Lecture 3 Flashcards
Nervous system classification
CNS (Brain and Spinal Cord), PNS (everything else, divided into spinal and cranial nerves)
orienting spinal cord/vertebra
Spinal process is posterior, split in spinal cord is anterior
spinal cord white and grey matter orientation
Gray matter is in the inside, white matter is in the outside (flipped from brain). Gray matter is where the cell bodies are, white matter is axons
Tract
Collection of axons/fibers found w/i CNS
Nucleus
Collection of somas found within CNS, not to be confused with nucleus at a cell
Nerve
A collection of nerve cell processes found outside the CNS
Layers of Nerve Trunk
outer covering epineurium –> sorrounds multiple fascicles/fasiculus–>Each one covered by a perineurium
–>each fascicle/fasiculus contains multiple neurons –> each neuron myelin sheath surrounded by endoneurium
Ganglia
Collection of nerve cell bodies (somas) found outside the CNS. notably the dorsal root ganglion
Afferent vs. Efferent
Afferent are sensory axons conduction electrical impulses towards the CNS in dorsal root. Are often unipolar
Efferent are motor axons conducting electrical impulses towards the PNS in ventral root. Are often bipolar
dermatoms
Different skin segments related to different spinal nerves
dorsal root vs. ventral root
Dorsal root only contains afferent nerves, ventral root contains only efferent nerves. In spinal nerve the two fibers co-exist
Reflex Arc
Goes through the dorsal root ganglion, afferent–>interneuron (almost always here)–>efferent (ventral root) OR afferent –> inhibitory neuron –> Efferent.
Dorsal Ramus innervates?
Deep back muscles, Overlying Skin
Ventral Ramus innervates
Everything else, including superficial and intermediate back muscles
spinal nerves naming
C1-C7 names for vertebra under nerve, nerve C8 has T1 vertebra under it, Nerves T1-C1 named for vertebra above nerve. T1 nerve located between T1 and T2, below T1.
Conus medullaris
End of the spinal cord, ends in a cone around L1/L2.
Cauda Equina
The nerves extending beyond the root of the spinal cord, looks like a horse’s tail.
Filium Terminale
Not paired, not a nerve, just the end of the pia mater that extends down from the conus medullaris. Helps anchor the lower part of the spinal cord
Spinal Meninges
Dura mater (hard), Arachnoid Mater (webby), Pia Mater (delicate, cannot be distinguished from surface of the spinal cord)
Epidural Space
Outside the dura mater, inside vertabral foramen, where anesthesia is placed, bc gets rid of the sensory while maintaining the motor
Subarachnoid space
Between arachnoid/pia layers. Space large enough around cauda equina to safely withdraw cerebral spinal fluid.
Denticulate ligaments
Extension of the pia mater that inserts into the dura mater, anchors the spinal cord within the vertebral column
