. Cranial nerves III–XII, which are in the peripheral nervous system, perform many diverse functions.

Meninges

Three membranes that cover the surface of the central nervous system: the dura mater, arachnoid membrane, and pia mater.

Dura mater

The outermost of the three meninges, the membranes that cover the surface of the central nervous system.

Arachnoid membrane

The middle of the three meninges, the three membranes that cover the surface of the central nervous system.

Pia mater

The innermost of the three meninges, the membranes that cover the surface of the central nervous system.

Cerebrospinal fluid (CSF)

In the central nervous system, the fluid produced by the choroid plexus that flows through the ventricular system to the subarachnoid space.

Ventricular system

The cerebrospinal fluid-filled spaces inside the brain, consisting of the lateral ventricles, third ventricle, cerebral aqueduct, and fourth ventricle