Nervous System and Anatomy Review

This set of flashcards covers key vocabulary terms and concepts related to the nervous system and its anatomy.

Central Nervous System (CNS)

Consists of the brain and spinal cord, responsible for processing information.

Peripheral Nervous System (PNS)

Comprises all the nerves and ganglia outside the CNS.

Neuroglia

Supportive cells in the nervous system that protect neurons and maintain homeostasis.

Neuron

The functional cell of the nervous system tasked with transmitting nerve impulses.

Dendrites

Branches of a neuron that receive signals from other neurons.

Axon

The long pathway of a neuron that conducts impulses away from the cell body.

Action Potential

A rapid electrical signal that travels along the axon of a neuron.

Resting Membrane Potential (RMP)

The electrical potential difference across the plasma membrane of a neuron at rest, typically -70 mV.

Myelin Sheath

An insulating layer around a nerve fiber that increases the speed of impulse transmission.

Synapse

The junction between two neurons where neurotransmitters are released.

Neurotransmitter

Chemicals released from synaptic knobs that transmit signals across synapses.

Astrocytes

The most abundant type of neuroglia in the CNS, involved in supporting neurons and forming the blood-brain barrier.

Oligodendrocytes

Glial cells that form myelin sheaths around axons in the CNS.

Microglia

Immune cells in the CNS that clean up debris and respond to damage.

Ependymal Cells

Line the brain's internal cavities and secrete cerebrospinal fluid.

Schwann Cells

Glial cells in the PNS that wrap around nerve fibers to form the myelin sheath.

Satellite Cells

Surround neuron cell bodies in ganglia, providing insulation and regulating the chemical environment.

Trigger Zone

The area of a neuron where action potentials are initiated, typically near the axon hillock.

Local Potential

Small, localized changes in membrane potential that may trigger action potentials if strong enough.

Absolute Refractory Period

The phase during which a neuron cannot fire a second action potential, regardless of stimulus strength.

Relative Refractory Period

The phase where a strong stimulus can initiate a second action potential.

Saltatory Conduction

The process by which action potentials jump between nodes of Ranvier in myelinated neurons.

Continuous Conduction

A manner of conducting action potentials in unmyelinated fibers, where the signal is propagated along the entire axon.

Resting Potentials

The electrical charge difference across the membrane of a non-signaling neuron.

Threshold

The minimum depolarization needed to trigger an action potential, about -55 mV.

Neuromuscular Junction

A synapse between a motor neuron and a muscle fiber, where neurotransmitters cause muscle contraction.

Neurons Classification

Neurons can be classified by structure, function, or the direction in which they transmit impulses.

Sensory (Afferent) Neurons

Neurons that transmit sensory signals to the CNS.

Interneurons

Neurons that connect sensory and motor neurons within the CNS.

Motor (Efferent) Neurons

Neurons that send signals from the CNS to effectors (muscles and glands).

Neuronal Injury Regeneration

The ability of peripheral nerves to regenerate after injury, influenced by Schwann cells.

Cerebrospinal Fluid (CSF)

Fluid that cushions the brain and spinal cord, produced by ependymal cells.

Endoneurium

A thin layer of connective tissue surrounding individual nerve fibers in the PNS.

Myelination Process

The production of myelin sheath that begins during fetal development and continues into late adolescence.

Potassium (K+) Role in RMP

K+ ions create the resting membrane potential, as they diffuse out of the neuron.

Sodium (Na+) Role in RMP

Na+ ions slightly influence RMP, contributing to depolarization during action potentials.

Ligand

A molecule that binds to a receptor, initiating a signaling event in the neuron.

Electrophysiology

The branch of physiology that studies the electrical properties of biological cells and tissues.

Chemical Synapse

A synapse where neurotransmitters are released from synaptic knobs to transmit signals.

Glial Cells

Cells in the nervous system that support, protect, and maintain the environment for neurons.

Neuron Structure

Neurons consist of a soma (cell body), dendrites, and an axon.

Inclusions in Neurons

Cellular structures such as glycogen and pigments found within the neuron.

Tay–Sachs Disease

A genetic disorder caused by the accumulation of GM2 due to a missing enzyme, affecting neural function.

Multiple Sclerosis

A disease characterized by the degeneration of myelin sheaths in the CNS, disrupting signal conduction.

Na+/K+ Pump

A membrane protein that maintains the resting membrane potential by moving 3 Na+ out and 2 K+ in.

Nissl Bodies

Aggregates of rough endoplasmic reticulum in the soma of neurons, used for protein synthesis.

Mitochondria in Neurons

Organelles in the neuron responsible for energy production.