Medical School Histology Basics Peripheral Nerve
VIBS 289 lab Larry Johnson Texas A&M University NERVOUS TISSUE FUNCTIONS: SPECIALIZED FOR THE TRANSMISSION, RECEPTION,
AND INTEGRATION OF ELECTRICAL IMPULSES DISTINGUISHING FEATURES: NEURONS VERY LARGE EXCITABLE CELLS WITH LONG PROCESSES CALLED AXONS AND DENDRITES.THE AXONS MAKE CONTACT WITH OTHER NEURONS OR MUSCLE CELLS AT A SPECIALIZATION CALLED A SYNAPSE WHERE THE IMPULSES ARE EITHER ELECTRICALLY OR CHEMICALLY TRANSMITTED TO OTHER NEURONS OR VARIOUS TARGET CELLS (e.g., MUSCLE).OTHERS SECRETE HORMONES. NERVE ISLIKEEPITHELIUMORIGIN OF NERVE ISECTODERMLIKE EPIDERMIS(EPITHELIUM) OF SKIN 492 Peripheral ganglion monkey
Myelinated axons DEMO SLIDE BOX 76 . Ganglia, dog.
Nissl bodies = cytoplasm for coarse aggregates of basophilic substance = Rough Endoplasmic Reticulum and Polysomes Nucleus contains a large, prominent nucleolus and an abundant amount of euchromatin Satellite cells Surrounding each cell body should be a variable number of nuclei of Satellite cells = Neurons are metabolically active cells 492 Peripheral ganglion monkey Nissl substance 440 Ganglion cell bodies in pancreas 29291 Bile ducts in monkey Ganglion cell body in cystic bile duct vein DEMO SLIDE BOX 78. Dorsal root ganglion & nerve, cat
DEMO SLIDE BOX 78 . Dorsal root ganglion & nerve, cat. small ganglion and a cross-section of nerve DEMO SLIDE BOX 78. Dorsal root ganglion & nerve, cat
DEMO SLIDE BOX 78. Dorsal root ganglion & nerve, cat. small ganglion and a cross-section of nerve dark dots (these are the axons) surrounded by white circles (myelin sheath) Remember Connective Tissue Layers of Skeletal Muscle
Epimysium, Perimysium, and Endomysium Organization of Peripheral Nerves
Nerve fibers - axons invested by connective tissue Epineurum - surrounding entire nerve Perineurum - surrounding fascicles constitutes the PNS blood barrier via tight junctionsbetween fibroblasts Endoneurum - between individual nerve axons Organization of Peripheral Nerves DEMO SLIDE BOX 78. Dorsal root ganglion & nerve, cat
DEMO SLIDE BOX 78 . Dorsal root ganglion & nerve, cat. small ganglion and a cross-section of nerve Epineurum - surrounding entire nerve Perineurum - surrounding fascicles Endoneurum - between individual nerve axons Types of Nerves bipolar neurons of the inner ear Slide HISTO0280 at the left hand side of the cochlea on the bottom circle HISTO0280 Bipolar neurons Duodenum (small intestine)
152 Nerve (Auerbach's plexus) circular and longitudinal smooth muscle layers Submucosal glands mucosa Gut lumen Duodenum (small intestine)
152 Auerbach's plexus, which can be found in between the circular and longitudinal smooth muscle layers Auerbach's plexus Nerve cell bodies 32409 Smooth muscle cells (Auerbach's plexus)Nerve cell bodies
epithelium Smooth muscle cells Meissners plexus cell bodies 32409 (Auerbach's plexus)Nerve cell bodies EM 10c: postganglionic neuronal cell body in an Auerbachs plexus; 22,000x
Nissl substance Neurosecretory vesicles SCHWANN CELLSMYELIN NODE OF RANVIER DEMO SLIDE BOX 78. Dorsal root ganglion & nerve, cat
DEMO SLIDE BOX 78 . Dorsal root ganglion & nerve, cat. small ganglion and a cross-section of nerve axons, myelin sheath, node of Ranvier 492 perineurium Schwann cell nucleus Peripheral nerve, monkey nodes of Ranvier
193 Peripheral nerve, monkey nodes of Ranvier 440 Nerve in connective tissue of a salivary gland Perineurum 492 Nerve nodes of Ranvier SCHWANN CELL STRUCTURE / FUNCTION MYELINATION and SCHWANN CELLS 109 Skin hand monkey nerve Fibroblasts nerve Endoneurum Perineurum Nerves in tissues/organs
105 Nerves in tissues/organs Nerves 109 105 Perineurum 196 Human spermatic cord with vessels and nerve 196 spermatic cord UT 196 Nerve Perineurum Nerve Perineurum EM 10d: Schwann cells and axons; 21,000x print Microtubule
Myelinated coat around a myelinated axon Schwann cell cytoplasm around an unmyelinated axon Vesicle in axoplasm Nucleus of a Schwann cell NEURONAL STRUCTURE / FUNCTION
