Nervous System Flashcards
Branches of Peripheral Nervous System
Somatic, Autonomic
What kind of nerves are contained in the Somatic nervous system
Peripheral
Where is the border between the CNS and PNS
The most superficial layer of the spinal cord (Spinal cord stops at around L2)
Name of area where spinal cord stops
Conus Medullaris
Base unit of the CNS and PNS
Neurons
Components of Neurons
Cell Body (grey matter), Axon, Myelin sheaths (white matter)
Part of the PNS under conscious control
Somatic
Another name for motor neurons
Efferent
Another name for sensory neurons
Afferent
Location of efferent neuron cell bodies
Ventral horn of spinal cord
Location of afferent neuron cell bodies
dorsal root ganglion
layer that surrounds a fascicle of nerves
perineurium
Motor Unit
a single nerve + all the muscle fibres it innervates
How many pairs of spinal nerves (in each section)
31 total (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal)
what area does the dorsal ramus supply
local posterior muscle + skin (dermatomes)
what areas do the ventral rami supply
plexuses (limbs)
Where does a ramus form
intervertebral foramen
Neurons that connect sensory and motor neurons
interneurons
what is a plexus
an intertwining network of nerves that give rise to peripheral nerves that supply structures of the arm/leg
Largest nerve in the lumbosacral plexus
sciatic
Lateral femoral cutaneous nerve source
L2,L3
Femoral Nerve source/target
L2-L4 (posterior)/anterior hip and thigh (hip flexors, knee extensors)
Obturator nerve source/target
L2-L4 (anterior)/medial thigh (hip adductors)
Accessory Obturator
L3,L4 (not everyone has one)
