6.1-6.4 Cells of the Nervous System

Flashcards covering the cells and structure of the nervous system.

Central Nervous System (CNS)

Composed of the brain and spinal cord.

Peripheral Nervous System (PNS)

Consists of the nerves that connect the brain and spinal cord with the body’s muscles, glands, sense organs, and other tissues.

Neuron

The functional unit of the nervous system that operates by generating electrical signals.

Neurotransmitters

Chemical messengers released by neurons to communicate with other cells.

Glial Cells

Non-neuronal cells that provide supportive functions for neurons.

Cell Body (Soma)

Contains the nucleus and ribosomes, providing genetic information and machinery for protein synthesis in a neuron.

Dendrites

Branched outgrowths of a neuron that receive incoming information from other neurons.

Dendritic Spines

Knoblike outgrowths that increase the surface area of dendrites.

Axon

A long process extending from the cell body that carries outgoing signals to target cells.

Axon Hillock (Initial Segment)

The region of the axon where propagated electrical signals are generated.

Collaterals

Branches of the axon.

Axon Terminal

The end of an axon branch responsible for releasing neurotransmitters.

Varicosities

Bulging areas along the axon that release chemical messengers.

Myelin

Sheaths covering the axons of many neurons, speeding up electrical signals and conserving energy.

Oligodendrocytes

Glial cells in the brain and spinal cord that form myelin on axons.

Schwann Cells

Glial cells in the PNS that form individual myelin sheaths around axon segments.

Nodes of Ranvier

Spaces between adjacent sections of myelin where the axon’s plasma membrane is exposed.

Axonal Transport

Movement of organelles and materials between the cell body and axon terminals.

Kinesin

Motor proteins involved in anterograde axonal transport (from cell body to axon terminals).

Dynein

Motor proteins involved in retrograde axonal transport (from axon terminals to cell body).

Afferent Neurons

Convey information from tissues and organs towards the CNS.

Efferent Neurons

Convey information away from the CNS to effector cells.

Interneurons

Connect neurons within the CNS.

Sensory Receptors

Respond to physical or chemical changes in the environment by generating electrical signals in the neuron.

Nerves

Collections of neuron axons encased in connective tissue, located in the PNS.

Synapse

Anatomically specialized junction between two neurons where one neuron alters the electrical and chemical activity of another.

Presynaptic Neuron

A neuron that conducts a signal toward a synapse.

Postsynaptic Neuron

A neuron conducting signals away from a synapse.

Astrocytes

CNS glial cells that regulate extracellular fluid composition, stimulate tight junctions forming the blood-brain barrier, and sustain neurons metabolically.

Blood-Brain Barrier

A selective filter for exchanged substances between the blood and the CNS.

Microglia

CNS glial cells that perform immune functions and contribute to synapse remodeling.

Ependymal Cells

Line fluid-filled cavities within the brain and spinal cord and regulate the production and flow of cerebrospinal fluid.

Growth Cone

A specialized enlargement that forms the tip of each extending axon and is involved in finding the correct target during neural growth.