Nervous System Lecture Objectives Describe the anatomical and functional organization of the nervous system Describe the histologic features of neurons their processes and synapses Describe the histologic features and functions of glial cells ID: 910385
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Slide1
Nervous System
Kristine Krafts, M.D.
Slide2Nervous System Lecture ObjectivesDescribe the anatomical and functional organization of the nervous system.Describe the histologic features of neurons, their processes, and synapses.
Describe the histologic features and functions of glial cells.
Slide3More Nervous System Lecture ObjectivesDescribe myelin and its production in the central and peripheral nervous systems.Describe the histologic structure and distribution of the meninges.
Describe the blood-brain barrier.Describe the histologic features of nerve fibers in the peripheral nervous system.
Slide4Nervous System Lecture OutlineOrganization of the nervous systemCells of the nervous systemCentral nervous system
Slide5Nervous System Lecture OutlineOrganization of the nervous system
Slide6Organization of Nervous SystemCentral nervous system (CNS) = brain + spinal cordPeripheral nervous system (PNS) = peripheral nerves + nerve ganglia (groups of nerve cell bodies outside the CNS)
Peripheral nervous system has motor and sensory components.
Slide7Slide8Nervous System Lecture OutlineOrganization of the nervous systemCells of the nervous system
NeuronsGlial cells
Slide9Two Main Cell Types in Nerve TissueNeurons (nerve cells)Glial cellsAstrocytes
OligodendrocytesEpendymal cellsMicrogliaSchwann cells
Slide10Nervous System Lecture OutlineOrganization of the nervous systemCells of the nervous system
Neurons
Slide11Neurons
Slide12axon
cell body
dendrites
Cell body
maintains the cell; can receive synaptic input
Tons of
Nissl substance
(rough ER)
Multiple
dendrites
(receive impulses)
One
axon
(sends out impulses) – originates at “axon hillock”
Cytoskeleton contains neurofilaments (for structure) and microtubules (for transport along axons)
Nissl substance
Axon hillock
Slide13Neuron cell body
Large pale nucleus
Nucleolus
Nissl substance
Slide14Gorgeous, sexy
neuron and neuropil
Slide15Gorgeous, sexy
J. Crew shimmer net skirt
Slide16Gorgeous, sexy Louis Vuitton tulle skirt
Slide17Nervous System Lecture OutlineOrganization of the nervous systemCells of the nervous system
NeuronsGlial cells
Slide18Glial Cells10x more abundant than neurons in brainSupport and protect neurons
Five types, each with different functions:AstrocyteOligodendrocyteSchwann cellEpendymal cellMicroglial cell
Slide19Glial cell type
LocationMain functions
AstrocyteCNSProvides structural support, participates in blood-brain barrier
Oligodendrocyte
CNS
Makes myelin
Schwann cell
PNS
Makes myelin
Ependymal cell
CNS
Lines cavities of CNS
Microglial cell
CNS
Eats
up debris and dead cells
Location and Function of Glial Cells
Slide20Neuropil and an astrocyte
Slide21Astrocyte foot processes bind to capillaries and neurons
Slide22Oligodendrocytes are smaller and darker than astrocytes.
Slide23Oligodendrocytes produce myelin in the CNS.
Slide24Schwann Cells
Schwann cells produce myelin in the PNS.
Slide25Ependymal cells
Slide26Microglial cells
Slide27Nervous System Lecture OutlineOrganization of the nervous system
Cells of the nervous systemCentral nervous systemSpinal cordCerebrumCerebellumMeninges
Slide28Gross anatomy of brain
Slide29Slide30Gray Matter and White MatterGray matter contains neuron cell bodies, dendrites, unmyelinated axons, glial cells and synapses
White matter contains myelinated axons and oligodendrocytesBrain: gray matter outside (and way deep inside), white matter insideSpinal cord: white matter outside, gray matter inside
Slide31Cerebral CortexCerebral cortex (= gray matter of the cerebrum) has 6 poorly-defined layers.
Pyramidal neurons are the most abundant neurons in the cerebral cortex.
Slide32Note long dendrites of pyramidal neurons extending toward surface of cortex. This is a silver stain which really highlights neural cells.
Cerebral Cortex
Slide33Gray matter (outside) has 3 layers:Molecular layer. Outermost layer. Contains granular cell axons, Purkinje dendrites, and glial cells.
Purkinje cell layer. Middle layer. Contains large, prominent “Purkinje” neurons.
Granular layer. Innermost layer. Contains very small neurons.White matter is on the inside.
Cerebellum
Slide34Cerebellum: gray matter
Slide35MeningesProtective tissue layers surrounding brain and spinal cord.Dura mater (“tough mother”)
Outermost layer. Dense connective tissue.Arachnoid (“spider-like”)Middle layer. Two parts: one is in contact with dura mater. Other contains trabeculae (like spider legs) which connect arachnoid with pia.
Pia mater (“tender mother”)Innermost layer. Loose connective tissue tightly adherent to surface of brain/spinal cord.
Slide36Slide37Slide38At night, space around arteries opens, allowing CSF to flow in.
Brain waste material is dumped into veins and taken out like trash!
Glymphatic system
Slide39Blood-Brain BarrierPrevents passage of some drugs and toxins from blood into CNS tissueExists because capillaries in brain are less permeable than capillaries elsewhere.
Brain capillaries have tight (occluding) junctions between endothelial cells.Astrocyte foot processes surround capillaries and form part of barrier.
Slide40Blood-Brain
Barrier
1. Astrocyte foot processes
2. Endothelial cell
tight junctions
Slide41Spinal Cord Cross Section
White matter outside
Gray matter inside
Slide42Spinal Cord
Gray matter: neurons
and glial cells.
White matter: myelinated axons and oligodendrocytes.
Slide43Nervous System Lecture OutlineOrganization of the nervous systemCells of the nervous systemCentral nervous system