Anatomy 102 - Chapter 12 Neural Tissue Vocabulary Flashcards

Comprehensive key vocabulary flashcards derived from Anatomy 102 Chapter 12 lecture notes, covering divisions, glia, neuron anatomy, electrical potentials, propagation, and synapse mechanisms.

Sensory Input

Detection of a stimulus or change and transmission of that information toward the CNS.

Integration

Processing and interpretation of sensory information by the CNS.

Motor Output

Transmission of commands from the CNS to an effector such as a muscle or gland.

Central Nervous System (CNS)

The structural division of the nervous system made up of the brain and spinal cord.

Peripheral Nervous System (PNS)

Nervous tissue outside the CNS, including nerves and ganglia.

Afferent

Refers to sensory information traveling toward the CNS ('arrives').

Efferent

Refers to motor information traveling away from the CNS toward effectors ('exits').

Astrocyte

A CNS glial cell that supports neurons, helps maintain their environment, and interacts with blood vessels.

Oligodendrocyte

A CNS glial cell that produces myelin and can myelinate portions of multiple axons.

Microglia

A CNS glial cell that provides defense and cleanup by removing debris and pathogens.

Ependymal Cells

CNS glial cells that line CNS cavities and are associated with cerebrospinal fluid.

Schwann Cells

Glial cells that produce myelin in the PNS.

Satellite Cells

Glial cells that surround and support neuron cell bodies in PNS ganglia.

Dendrites

Structures of a neuron that receive information.

Soma (Cell Body)

The part of a neuron containing the nucleus and organelles that integrates incoming information.

Axon

Neuron extension that carries electrical signals away from the soma.

Axon Terminals

Structures at the end of an axon that release neurotransmitters to communicate with a target cell.

Initial Segment

The region of an axon where an action potential can begin when threshold is reached.

Tract

A bundle of axons in the CNS.

Nerve

A bundle of axons in the PNS.

Nucleus (Nervous System)

A collection of neuron cell bodies located in the CNS.

Ganglion

A collection of neuron cell bodies located in the PNS.

Myelin

Layers of glial-cell membrane wrapped around an axon that electrically insulates it and allows nerve impulses to propagate efficiently.

Node of Ranvier

A gap between myelinated segments of an axon that is important for saltatory propagation.

Unipolar Neuron

A neuron with one process.

Bipolar Neuron

A neuron with two processes.

Multipolar Neuron

A neuron with multiple processes.

Sensory (Afferent) Neuron

A neuron that carries information from receptors toward the CNS.

Motor (Efferent) Neuron

A neuron that carries commands from the CNS toward muscles or glands.

Interneuron

A neuron that communicates between neurons within CNS pathways and helps with processing and integration.

Resting Membrane Potential

The typical electrical potential across a resting neuron's membrane, which is $-70\,mV$.

Threshold Potential

The approximate membrane potential of $-55\,mV$ required to trigger an action potential.

Depolarization

The phase of an action potential in which $Na^+$ moves into the neuron and the membrane potential becomes more positive, reaching up to about $+30\,mV$.

Repolarization

The phase of an action potential in which $K^+$ moves out of the neuron and the membrane becomes negative again.

Hyperpolarization

The phase during which the membrane potential temporarily becomes more negative than the resting potential before returning to about $-70\,mV$.

Graded Potential

A local, temporary, variable change in membrane voltage whose size depends on stimulus strength and can depolarize or hyperpolarize.

Action Potential

An all-or-none electrical event that occurs after threshold is reached and propagates along the axon.

Continuous Propagation

Conduction along unmyelinated axons where the action potential is regenerated along successive portions of the membrane.

Saltatory Propagation

Fast conduction along myelinated axons where the action potential effectively travels from one node of Ranvier to the next.

Passive Channel

An ion channel (also known as a leak channel) that does not require a specific stimulus to open and helps establish the membrane's electrical properties.

Ligand-Gated Channel

An ion channel opened by the binding of a specific chemical ligand.

Mechanically Gated Channel

An ion channel opened by a physical or mechanical stimulus such as pressure or touch.

Voltage-Gated Channel

An ion channel opened by a change in membrane voltage.

Synapse

A connection between a neuron and its target cell.

Electrical Synapse

A synapse that allows direct electrical communication between cells without requiring neurotransmitter release across a synaptic cleft.

Chemical Synapse

A synapse in which an action potential triggers $Ca^{2+}$ entry, neurotransmitter release across the synaptic cleft, and binding to postsynaptic receptors.

Neurotransmitter

A chemical messenger released by a neuron to communicate with a target cell.

Ionotropic Receptor

A receptor in which neurotransmitter binding directly opens or closes an ion channel.

Metabotropic Receptor

A receptor that acts through a G protein and second-messenger system, such as cAMP.