Nervous System Flashcards
CNS
Brain & Spinal Cord
PNS
Spinal nerves (31) Cranial Nerves (12)
Somatic
Voluntary
Mucle,
Sesnsation
Development of the Spinal Cord
Nerulation ( starts at 3 weeks)
Neruolation
Notochord, Neural Plate, Neruall fold, Neural tube( nerual crest)
Process where neural plate forms the nerual tube
How do nerual folds form?
Lateral edges of neural plate become elavated
Neural Groove
a depressed mid region
Closure of cranial & caudal neuorpopre
25& 28
Neural Crest cells break off of what?
Nerual plate (epithelial layer of deveolping dorsal neraul tube)
What do the neural cells migrate to?
Mesenchymal cells
WHere to crest cells travel to?
Dorsal root ganglion ANS ganglian Ganglia to CN V, VII, IX, X Schwan cells Meninges Pigment cells MS components of head
Shwan cells are important in?
PNS
Each Schwan cells develop
myelin
Myelin are layers of what?
Layers of lipid and protein
What does Myelin form?
Sheat around some axons
What is myelin important for?
transmitting nervous impulse from neurons to neruon
CNS Structure
- Nucleus
a. Gray Matter
collection of NERVE CELL BODIEs - Tract
a. White matter
COllection of nerve fibers & connects nuclei
PNS structure
1. Ganglion Collection of nerve cell bodies Outside of CNS 2. Peripheral Nerve - Collection of nerve fibers, connects cns with peripheral structures such as spinal cord or cranial
Periphinal Spinal nerves
C1, C2, 3,4
Axons are white or gray matter?
white
Where can you find the cell bodies?
Nucleus, Gray matter
The SPinal Cord is the extension of what?
Brainstem from medulla
Where does the spinal cord end?
L1- L2
Primary fucntion of the spinal cord is to
transmit signals to and from the brain to peripheral structures
Dorsal & Ventral root meet to make what?
Spinal Nerve
Cross Sectional Vartiation
C
T
S
L
Describe Cervical Cross section
Large & oval
Large amount of white matter
Have the descending motor tract exit the cervical cross-sectional of the spinal cord?
No
Describe Thoracic Cross Section
Oval Shap
SMaller than cervical
Have lateral horns
- Autonomic
Where are the cell bodies of the sympathetic nervous located?
thoracic
Describe Lumbar Spine Cross Section
Round in shape & large
Largest amount of gray matter
why is their large amount of gray matter?
because the surface area of muscles and sensory fibers
Sacral Cross Section
Similar to lumbar but smaller
Have most descending tracts left the Sscral cross section?
Yes
Have ascending tracts ented the Spinal cored in sacral cross section?
Yes
