General Organization and Structure of the Nervous System

Comprehensive vocabulary flashcards covering the anatomical divisions, cellular components, protective layers, brain structures, spinal organization, and autonomic pathways of the nervous system.

Sensory function

The nervous system function that receives and inputs information from receptors toward the central nervous system via afferent pathways.

Integrative function

The processing and analysis of information carried out in the somas of neurons, forming grey matter where nuclei are located in the CNS.

Effector function

The motor output function that carries response commands from the central nervous system to target organs or tissues via axons along efferent pathways.

Central nervous system (CNS)

The division located medially in the body and protected by the skull and vertebrae, consisting of the brain, medulla, and spinal cord.

Peripheral nervous system (PNS)

The division located lateral to the central nervous system that is not protected by bones, composed of cranial and spinal nerves, ganglia, and sensory endings.

Somatic nervous system

The voluntary motor division of the PNS that innervates skeletal muscle targets and produces only excitatory stimuli.

Autonomic nervous system

The involuntary motor division of the PNS that controls smooth muscle, cardiac muscle, glands, and adipose tissue using excitatory or inhibitory stimuli.

Glial cells (Neuroglia)

Supporting cells that outnumber neurons and provide physical and metabolic support, nutrition, and protection throughout the nervous system.

Satellite cells

Glial cells of the peripheral nervous system that provide physical support and shape the ganglia.

Schwann cells

Glial cells of the peripheral nervous system responsible for myelin production around axons to speed up nerve impulses.

Oligodendrocytes

Glial cells of the central nervous system responsible for forming myelin sheaths around axons.

Astrocytes

Central nervous system glial cells whose cytoplasmic expansions act as intermediates between blood vessels and neurons to regulate substance transport.

Microglia

Resident immune cells of the central nervous system that defend neural tissue against infectious agents.

Ependymal cells

Central nervous system glial cells responsible for isolating the nervous system from the fluid compartments of the CNS.

Nuclei

Groups of neuron cell bodies (somas) sharing the same function located within the grey matter of the central nervous system.

Ganglia

Aggregations of neuron cell bodies (somas) located in the peripheral nervous system.

Tracts

Groups of axons sharing the same origin and destination found within the white matter of the central nervous system.

Nerves

Bundles of axons in the peripheral nervous system that transmit afferent sensory information and efferent motor responses.

Meninges

Three connective tissue membranes (dura mater, arachnoid, and pia mater) protecting central nervous tissue from direct contact with bone.

Dura mater

The outermost, highly resistant, fibrous layer of the meninges.

Epidural space

The anatomical space situated between the bone and dura mater containing fat and connective tissue.

Subdural space

The space located between the dura mater and arachnoid containing serous fluid for lubrication.

Subarachnoid space

The space located between the arachnoid and pia mater through which cerebrospinal fluid circulates.

Pia mater

The innermost and thinnest meningeal layer that directly adheres to and coats the surface of central nervous tissue.

Ventricles

A interconnected network of four fluid-filled cavities within the brain (two lateral, third, and fourth) where cerebrospinal fluid is produced.

Choroid plexuses

Vascular networks present inside all brain ventricles where blood is continuously filtered to produce cerebrospinal fluid.

Blood-brain barrier (BBB)

A selective physiological barrier consisting of tight junctions between capillary endothelial cells and astrocyte processes that regulates nutrient delivery and blocks toxins.

Brainstem

The most caudal and evolutionarily ancient part of the brain consisting of the midbrain, pons, and medulla oblongata.

Reticular formation

An interconnected core of grey matter nuclei in the brainstem responsible for vital survival functions such as alertness, breathing, cardiovascular tone, and pain modulation.

Midbrain

The superior segment of the brainstem developed around the cerebral aqueduct, containing colliculi, red nuclei, substantia nigra, and cerebral peduncles.

Pons

The intermediate brainstem structure composed largely of transverse fiber tracts connecting the brainstem to the cerebellum via cerebellar peduncles.

Medulla oblongata

The lowest, most caudal portion of the brainstem containing the pyramids on its ventral side, olives laterally, and gracile and cuneiform nuclei dorsally.

Diencephalon

The brain division developed around the third ventricle that contains the thalamus, hypothalamus, and epithalamus (pineal gland).

Basal ganglia

Deep cerebral grey matter nuclei consisting of the caudate nucleus, putamen, and globus pallidus that coordinate and initiate movements.

Amygdala

A temporal lobe structure involved in processing emotions related to fear, dislike, and aversion.

Hippocampus

A temporal lobe structure located dorsal to the amygdala that is essential for memory consolidation and learning processes.

Corpus callosum

A major white matter commissure situated superior to the lateral ventricles that connects the left and right cerebral hemispheres.

Conus medullaris

The tapered terminal inferior end of the spinal cord located near the L1 vertebra.

Cauda equina

The collection of descending spinal nerve roots found within the vertebral canal inferior to the spinal cord from L2 downward.

Dermatome

A designated cutaneous area innervated by the sensory fibers of a single specific spinal nerve.

Sympathetic division

The thoracolumbar autonomic division mediating fight-or-flight responses, characterized by preganglionic acetylcholine release and postganglionic release of adrenaline or noradrenaline.

Parasympathetic division

The craniosacral autonomic division mediating rest-and-digest functions, characterized by acetylcholine release at both preganglionic and postganglionic synapses.