Nervous System Anatomy and Physiology Flashcards

Comprehensive vocabulary flashcards covering nervous system functions, cellular components, action potential electrophysiology, embryonic brain development, central brain regions, and peripheral structures based on lecture notes.

Central Nervous System (CNS)

The control center of the nervous system consisting of the brain inside the skull and the spinal cord inside the vertebral column.

Peripheral Nervous System (PNS)

The structural division of the nervous system comprising all neural tissues outside the brain and spinal cord, including nerves and ganglia.

Neuron

The fundamental nervous system cell specialized for sending and receiving electrical messages and communicating information.

Dendrite

A highly branched neuron process that receives incoming signals and carries information into the cell body.

Soma

The cell body of a neuron that contains the nucleus and organelles, maintaining cellular life and function.

Axon

A neuron process that conducts nerve impulses away from the cell body toward target cells.

Glial Cells

Supportive cells found in the CNS and PNS that protect, nourish, support neurons, and produce myelin.

Gray Matter

Nervous system tissue composed predominantly of neuron cell bodies and dendrites.

White Matter

Nervous system tissue composed predominantly of myelinated axons.

Myelin

A fatty covering around an axon that provides electrical insulation and accelerates signal conduction.

Nucleus (CNS)

A localized collection of neuron cell bodies located within the Central Nervous System.

Ganglion

A localized collection of neuron cell bodies located within the Peripheral Nervous System.

Tract

A bundle of axons located within the Central Nervous System.

Nerve

A bundle of axons along with connective tissue and blood vessels located within the Peripheral Nervous System.

Sensation

The nervous system function of receiving sensory input by detecting stimuli inside or outside the body.

Integration

The nervous system function of processing, interpreting, and deciding upon sensory input.

Response

The nervous system function of producing a motor output acting on muscles or glands.

Afferent

Refers to sensory input traveling toward the Central Nervous System.

Efferent

Refers to motor output traveling away from the Central Nervous System.

Somatic Nervous System

Functional division associated with conscious perception and voluntary movement of skeletal muscles.

Autonomic Nervous System

Functional division controlling automatic, involuntary functions such as smooth muscle, cardiac muscle, and glands to maintain homeostasis.

Enteric Nervous System

Autonomous nervous division associated with the digestive system that controls smooth muscle and glands in the digestive tract independently of the CNS.

Trigger Zone

The functional region formed by the axon hillock and initial segment where action potentials are generated.

Nodes of Ranvier

Small unmyelinated gaps along an axon between segments of myelin sheath.

Synapse

The functional communication point or connection between a neuron and another cell.

Unipolar Neuron

A neuron with a single process extending from the cell body that acts exclusively as a sensory neuron with its cell body in a ganglion.

Bipolar Neuron

A rare neuron shape featuring two processes (one dendrite and one axon) extending from opposite sides of the soma, located in olfactory tissue and the retina.

Multipolar Neuron

The most common neuron type featuring one axon and two or more dendrites, characteristic of motor neurons.

Astrocytes

Star-shaped CNS glial cells that support neurons, regulate chemical environments, and help form the blood-brain barrier (BBB).

Oligodendrocytes

CNS glial cells that produce myelin sheaths around multiple axon segments.

Microglia

Phagocytic CNS glial cells that act as immune defense by detecting and removing damaged cells and pathogens.

Ependymal Cells

CNS glial cells lining brain ventricles that produce cerebrospinal fluid (CSF).

Satellite Cells

PNS glial cells that surround and support neuron cell bodies within ganglia.

Schwann Cells

PNS glial cells responsible for creating myelin wrapped around a single segment of an axon.

Multiple Sclerosis (MS)

An autoimmune disease characterized by demyelination within the Central Nervous System.

Guillain-Barré Syndrome

An autoimmune disease characterized by demyelination within the Peripheral Nervous System.

Graded Potential

A local change in membrane potential on dendrites or soma whose magnitude directly depends on the strength of the stimulus.

Threshold

The critical membrane potential voltage level of approximately $-55\, \text{mV}$ required to initiate an action potential.

Resting Membrane Potential

The steady charge difference across a resting neuron cell membrane, measured at approximately $-70\, \text{mV}$.

Depolarization

A change in membrane potential making the inside of the cell less negative, driven by an influx of $\text{Na}^+$ ions up to approximately $+30\, \text{mV}$.

Repolarization

The restoration of a negative membrane potential following depolarization, driven by an efflux of $\text{K}^+$ ions out of the cell.

Hyperpolarization

A temporary phase where membrane potential becomes more negative than the resting $-70\, \text{mV}$ level due to delayed closure of $\text{K}^+$ channels.

Sodium-Potassium Pump

An active transport pump that uses ATP to move $3\, \text{Na}^+$ ions out of the cell and $2\, \text{K}^+$ ions into the cell.

Absolute Refractory Period

The timeframe following an action potential during which a second action potential cannot be generated under any stimulus.

