DOCSLIB.ORG

The Ependyma of the Cat Central Canal, with Particular Reference to Its Mitochondria-Containing Bulbs

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Ependyma of the Cat Central Canal, with Particular Reference to Its Mitochondria-Containing Bulbs Scanning Electron Microscopy Volume 1985 Number 1 1985 Article 24 10-5-1984 The Ependyma of the Cat Central Canal, with Particular Reference to its Mitochondria-Containing Bulbs K. Rascher University of the Saarland K. H. Booz University of the Saarland A. C. Nacimiento University of the Saarland E. Donauer University of the Saarland Follow this and additional works at: https://digitalcommons.usu.edu/electron Part of the Biology Commons Recommended Citation Rascher, K.; Booz, K. H.; Nacimiento, A. C.; and Donauer, E. (1984) "The Ependyma of the Cat Central Canal, with Particular Reference to its Mitochondria-Containing Bulbs," Scanning Electron Microscopy: Vol. 1985 : No. 1 , Article 24. Available at: https://digitalcommons.usu.edu/electron/vol1985/iss1/24 This Article is brought to you for free and open access by the Western Dairy Center at DigitalCommons@USU. It has been accepted for inclusion in Scanning Electron Microscopy by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. SCANNING ELECTRON MICROSCOPY/ 1985 / I (Pa ge l 231-2 38) 0586- 5581/85$1 . 00+. 0S SEM I nc.., AMF O'Ha11.e (Chi c.ago), IL 6066 6 USA THE EPENDYMA OF THE CAT CENTRAL CANAL, WITH PARTICULAR REFERENCE TO ITS MITOCHONDRIA-CONTAINING BULBS K. Rascher*, K.H. Booz*, A.C. Nacimiento** and E. Donauer*** *Department of Anatomy, **Neurosurgery Research Laboratory, ***Department of Neurosurgery, University of the Saarland, 6650 Homburg, Federal Republic of Germany (Paper received March 20 1984, Completed manuscript rec e ived October 5 1984) Introduction Abstract Most scanning electron microscope The ultrastructure of the ependyma studies of the ependyma have dealt with in the central canal of adult cats was the lining of the brain ventricles (see examined in both the scanning and the extensive literature in Leonhardt 1980 transmission electron microscopes (SEM and Low 1982). The ependyma of the cen­ and TEM). tral canal, however, has only rarely The same morphological details were been subjected to intensive ultrastruc­ seen in the ependyma of the central can­ tural examination (Leonhardt 1976). One al as have so frequently been described of the reasons for this relative lackof in the ependyma of the brain ventricular information on the central canal may be system, for example bundles of cilia, that its free surfaces are considerably single cilia, microvilli and occasional more difficult to expose for observation small cytoplasmic protrusions. The in the SEM than are the surfaces of the supraependymal cells and supraependymal ventricles. Another may be that the cen­ nerve fibers found in the central canal tral canal has not very often been the also resembled those seen in the ven­ subject of experimental and/or patholo­ tricular system. gical research (Hall et al. 1975). The The most striking feature of the present study was undertaken in connec­ canal ependyma were the large, spherical tion with an ongoing investi gation of bodies containing numerous mitochondria. the alterations in the c e ntral canal They are therefore called mitochondria­ caused by experimentall y induced hydro­ containing bulbs. In sections the bulbs cephalus in adult cats. were seen to be connected by long, The ependyma of the cat centralcan­ slender stalks to neurons in subependy­ al has many features in common with that mal position. In some respects the of the ventricles of higher vertebrates mitochondria-containing bulbs resemble and is quite similar to that of the rab­ the processes of cerebrospinal fluid­ bit central canal (Leonhardt 1976) but contacting neurons. does differ in several respects fromthat of the rat canal (Nakayama and Kohno 1974) Both SEM and TEM revealed that the catpo­ ssesses spherical supraependymal struc­ tures containing numerous mitochondria. They could be identified as the processes of neurons lying in subependymalposition. These neurons are therefore cerebrospi­ nal fluid-contacting neurons. Their sim­ ilarity to the well-known cerebrospinal fluid (CSF)-contacting neurons of lower vertebrates (Vigh and Vigh-Teichmann 1971) KEY WORDS: Ependyma, Spinal Cord Central Canal, Mitochondria-containing Processes, may give a clue to their possible Cat, Scanning Electron Microscopy function. Materials and Methods *Address for correspondence: Adult cats were deeply anesthetized K. Rascher, Department of Anatomy, with nembutal (0. 35g/kg) and artificially University of the Saarland, 6650 Homburg, respirated before being transcardially Federal Republic of Germany perfused with a buffered mixture of 1% Phone No. 06841/166102 glutaraldehyde and 1% paraformaldehyde. The animals, which weighed between 2.3 231 Rascher K, Booz KH, Nacimiento AC et al. Figure 1. Semithin secti.onof the central canal and its immediate surroundings in the cervical intumescence. L = lumen of the canal; E = ependyma; arrow= mito­ chondria-containing bulb. Figure 2. Semi thin section of the central canal in the upper lumbar region. L = lumen of the canal; E = ependyma; arrow= mitochondria-containing bulb. Figure 3. Overview of the vent ral aspect and 3.0 kilograms, received 1 lit er of of the central canal split longitudinall~ warm perfusion fixative per kilogram Mid-thoracic region. C = heavily ciliated body weight. The spinal cord was removed ependyma; arrow= mitochondria-containing and postfixed in fresh cold fixative at bulbs; B = blood vesse l with well-devel­ least overnight before being dissected oped perivascular space . into tissue blocks for scanning andtrans­ Figure 4. Cl oseup of the cut edge of the mission electron microscopy. The samples ependyma illustratin g the synchronous for SEM were split to expose the ependyma beat of the kinocilia. Caudalto the left. and subsequently postfixed in a buffered solution of 1% osmium t et roxide. The y Semithin and thin sections were cut on a were then rinsed in 2.4 % NaCl and dehy­ Reichert microtome with g la ss knives; drated in an ascending series ofmethanol. the thin sections were viewed in a Zeiss The tissue was transferred to Freon 11 EM 9 at 60 kV. and critical point dried in Freon 13 (Co­ Results hen et al. 1968) in a Polaron apparatus. The specimens were coated with gold in a The central canal of the cat va ries Balzers sputt ering chamber and examined in shape depending upon the level of the in a Cambridge Stereosca n S4 at 20 kV. spinal cord examined. In the upper cer­ The tissue samples for TEM were rin­ vical and in the sacral regions it is a sed in phosphate buffer before being post­ narrow slit with the lateral walls almost fixed in 2% osmium tetroxide. The y were touching; in the thoracic segments it is then rinsed again in buffer. The samples more or less round whereas in both the were dehydrated in isopropanol, trans­ cervical and the lumbar intumescences it ferred to propylene oxide and embedded is again slit-like but with the dorsal in an epoxy resin (ERL 4206, Spurr 1969). 232 The ependy.ma of the cat central canal 7 • pr Figure 5. Detail of the surface of the less densely ciliated area along the dorsal cervical midline. Note the multi­ tude of microvilli on the tall protru­ sions of the apical poles of the cells. B = mitochondria-containing bulb; S smooth profile. and ventral surfaces closely apposed (compare Figures 1 and 2). The shape of the canal may be slightly altered by large blood vessels with a well-deveJoped perivascular space which penetrate into the subependymal tissue (Fig. 3). The SEM reveals that the ependyma of the can­ al has several ultrastructural features which are also characteristic of the ven­ tricular ependyma. It is fairly densely ciliated throughout (Fig. 3). The cilia are grouped in bundles so close together that the cell surfaces of the ependymo­ Figure 6. Thin section of area as in fig­ cytes can only rarely be seen. The cilia ure 5. P apical protrusion with micro­ are bent in such a manner that their beat villi; C = basal bodies of a bundle of is apparently from rostral to caudal cilia; N = nuclei of ependymocytes; arrow= (Fig. 4). The carpet of cilia becomes contacts between ependymocytes. sparser along the midline both dorsally Figure 7. Apical parts of ependymocytes and ventrally. These areas bearing fewer in ventro-median (cervical) position in­ cilia are quite narrow in the upper cer­ dicating the well-developed contacts and vical segments, broad in both intumes­ interdigitations between the cells. cences and almost invisible in thoracic levels. The less densely ciliated areas microvilli were taller along the dorsal show a multitude of microvilli on the cell aspect than along the ventral. Another apical poles. For the most part the lat­ feature which distinguished the ventral ter protrude markedly into the lumen of from the dorsal ependyma of the midlines the canal, extending their microvilli in were the cell contacts. Those of the dor­ all directions, thus giving the entire sal aspect were generally straight and surface a mossy appearance (Fig. 5). In consisted of only a few short desmosome­ thin sections the protrusions of the api­ like contacts and an occasionalapically cal poles were seen to contain a fine located gap junction. The lateral cell granular matrix and occasional microfila­ borders of the ventrally positioned epen­ ments but no larger organelles (Fig. 6). dymocytes, however, had highly developed The scanned specimens did not reveal junctional complexes with long series of any major ultrastructural differences be­ desmosome-like contacts. These cells in­ tween the dorsal and ventral surfaces of terdigitated with one another giving the the canal, but thin sectionsconsistently membranes a tortuous course (compare showed that the protrusions bearing Figures 6 and 7). 233 Rascher K, Booz KH, Nacimiento AC et al. - . "': ... ~ - .• . · - F ~ :'i , ,. J:.--' . ~:·,~""'t - ~- . & f t 1t· ;f .,. '.', ~ ! ; .... :~ ~ T ,. •~- r ·~ , . ..··~_:. / ~\; . ~ ·, ... '10 . £1:""ftt~::a! ~~"' ..· •. Figure 8. Several mitochondria-containing bulbs in ventral aspect of cervical can­ al.
Load more

