BIOM20002 Lecture Notes - Lecture 2: Action Potential, Schwann Cell, White Matter
CNS hard to access since it is surrounded by hard bone
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Nervous system comprises a central division and a peripheral division
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CNS is elongated
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The rostro-caudal "neuraxis" of quadrupeds is essentially horizontal, so "up" and "down"
directions are dorsal and ventral
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Front = anterior = ventral
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Back = posterior = dorsal
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Note when vertebrates stand upright the neuraxis bends
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The neuraxis is essentially vertical in humans but is rotated anteriorly at the rostral end
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Anatomical orientation
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Para-sagittal = parallel to the sagittal plane
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Coronal section: a front on cut
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Sectional images of the CNS may be obtained while the subject is laying down, so care is
needed in specifying the plane section
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Organisation of the nervous system
2 Nervous system 1
Monday, July 28, 2014
8:08 AM
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CNS: brain and spinal cord
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Includes a number of neuronal clusters (ganglia) at specific locations along these
peripheral nerves
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also contains cell bodies
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Peripheral nervous system (PNS): nerves connecting the central nervous system to the body
(the periphery) - 31 spinal nerves and 12 cranial nerves (primarily to head+neck)
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Nucleus: a cluster of neurons in CNS
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Ganglion: a cluster of intimately associated neuron cell bodies that form a swelling in the PNS
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The meninges are 3 layers of connective tissue, forming a thick leathery covering over the
brain and spinal cord. Made of collagen and fibroblasts, has its own blood supply
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All 3 meninges: dura mater, arachnoid mater and pia mater.
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Dura mater is actually two layers. Under this is the arachnoid membrane. Spider like
tendrils (connective tissue strands) run from arachnoid to the surface below.
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The subarachnoid space is filled with cerebro-spinal fluid (CSF)
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Pia mater is a single epithelial layer, lining even where the vessels go into the brain
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The meninges
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Document Summary
Cns hard to access since it is surrounded by hard bone. Nervous system comprises a central division and a peripheral division. The rostro-caudal neuraxis of quadrupeds is essentially horizontal, so up and down directions are dorsal and ventral. The neuraxis is essentially vertical in humans but is rotated anteriorly at the rostral end. Note when vertebrates stand upright the neuraxis bends. Sectional images of the cns may be obtained while the subject is laying down, so care is needed in specifying the plane section. Peripheral nervous system (pns): nerves connecting the central nervous system to the body (the periphery) - 31 spinal nerves and 12 cranial nerves (primarily to head+neck) Includes a number of neuronal clusters (ganglia) at specific locations along these peripheral nerves also contains cell bodies. Ganglion: a cluster of intimately associated neuron cell bodies that form a swelling in the pns.
