Anatomy & Physiology: The Nervous System

Flashcards covering the structural and functional organization of the nervous system, including support cells, neuron anatomy, brain regions, and spinal cord protection.

Sensory input

The function of the nervous system involving gathering information by monitoring changes (stimuli) occurring inside and outside the body.

Integration

The process by which the nervous system processes and interprets sensory input and decides what action is needed.

Motor output

The response that activates muscles or glands after the nervous system has integrated stimuli.

Central nervous system (CNS)

The structural classification of the nervous system that acts as the command center, consisting of the brain and spinal cord.

Peripheral nervous system (PNS)

The structural classification of the nervous system consisting of nerves extending from the brain (cranial nerves) and spinal cord (spinal nerves).

Sensory (afferent) division

Nerve fibers that carry information from somatic or visceral receptors to the CNS.

Motor (efferent) division

Nerve fibers that carry impulses away from the CNS to effector organs, muscles, and glands to produce a motor response.

Somatic nervous system

A subdivision of the motor division that allows for voluntary control of skeletal muscles.

Autonomic nervous system

A subdivision of the motor division that regulates involuntary (automatic) activity of smooth and cardiac muscles and glands.

Neuroglia

The group of support cells in the CNS also known as "glial cells" that support, insulate, and protect neurons.

Astrocytes

CNS support cells that anchor neurons to capillaries and form a barrier to regulate material exchange.

Microglia

Spider-like phagocytes in the CNS that dispose of debris.

Ependymal cells

Support cells that line the cavities of the brain and spinal cord and use cilia to circulate cerebrospinal fluid (CSF).

Oligodendrocytes

CNS support cells that wrap around nerve fibers to produce lipid-based myelin sheaths.

Satellite cells

Support cells in the PNS that protect neuron cell bodies.

Schwann cells

PNS support cells that form myelin sheaths around nerve fibers.

Cell body

The metabolic center of the neuron containing the nucleus and neurofibrils.

Dendrites

Neuron processes that conduct electrical impulses toward the cell body.

Axons

Neuron processes that conduct electrical impulses away from the cell body, emerging from the axon hillock.

Synapse

The junction between two nerves where signals are transmitted.

Synaptic cleft

The tiny gap that separates the axonal terminal of one neuron from the next neuron.

Myelin sheath

A whitish, fatty material that covers axons to protect, insulate, and increase the transmission rate of impulses.

Nodes of Ranvier

Gaps in the myelin sheath along the length of an axon.

Nuclei

Clusters of neuron cell bodies found within the Central Nervous System.

Ganglia

Clusters of neuron cell bodies found in the Peripheral Nervous System.

Tracts

Bundles of nerve fibers (axons) running through the Central Nervous System.

Nerves

Bundles of nerve fibers (axons) found in the Peripheral Nervous System.

Gray matter

Regions of the CNS containing primarily cell bodies and unmyelinated fibers.

White matter

Regions of the CNS containing dense collections of myelinated fibers (tracts).

Interneurons

Also called association neurons, these connect sensory and motor neurons in neural pathways within the CNS.

Reflex arc

A neural pathway over which a rapid, predictable, and involuntary response (reflex) occurs.

Cerebrum

The paired superior parts of the brain consisting of two hemispheres characterized by gyri, sulci, and fissures.

Gyri

Elevated ridges of tissue on the surface of the cerebral hemispheres.

Sulci

Shallow grooves on the surface of the cerebral hemispheres.

Fissures

Deep grooves that divide the cerebrum into different lobes.

Primary somatic sensory area

Located in the postcentral gyrus of the parietal lobe; it receives impulses from sensory receptors for pain, cold, and touch.

Primary motor area

Located in the precentral gyrus of the frontal lobe; it sends impulses to skeletal muscles.

Broca’s area

A specialized area of the cerebral cortex involved in the motor ability to speak and vocalize properly.

Corpus callosum

A large fiber tract that connects the two cerebral hemispheres, allowing them to communicate.

Basal nuclei

Islands of gray matter buried deep within the white matter of the cerebral hemispheres.

Diencephalon

The region of the brain sitting on top of the brain stem, composed of the thalamus, hypothalamus, and epithalamus.

Thalamus

The relay station for sensory impulses passing upward to the cerebral cortex for interpretation.

Hypothalamus

An important autonomic center that regulates body temperature and metabolism, and serves as part of the limbic system (emotions).

Midbrain

The most superior part of the brain stem, composed primarily of fiber tracts.

Pons

The bulging center part of the brain stem involved in fiber tracts and nuclei that help control breathing.

Medulla Oblongata

The most inferior part of the brain stem that merges into the spinal cord; contains control centers for heart rate, blood pressure, breathing, and swallowing.

Cerebellum

The brain region located under the occipital lobe responsible for involuntary coordination of body movements, balance, and equilibrium.

Meninges

The three connective tissue membranes (dura mater, arachnoid mater, pia mater) that cover and protect CNS structures.

Cerebrospinal fluid (CSF)

A watery cushion formed from blood by choroid plexuses that protects the brain and circulates in the subarachnoid space.

Blood-brain barrier

A mechanism composed of the least permeable capillaries in the body that prevents toxins and most drugs from entering brain tissue.

Cauda equina

The collection of spinal nerves at the inferior end of the vertebral canal, named for its resemblance to a horse's tail.