University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2024
Views:

331

Pages:

50
Author:

Dixie Summers

Peripheral Nerve NERVOUS TISSUE Ref code # 18 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. Ref code #2 NERVE IS LIKE EPITHELIUM ORIGIN OF NERVE IS ECTODERM LIKE EPIDERMIS (EPITHELIUM) OF SKIN Ref code # 5, 6 492 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 = Neurons are metabolically active cells Satellite cells Surrounding each cell body should be a variable number of nuclei of Satellite cells 492 Peripheral ganglion monkey Nissl substance 492 Ref code #6 440 Ganglion cell bodies in pancreas 29291 Bile ducts in monkey Ganglion cell body in cystic bile duct cystic bile duct vein 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. 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 Ref code #6 Organization of Peripheral Nerves Nerve fibers - axons invested by connective tissue Epineurium - surrounding entire nerve Perineurium - surrounding fascicles – constitutes the PNS blood barrier via tight junctions between fibroblasts Endoneurium - between individual nerve axons Ref code #6 Organization of Peripheral Nerves Ref code # 12 DEMO SLIDE BOX 78 . Dorsal root ganglion & nerve, cat. small ganglion and a cross-section of nerve Epineurium surrounding entire nerve Perineurium surrounding fascicles – Endoneurium between individual nerve axons Types of Nerves Ref code #7 HISTO0280 Bipolar neurons bipolar neurons of the inner ear Slide HISTO0280 at the left hand side of the cochlea on the bottom circle Ref code #7 152 Duodenum (small intestine) Nerve (Auerbach's plexus) circular and longitudinal smooth muscle layers Submucosal glands mucosa Gut lumen 152 Duodenum (small intestine) Auerbach's plexus, which can be found in between the circular and longitudinal smooth muscle layers Auerbach's plexus Nerve cell bodies epithelium 32409 Smooth muscle cells (Auerbach's plexus) Nerve cell bodies Meissner’s plexus cell bodies EM 10c: postganglionic neuronal cell body in an Auerbach’s plexus; 22,000x 1. Nissl substance 2. Neurosecretory vesicles SCHWANN CELLS MYELIN Ref code #6 NODE OF RANVIER 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 Ref code #6 193 440 Nerve in connective tissue of a salivary gland Perineurium 492 Nerve nodes of Ranvier SCHWANN CELL STRUCTURE / FUNCTION Ref code # 6, 12 Ref code # 7, 12 MYELINATION and SCHWANN CELLS 109 Skin hand monkey nerve Fibroblasts nerve Endoneurium Perineurium Nerve 105 Nerves in tissues/organs Nerves 109 105 Perineurium 196 Human spermatic cord with vessels and nerve Human spermatic cord UT 196 196 Ductus deferens Blood vessels Nerve Perineurium Nerve Perineurium EM 10d: Schwann cells and axons; 21,000x print 1. Microtubule 2. Myelinated coat around a myelinated axon 3. Schwann cell cytoplasm around an unmyelinated axon 4. Vesicle in axoplasm 5. 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 Use retrograde axonal transport to map brain Ref code # 5, 6 Motor end plates in skeletal muscle One nerve innervates several muscle cells Slide HISTO007 Histo 07 Skeletal muscle cells : 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 1. Synaptic cleft 2. Synaptic vesicles 3. Smooth muscle 136 monkey tongue Skeletal muscle fibers (cells) Muscle spindles Intrafusal muscle fibers inside the capsule 105 Fingertip, monkey - sweat glands and ducts among Pacinian corpuscles Pacinian corpuscles Skin hand monkey 109 Eccrine sweat glands Adipocytes Hypodermis Pacinian corpuscles Papillary layer Dermal papillae Epidermal peg Slide HIST0 29: Thick Skin (ventral surface of finger) Meissner’s corpuscles in dermal papillae Epidermis Epidermal peg Dermal papillae Dermis Meissner’s corpuscle is a mechanoreceptor Epidermis nerve ending for sensitivity to light touch; you would find more on your fingers because they are more sensitive to touch than your elbow. Histo 29 Meissner’s corpuscles Dermal papillae Slide HIST0 29 Slide 426: Renal artery and vein with nerves Smooth muscle cells, peripheral nerve fibers(axons) and bundles of collagen fibers Fibroblasts 109 : Skin, hand, monkey Peripheral nerve fibers (axons) Fibroblasts Smooth muscle cells Bundles of collagen fibers Fibroblast Slide 196: Spermatic cord Bundles of collagen fibers Peripheral nerve fibers White fat cells Nerve Smooth muscle cells 34460 Human spermatic cord with nerve toluidine blue Bundles of collagen fibers Endothelium Perineurium Peripheral nerve fibers Smooth muscle cells Nerve Fibroblasts Questions on nerves Which is not a distinguishing feature of the nervous system a. Comprise the central and peripheral nervous system. b. Individual peripheral nerves are found in limited places in the body. c. Individual neurons and clusters of neurons (called ganglia) are found in most organs d. a and b e. a, b, and c Which embryonic origin – tissue type(s) match(s)? a. Ectoderm – nerve b. Endoderm – muscle c. Mesoderm – nerve d. a and b e. a, b, and c

Peripheral Nerve

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