Cells of the Nervous System

Flashcards covering the cells of the nervous system, including the structure and function of neurons and various types of neuroglia in both the CNS and PNS, as well as the organization of nervous tissue.

Neurons (Nerve Cells)

Cells that receive stimuli and transmit action potentials.

Cell body (Soma)

The main part of a neuron containing the nucleus; receives stimuli and transmits signals.

Dendrites

Short, branched extensions of the neuron cell body that serve as the input part of the neuron.

Axons

Long, slender extensions of a neuron that serve as the output part, transmitting signals away from the cell body.

Neuroglia (Glial Cells)

Non-neural cells in the nervous system that support and protect neurons.

Axon Hillock

The cone-shaped area of the neuron cell body where the axon arises.

Initial Segment

The beginning part of the axon, immediately distal to the axon hillock.

Presynaptic Terminal (Synaptic End Bulb)

The terminal end of an axon, where neurotransmitters are released.

Axonal Transport

The cellular process responsible for movement of materials (like neurotransmitters in vesicles) between the cell body and the axon terminals.

Synaptic Vesicles

Small sacs in the presynaptic terminal that store and release neurotransmitters.

Sensory (Afferent) Neurons

Neurons that transmit action potentials toward the Central Nervous System (CNS).

Motor (Efferent) Neurons

Neurons that transmit action potentials away from the Central Nervous System (CNS) to effector organs.

Interneurons (Association Neurons)

Neurons located entirely within the Central Nervous System (CNS) that transmit signals from one neuron to another.

Multipolar Neuron

A type of neuron with many dendrites and a single axon, common in the CNS and as motor neurons.

Bipolar Neuron

A type of neuron with one dendrite and one axon, typically found in sensory organs like the eye.

Pseudo-unipolar (Unipolar) Neuron

A type of neuron with a single process extending from the cell body that divides into two branches, often functioning as sensory receptors in the periphery for general senses.

Astrocytes

Star-shaped neuroglial cells in the CNS that form foot processes covering blood vessels, neurons, and pia mater, contributing to the Blood Brain Barrier.

Blood Brain Barrier (BBB)

A protective barrier formed by tight junctions between endothelial cells of capillaries in the CNS, regulated by astrocytes, which prevents toxic substances from entering the brain.

Ependymal Cells

Neuroglial cells that line the ventricles of the brain and the central canal of the spinal cord, helping to form the choroid plexus and move cerebrospinal fluid (CSF) with cilia.

Microglia

Specialized macrophage-like neuroglial cells in the CNS that are phagocytic, removing dying tissue, microorganisms, and foreign substances.

Oligodendrocytes

Neuroglial cells in the CNS that form myelin sheaths around portions of several axons.

Schwann Cells

Neuroglial cells in the Peripheral Nervous System (PNS) that wrap around axons to form myelin sheaths around a portion of only one axon.

Satellite Cells

Neuroglial cells in the Peripheral Nervous System (PNS) that surround neuron cell bodies in ganglia and provide nutrients.

Myelin Sheath

A fatty, protective, and insulating layer formed by Schwann cells (PNS) or oligodendrocytes (CNS) around axons, increasing signal conduction speed.

Myelinated Axons

Axons covered with a myelin sheath, which conduct signals more rapidly.

Node of Ranvier

Gaps or interruptions in the myelin sheath along an axon.

Tract (CNS)

A bundle of myelinated axons within the Central Nervous System.

Nucleus (CNS)

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

White Matter

Regions of the Central Nervous System consisting primarily of myelinated axons, responsible for propagating action potentials.

Gray Matter

Regions of the Central Nervous System consisting of unmyelinated axons, cell bodies, dendrites, and neuroglia, primarily involved in integrative functions.