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Guillain-Barre Syndrome (GBS)

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Guillain-Barre Syndrome (GBS) Nervous tissue Anatomically Central nervous system (CNS) brain and spinal cord Peripheral nervous system (PNS) - cranial, spinal, and peripheral nerves - ganglia: nerve cell bodies outside the CNS Major cell types Neuron: nerve cell Supporting / Glial cells - Schwann cells, satellite cells (in PNS) - glia/neuroglia (in CNS) Neurone / Neuron Cell body Nucleus Cytoplasm (perikaryon) Process Axon Dendrites Axons (nerve fibers) Axon hillock Terminal boutons Dorsal root ganglia (DRG) nucleus ganglion/ganglia DRG neurons Basic neuron types Multipolar neuron Multiple dendrites Single axons Types: Interneurons Motor neurons Sympathetic neurons Bipolar neuron Single dendrite Single axon Types: Receptor neurons Vision Smell Balance Pseudo-unipolar neuron peripheral Single axon (Stem process) with stem 2 branches: Central process to spinal cord Peripheral process to terminal tissues (muscle, joints, skin et al) functionally: dendrite structurally: axon Type: Dorsal root ganglia (DRG neuron) central Pseudo-unipolar neuron Neuron: ultrastructure Rough endoplamic reticulum (rER) Nissl substance Cytoskeleton Microtubule Intermediate filaments: Neurofilaments Microfilaments: Actin Specialization of neuron/axon Cytoskeleton Axonal transport Neuron: ultrastructure rER: rough ER M: mitochondria L: lysosome G: Golgi Microscopic methods H & E (Hematoxylin and eosin) Nissl method Heavy metal impregnation Golgi, Cajal Thick sections / Spread preparations gold, silver: deposited in microtubules / neurofilaments Immunohistochemistry Microscopic methods: H & E Microscopic methods: Nissl method Nissl substance: RNA in neuronal cell body and dendrite Microscopic methods: Heavy metal impregnation Spread preparation Au-impregnation Microscopic methods: Heavy metal impregnation (Purkinje cell of cerebellum) Thick section Ag-impregnation Au + counter stain Myelinated / non-mylinated nerves Diameter: related to nerve conduction Myelination: myelin sheaths (saltatory conduction) Cells responsible for myelination Schwann cells Oligodendrocytes Non-myelinated nerve fibers Myelination Major dense line Intraperiod line Myelinated nerve fibers Major dense line Intraperiod line Node of Ranvier Node of Ranvier Schmidt-Lanterman incisures Myelin compaction Non-compact myelin Node of Ranvier (paranodal regions) Schmidt-Lanterman incisure (cleft) Compact myelin Between nodes of Ranvier (internodal regions) Schmidt-Lanterman incisures Synapse: General organization Synapse (terminal bouton) Presynaptic components Pre-synaptic membrane Synaptic vesicles (neurotransmitters): active zone Synaptic cleft Postsynaptic components Post-synaptic membrane (receptors for transmitters) Neurons / Effector cells Synapse Motor end plates Gold method Histochemistry of Ach-esterase Motor end plates (Neuromuscular junctions) Synaptic cleft Junctional folds Nerve fibers and connective tissue Epineurium Perineurium Endoneurium Peripheral nervous tissues Organization Epineurium Perineurium Endoneurium Processing of tissues Paraffin-embedded Epon-embedded, osmium- fixed F: fascicle; E: epineurium; P: perineurium A (axon); AT (adipose tissue); BNF (bundle of nerve fibers); BV (blood vessel); C (capillary); Epn (epineurium); F (fibroblast); M (myelin); NI (neurilemma); Pn (perineurium);SS (Schwann cell nucleus) Peripheral nervous tissues P: perineurium S: Schwann cell; F: fibroblast Epn (epineurium); M (myelin); N (Schwann cell nucleus); NF (nerve fiber); NI (neurilemma); NR (node of Ranvier) Peripheral nervous tissues M: myelinated fiber N: non-myelinated fiber S: Schwann cell nuclei F: nuclei of fibroblast Demyelination (segmental) demyelination: teased fiber preparation absence of myelin sheaths in adjacent internode impaired saltatory conduction Dorsal root ganglion (Spinal ganglion) Satellite cells Sympathetic ganglion multipolar eccentric nuclei lipofuscin granules fewer satellite cells Sensory receptors Functional classification Exteroceptors: for thermal, pain etc Proprioceptors: in skeletal system Interoceptors: visceral organs Morphological classification Simple: Free nerve endings Compound (Encapsulated): Pacinian corpuscle, Meissner’s corpuscle etc Free nerve endings Epidermis Dermis Meissner’s corpuscles Encapsulated nerve endings in dermal papilla for touch Pacician corpuscles Lamellated sensory nerve endings with a capsule in subcutaneous tissue / hypodermis for vibratory stimuli Muscle spindles Skeletal muscles Extrafusal fibers Intrafusal fibers Nuclear bag fibers Nuclear chain fibers Sensory receptors around intrafusal fibers Annulospiral endings: in central non-striated portion Flower-spray ending: in striated portion Muscle spindles N: bundle of nerve fibers C: capsule enclosing intrafusal fibers Review of PNS Neurons Classification; Organization Myelin Compact myelin, node of Ranvier Sensory receptors Types vs Functions .
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