Relative Refractory Period

The recovery timeframe during which a second action potential can be triggered, but only by a stronger-than-normal stimulus.

Continuous Conduction

The slow propagation of an action potential along the entire unmyelinated axon membrane.

Saltatory Conduction

The rapid propagation of an action potential jumping from node to node along a myelinated axon.

EPSP (Excitatory Postsynaptic Potential)

A depolarizing graded potential in a postsynaptic neuron that moves the membrane potential closer to threshold.

IPSP (Inhibitory Postsynaptic Potential)

A hyperpolarizing graded potential in a postsynaptic neuron that moves the membrane potential further from threshold.

Temporal Summation

The addition of multiple graded potentials occurring at the same physical location at separate times.

Spatial Summation

The addition of multiple graded potentials occurring at different physical locations on a neuron simultaneously.

Ionotropic Receptor

A neurotransmitter receptor protein that functions directly as a ligand-gated ion channel.

Metabotropic Receptor

A neurotransmitter receptor complex involving G proteins and effector enzymes that generates intracellular second messengers like $\text{cAMP}$ or $\text{IP}_3$.

Neural Tube

An embryonic structure formed from neuroectoderm that develops into the Central Nervous System.

Neural Crest

Embryonic neural tissue that detaches during tube formation to give rise to PNS structures and enteric nervous tissue.

Prosencephalon

The primary brain vesicle known as the forebrain, which gives rise to the telencephalon and diencephalon.

Mesencephalon

The primary brain vesicle known as the midbrain, which persists as the midbrain in the adult brain structure.

Rhombencephalon

The primary brain vesicle known as the hindbrain, which gives rise to the metencephalon and myelencephalon.

Telencephalon

The secondary brain vesicle derived from the prosencephalon that develops into the adult cerebrum.

Diencephalon

The secondary brain vesicle derived from the prosencephalon that develops into the thalamus, hypothalamus, epithalamus, and subthalamus.

Metencephalon

The secondary brain vesicle derived from the rhombencephalon that develops into the pons and cerebellum.

Myelencephalon

The secondary brain vesicle derived from the rhombencephalon that develops into the medulla oblongata.

Cephalic Flexure

A major bend in the embryonic neuraxis that establishes the anatomical orientation of the human brain.

Corpus Callosum

A large structure of white matter tracts connecting the left and right cerebral hemispheres.

Frontal Lobe

The anterior cerebral lobe controlling voluntary movement, motor functions, personality/behavior, short-term memory, and consciousness.

Parietal Lobe

The cerebral lobe responsible for processing somatic sensory information including touch, pain, pressure, and body position.

Temporal Lobe

The cerebral lobe responsible for auditory information processing, hearing, long-term memory, and limbic system connections.

Occipital Lobe

The posterior cerebral lobe primarily responsible for visual processing.

Precentral Gyrus

The gyrus located in the frontal cortex that contains upper motor neurons responsible for initiating motor commands.

Postcentral Gyrus

The gyrus located in the parietal lobe responsible for primary somatic sensory perception.

Broca's Area

A functional area located in the left frontal lobe responsible for speech production.

Wernicke's Area

A functional area located in the left temporal region responsible for speech comprehension.

Thalamus

A diencephalic region that acts as a sensory relay station, relaying all sensory input to the cerebral cortex except smell.

Hypothalamus

A key diencephalic structure regulating homeostasis, the autonomic nervous system, endocrine system, and pituitary gland.

Medulla Oblongata

The inferior portion of the brainstem regulating vital autonomic functions including heart rate, breathing, and cardiovascular control.

Cerebellum

The 'little brain' structure located posterior to the brainstem that coordinates and fine-tunes movement without initiating it.

Circle of Willis

An arterial ring formed by internal carotid and basilar artery branches supplying blood to the brain and maintaining collateral circulation.

Dura Mater

The tough, outermost protective meningeal layer surrounding the CNS.

Arachnoid Mater

The middle meningeal layer separated from the pia mater by the subarachnoid space containing CSF.

Pia Mater

The delicate, vascularized innermost meningeal layer adhering directly to the surface of the brain and spinal cord.

Choroid Plexus

Specialized vascular tissue within brain ventricles that produces cerebrospinal fluid (CSF).

Subarachnoid Space

The fluid-filled space between the arachnoid mater and pia mater through which CSF circulates around the CNS.

Endoneurium

The connective tissue layer surrounding an individual axon inside a peripheral nerve.

Perineurium

The connective tissue layer surrounding a bundle of axons (fascicle) inside a peripheral nerve.

Epineurium

The outermost connective tissue layer enclosing an entire peripheral nerve.

Phrenic Nerve

A major nerve arising from the cervical plexus (C1–C5) that innervates the diaphragm.

Sciatic Nerve

A major nerve arising from the sacral plexus (L4–S4) that innervates the posterior leg.