Brain & Spinal Cord Anatomical Terms/Functions

Central Nervous System (CNS)

Consists of the brain and spinal cord; responsible for integration.

Peripheral Nervous System (PNS)

Consists of sensory and motor neurons; transmits signals to/from CNS.

Sensory (Afferent) Function

Detects internal or external stimuli; carries signals TOWARD the CNS.

Integrative Function

Processes and analyzes incoming sensory information.

Motor (Efferent) Function

Carries commands AWAY from CNS to effectors (muscles and glands).

Dendrites

Input region of a neuron; receives incoming signals.

Cell Body (Soma)

Integrative region of a neuron; contains the nucleus and organelles.

Axon

Conduction zone of a neuron; carries action potentials away from cell body.

Axon Hillock

Cone

Trigger Zone

Junction of axon hillock and initial segment where action potentials originate.

Axon Terminal

Distal branches of an axon that end in synaptic end bulbs.

Synaptic End Bulb

Expanded end of axon terminal containing neurotransmitters in vesicles.

Interneuron

Neurons located entirely within CNS that connect sensory and motor pathways.

Astrocytes

CNS glial cells that form blood

Oligodendrocytes

CNS glial cells that form myelin sheaths around axons.

Microglia

Smallest CNS glial cells; act as phagocytes/immune defense clearing debris.

Ependymal Cells

CNS glial cells lining ventricles and central canal; produce and circulate CSF.

Schwann Cells

PNS glial cells that form myelin sheaths and assist in nerve repair.

Satellite Cells

PNS glial cells that support neuron cell bodies in dorsal root ganglia.

Dura Mater

Outermost, tough connective tissue layer of meninges.

Arachnoid Mater

Delicate, web

Pia Mater

Innermost, thin meningeal layer tightly adhering to brain and spinal cord surface.

Choroid Plexus

Specialized vascular network that secretes Cerebrospinal Fluid (CSF).

Dorsal (Posterior) Root

Nerve root carrying SENSORY impulses into the spinal cord.

Dorsal Root Ganglion

Swelling on dorsal root containing cell bodies of sensory neurons.

Ventral (Anterior) Root

Nerve root carrying MOTOR impulses away from spinal cord to effectors.

Dorsal Gray Horn

Area of spinal cord gray matter processing incoming sensory information.

Ventral Gray Horn

Area of spinal cord gray matter containing somatic motor neuron cell bodies.

Lateral Gray Horn

Area of spinal cord gray matter containing autonomic motor neuron cell bodies.

Ascending Tracts

Axon bundles in spinal cord white matter carrying sensory signals UP to brain.

Descending Tracts

Axon bundles in spinal cord white matter carrying motor signals DOWN from brain.

31

Number of pairs of spinal nerves connected to the spinal cord.

Sympathetic Nervous System

Autonomic branch responsible for "fight or flight" responses.

Parasympathetic Nervous System

Autonomic branch responsible for "rest and digest" activities.

SLUDD

Mnemonic for parasympathetic functions: Salivation, Lacrimation, Urination, Defecation, Digestion.