Axonal transport Anterograde - toward terminal - kinesin Retrograde - toward cell body - dynein Tetanus toxin Neurotropic viruses (herpes and rabies) use path to get to cell body in CNS Neuronal Structure / Function Neuronal Structure/Function : Skeletal muscle motor end plates Motor end plates in skeletal muscle
One nerve innervates several muscle cells Slide HISTO007 Histo 07 Skeletal musclecells : Skeletal muscle motor end plates Summary of the Physiological Events at the Synapse
Arrival of action potential at axon terminal Opening Ca++ channels Influx of Ca++ into axon terminal Exocytosis of neurotransmitter Diffusion of neurotransmitter across synaptic cleft Binding of neurotransmitter to receptors on target cell Opening of Na+ channels causing depolarization of target cell Removal of neurotransmitter EM 10e: Nerve terminal on smooth muscle; 41,000x print
Synaptic cleft Synaptic vesicles Smooth muscle 136 monkey tongue Skeletal muscle fibers (cells) Muscle spindles
Intrafusal muscle fibers inside the capsule Fingertip, monkey - sweat glands and ducts among Pacinian corpuscles
105 Fingertip, monkey - sweat glandsand ducts among Pacinian corpuscles Pacinian corpuscles Skin hand monkey Hypodermis 109
url at Adipocytes Eccrine sweat glands Hypodermis Pacinian corpuscles Dermal papillae Epidermal peg Papillary layer Slide HIST0 29: Thick Skin (ventral surface of finger)
Meissners corpuscles in dermal papillae Meissners corpuscle is a mechanoreceptor nerve ending for sensitivity to light touch; you would find more on your fingers because they are more sensitive to touch than your elbow. Epidermis Epidermis Epidermal peg Dermal papillae Dermis Histo 29 Meissners corpuscles Slide HIST0 29 Slide 426: Renal artery and vein with nerves
Smooth muscle cells, peripheral nerve fibers and bundles of collagen fibers Fibroblasts 109 : Skin, hand, monkey Peripheral nerve fibers Fibroblasts
Smooth muscle cells Bundles of collagen fibers Fibroblast Slide 196: Spermatic cord Peripheral nerve fibers Smooth muscle cells
Bundles of collagen fibers White fat cells Nerve Smooth muscle cells 34460 Human spermatic cord with nerve toluidine blue
Bundles of collagen fibers Endothelium Perineurum Peripheral nerve fibers Nerve Smooth muscle cells Fibroblasts Questions on nerves Which is not a distinguishing feature of the nervous system Comprise the central and peripheral nervous system. Individual peripheral nerves are found in limited places in the body. Individual neurons and clusters of neurons (called ganglia) are found in most organs a and b a, b, and c Which embryonic origin tissue type(s) match(s)? Ectoderm nerve Endoderm muscle Mesoderm nerve a and b a, b, and c Many illustrations in these VIBS Histology YouTube videos were modified from the following books and sources:Many thanks to original sources! Bruce Alberts, et al Molecular Biology of the Cell.Garland Publishing, Inc., New York, NY. Bruce Alberts, et al Molecular Biology of the Cell.Garland Publishing, Inc., New York, NY. William J. Banks, Applied Veterinary Histology.Williams and Wilkins, Los Angeles, CA. Hans Elias, et al Histology and Human Microanatomy.John Wiley and Sons, New York, NY. Don W. Fawcett Bloom and Fawcett.A textbook of histology.W. B. Saunders Company, Philadelphia, PA. Don W. Fawcett Bloom and Fawcett.A textbook of histology.Chapman and Hall, New York, NY. Arthur W. Ham and David H. Cormack Histology.J. S. Lippincott Company, Philadelphia, PA. Luis C. Junqueira, et al Basic Histology.Lange Medical Publications, Los Altos, CA. L. Carlos Junqueira, et al Basic Histology.Appleton and Lange, Norwalk, CT. L.L. Langley, et al Dynamic Anatomy and Physiology.McGraw-Hill Book Company, New York, NY. W.W. Tuttle and Byron A. Schottelius Textbook of Physiology.The C. V. Mosby Company, St. Louis, MO. Leon Weiss Histology Cell and Tissue Biology.Elsevier Biomedical, New York, NY. Leon Weiss and Roy O. Greep Histology.McGraw-Hill Book Company, New York, NY. Nature (http://www.nature.com), Vol. 414:88,2001. Arthur C. Guyton,1971.Textbook of Medical Physiology W.B. Saunders company, Philadelphia, PA WW Tuttle and BA Schottelius Textbook of Physiology C.V. Mosby Co. A.L. Mescher Junqueiras Basis Histology text and atlas, 13th ed. McGraw Big Bend National Park, TX The end of