CNS II: Spinal Cord

Neurons

• Basic functional units

• Cells that receive and transmit information

• Cells that receive information

• Classified according to functional and structural characteristics

• Main goal → Send chemically driven electricity

Dendrites

stimulated by environmental changes or activities of other cells

Cell body

Contains nucleus and other other organelles

Axon

Conducts nervous impulse to distal end of neuron

Synaptic Terminals

Connection with other neurons or organ

Cell body

• Contains typical cellular organelles: Nucleus, mitochondria, Golgi

• No mitosis- related organelles: Neurons don’t divide

• Neurofibril cytoskeleton: Supports and maintains neuron shape

Nucleus

Clusters of neuronal cell bodies in CNS

Ganglion

Cluster of neuronal cell bodies in PNS

Tracts

Bundles of axons in CNS

Depolarization

caused by efflux of Na+ ions into cell through ion channels

What travels along cell membrane in one direction?

“Wave of negativity”

Repolarization

Caused by efflux of K+ ions to outside of cell

Spinal Cord

• Other CNS component along with Brain

• Links peripheral body to brain

• Distributes impulses along peripheral nerves

• Carries sensory and motor information

The spinal cord begins at the… where it meets the…

• Foramen magnum

• Medulla