Lecture5 Flashcards
Ependymal Layer
type of epithelia, forms the lining of all the ventricles, no ependymal brain barrier (anything into CSF can have effect on brain)
Marginal Layer
cell birth (neurons)
Embryonic Day 27
neural tube closed, ependymal layer, marginal layer, mantle layer, division in gray and white matters
Neural Crest
will develop into dorsal root ganglia (just making sure you didn’t forget this from earlier)
Embryonic Day 60
neural tube pinched off and created diamond shape to segregate neurons into place (anterior/basal plate, posterior/alar plate)
Basal Plate
anterior, motor neurons
Alar Plate
posterior, sensory neurons
Sulcus Limitans
groove that separates motor and sensory neurons
General Somatic Efferent
fibers that go away from the nervous system, motor
General Somatic Afferent
fibers that go to nervous system, sensory
Embryonic Day 100
two additional functional components added, general VISCERAL efferent and afferent
Four Functional Components of All Spinal Nerves
GSA, GVA, GVE, GSE
When is nervous system in adult configuration?
end of first trimester
End of Second Trimester Day 200
from dorsal root ganglion pseudounipolar cells have grown into dorsal horn and will synapse on GSA, GVE and GSE will grow out axons and join peripheral process with dorsal root and create spinal nerves, dorsal root ganglia from neural crest, all spinal nerves created
Bror Rexed’s Lamina System
lamina 1-6 are sensory, lamina 7-10 are motor, further segregation according to location of muscles they innervate (midline = proximal = axial, lateral = distal = appendicular)
According to Rexed’s Lamina System, motor columns closest to sensory regions innervate which muscles?
flexors
According to Rexed’s Lamina System, motor columns closest to anterior of the gray matter innervate which muscles?
extensors
Neuronal Clusters
clusters innervate a specific muscle, columns, if damaged the higher the lesion the less function will result, recruit small motor neurons first then larger
White Matter Areas of the Spinal Cord
axons of neurons ascending or descending, different physiological types of fibers based on diameter of fiber and conduction velocity of fibers
Type 1, 2, alpha-beta White Matter Fibers
large diameter and fast conducting fibers, all discriminative sensation (proprioception, 2-point differentiation), enter in from medial portion of dorsal side of spinal cord and synapse on GSA neurons
Type C and Delta White Matter Fibers
small diameter, crude sensation, lateral division of the dorsal horn, synapse on more superficial laminas of the cord (surgeons will cut to alleviate pain)
Fasciculus Gracilis and Fasciculus Cuneatus
somatotropic organization (more medial will be sacral, lateral is lumbar, etc.), dorsal columns get bigger at higher levels
Three Layers of Meninges
dura, arachnoid, pia
Dura Mater
outer layer of meninges, tough, made of fibroblasts and extremely strong tensile strength
Arachnoid Mater
middle layer, more fragile, made of fibroblast and collagen meshwork
Pia Mater
inner layer, only one cell layer thick, seen with magnification
Denticulate Ligaments
lateral extensions of the pia mater in between individual segments linking pia to dura
Where does the spinal cord end in adults?
L1/L2
How many pairs of spinal nerves are present?
there are 31 pairs of spinal nerves (I couldn’t just put 31 or excel was freaking out)
Cervical Region of Spine
C1-C2 is neck, C3-C5 is diaphragm, C5-T1 is upper extremity (brachial plexus)
Thoracic Region of Spine
upper half-thorax, lower half-abdominal
Lumbar Region of Spine
lower extremities
Sacral Region of Spine
bowel, bladder, and sexual function
Rami Communicans
brings visceral afferent (GVA) and efferent (GVE) to and from the sympathetic chain of ganglia
Four Choices when Entering the Sympathetic Chain
down-synapse right away and go to lower levels, back-synapse right away and via grey ramus communicans back to spinal nerve, up-higher levels before synapsing, viscera-splanchnic nerve to viscera
What components are in dorsal primary rami?
ALL FOUR REMEMBER?? GSA, GVA, GSE, GVE. Geez if I have to type it one more time..
Where are the expansions in the spinal cord?
upper thoracic and lumbar
Cervical Region of Spinal Cord Expansion
lateral horn-distal muscles are located laterally
Lumbar Region of Spinal Cord Expansion
lateral horn-distal muscles are located laterally
Arteries of the Spinal Cord
one anterior spinal artery (median sulcal artery off it), two posterior spinal arteries (vasocoronal between anterior and posterior)
Three Layers of Brain Stem Development
1st layer - motor fiber, 2nd layer - sensory fiber, 3rd layer - nuclear layer
1st Layer - Motor Fiber Layer
voluntary motor cell layers, millions of axons, descending, at base of medulla fibers split and 90% cross midline and terminate on opposite side of which they originate
2nd Layer - Sensory Fiber Layer
coming from dorsal columns and anterolateral columns, ascending, millions of axons, join together to travel to higher levels
3rd Layer - Nuclear Layer
collection of cells that are creating cranial nerves, each cell represents a nuclear group for one cranial nerve
Medullary Development
similar to spinal nerve development but roof plate does not fuse instead opens up to create fourth ventricle (still motor and sensory plates)
Gill Arches (branchial nerves)
1st arch 5th nerve (trigeminal), 2nd arch 7th nerve (facial), 3rd arch 9th nerve (glossopharyngeal), 4th arch 10th nerve (vagus)
Additional Components in Medulla
of course it still has GSA, GVA, GSE, and GVE but additionally Gil Arches, SVE, SVA, SSA
SVE
special visceral efferent column, associated with certain cranial nerves that are derived from the branchial arches
SVA
special visceral afferent column, associated with certain cranial nerves that are derived from the branchial arches
SSA
special somatic afferent column
Development of Metencephalon
pontine development (rhombic lip–>cerebellum), midbrain development (same as pons plus substantia nigra and red nucleus)
Substantia Nigra
in midbrain development, high melanin content, appear dark, these cells die in parkinson’s disease
Red Nucleus
posterior to substantia nigra, high in bilirubin, motor nucleus, non-volitional motor system, innervates shoulder and hip girdle (stability)
Motor Cell Columns
GSE, GVE, SVE
Sensory Cell Columns
GSA, GVA, SSA, SVA
