b241 w23 s12 nervous system

Neuroglia

Supportive cells in the nervous system that outnumber neurons and help maintain the environment around neurons.

Central Nervous System (CNS)

Composed of the brain and spinal cord; processes information and issues commands.

Peripheral Nervous System (PNS)

Contains all nervous system components outside the brain and spinal cord, including nerves and ganglia.

Neuron

A nerve cell that transmits nerve impulses; consists of a soma, dendrites, and an axon.

Myelin Sheath

An insulating layer surrounding some axons that increases the speed of action potential conduction.

Action Potential

A rapid electrical signal that travels along an axon and is the primary means of communication between neurons.

Excitable Cells

Cells such as neurons and muscle cells that can generate electrical signals or impulses.

Synapse

A junction where a neuron communicates with another neuron or a target cell, typically involving neurotransmitter release.

Neurotransmitter

Chemical messengers released by neurons that transmit signals across a synapse.

Resting Membrane Potential (RMP)

The electrical charge difference across the plasma membrane of a resting neuron, typically around -70 mV.

Depolarization

A decrease in membrane potential, making the inside of the cell less negative.

Hyperpolarization

An increase in membrane potential, making the inside of the cell more negative.

Somatic Nervous System

Part of the peripheral nervous system that controls voluntary movements by affecting skeletal muscles.

Autonomic Nervous System

Part of the peripheral nervous system that controls involuntary functions, such as heart rate and digestion.

Dendrites

Extensions of neurons that receive signals from other neurons.

Axon

A long, singular projection from a neuron that transmits signals away from the soma.

Refractory Period

The period after an action potential during which a neuron is resistant to further stimulation.

Glial Cells

Non-neuronal cells that provide support, protection, and nutrition to neurons.

Neuron Classification

Neurons can be classified as sensory (afferent), motor (efferent), and interneurons based on their function.

Neuroplasticity

The brain's ability to change and adapt in response to experience or injury.

Signal Transduction

The process by which a chemical signal is transmitted through a cell as a series of molecular events.

Sensory Division

Part of the peripheral nervous system that transmits sensory information to the central nervous system.

Motor Division

Part of the peripheral nervous system that carries signals from the central nervous system to effectors, such as muscles and glands.