Intro to Nervous System 8.15 Flashcards
Central Nervous System Components
Central NS
– Brain
– Spinal cord
Peripheral Nervous System Components
Peripheral NS – Cranial nerves (12 pairs) – Spinal nerves (31 pairs) – Ganglia – Motor and sensory nerve endings
Ganglia
Clumps of cell bodies located outside of the CNS
Afferent NS
Afferent (inflowing information, usually sensory)
– Somatic (surface sensation)
– Visceral (organ sensation)
Efferent NS
Efferent (outflowing informations, EXITing information) – Somatic (motor) – Visceral (Autonomic) • Sympathetic (fight or flight) • Parasympathetic (rest-n-digest)
Main parts of the neuron
Neurons
– Cell body (soma)
– Dendrites
– Axon
Glia
“Glue”, supportive, non-neuronal cells. Also produce CSF, and myelinate axons
Neuron Types
– Unipolar (one body at a terminal end, one process, rare in humans)
– Bipolar (body located centrally)
– Pseudounipolar (body located central, as an offshoot)
– Multipolar (multiple dendrites shooting off of body, most common)
White vs Gray Matter
White Matter = neuron processes
Gray Matter = neuron cell bodies
– Cortex – Nuclei – Ganglia
Location of w/g matter in brain
White is central, gray is exterior
Location of w/g matter in spinal cord
White is exterior, gray is interior
Exit path of spinal cord segments
The spinal nerve of a given spinal cord segment exits the vertebral canal by passing through an intervertebral foramen.
Numbering of C-spinal nerves
Cervical spinal nerves emerge above their corresponding vertebra. The C8 spinal nerve emerges above the T1 vertebra.
Numbering of T/L-spinal nerves
Thoracic, Lumbar and Sacral spinal nerves emerge below their corresponding vertebra.
Conus Medullaris
The caudal end of the spinal cord (conus medullaris) ends at the L1/L2 vertebral level.