Central Nervous System Communication: Neurons and Glia

Central Nervous System Communication: Neurons and Glia

 

Cells/structures Types Functions Features
Neurons Sensory neurons Transform physical energy -> sense messages -> the brain Compose the afferent tracts of the nervous system
Motor neurons Transmit information from the brain -> muscles, organs Compose the efferent tracts of the nervous system
Interneurons Transmit communications between neurons Most plentiful in the brain
Glia/glial cells: supporting cells (composed mostly of fat) Structural support
Faster communications between neurons, e.g., via myelin
Healing from injuries and infections
Cleaning of the wastes and dead neurons

 

 

Gray Matter and White Matter

 

Parts Cells/structures
Gray matter Neuron
Astrocyte
Capillary
Microglia
Oligodendrocyte
White matter Axon
Myelin
Unmyelinated axon
Capillary
Astrocytes
Oligodendrocyte

 

 

Structures and Functions of Neurons

 

Structures Substructures Functions
Cell membrane Holds the cell
Nucleus Chromosomes, genetic materials Growth of nervous tissues
Cell body/soma Organelles (Mitochondria, Golgi bodies) Protein production, metabolism, waste excretion
Dendrites Receptors Receiving chemical messages
Axons Myelin (to speed transmission), nodes of Ranvier (gaps in the myelin) Sending electronic signals
Synapses (gaps between the (sending) axon and the (receiving) dendrite) Presynaptic terminal, vesicles with neurotransmitters Transmission across the synapse to the receptors

 

 

The Action Potential of Neurons

 

 

Functions States Details Features
Resting potential No communication, polarization Internal charge – negative; surrounding area – positive
Action potential Depolarization Firing; positive charge -> synapse All-or-nothing (with the stimulus threshold)
Refractory period (resting); hyperpolarized
Synaptic transmission of neurotransmitters ->reuptake -> recycled
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