Recommended publications
  • Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
    Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal.
    [Show full text]
  • Deconstructing Spinal Interneurons, One Cell Type at a Time Mariano Ignacio Gabitto
    Deconstructing spinal interneurons, one cell type at a time Mariano Ignacio Gabitto Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy under the Executive Committee of the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2016 © 2016 Mariano Ignacio Gabitto All rights reserved ABSTRACT Deconstructing spinal interneurons, one cell type at a time Mariano Ignacio Gabitto Abstract Documenting the extent of cellular diversity is a critical step in defining the functional organization of the nervous system. In this context, we sought to develop statistical methods capable of revealing underlying cellular diversity given incomplete data sampling - a common problem in biological systems, where complete descriptions of cellular characteristics are rarely available. We devised a sparse Bayesian framework that infers cell type diversity from partial or incomplete transcription factor expression data. This framework appropriately handles estimation uncertainty, can incorporate multiple cellular characteristics, and can be used to optimize experimental design. We applied this framework to characterize a cardinal inhibitory population in the spinal cord. Animals generate movement by engaging spinal circuits that direct precise sequences of muscle contraction, but the identity and organizational logic of local interneurons that lie at the core of these circuits remain unresolved. By using our Sparse Bayesian approach, we showed that V1 interneurons, a major inhibitory population that controls motor output, fractionate into diverse subsets on the basis of the expression of nineteen transcription factors. Transcriptionally defined subsets exhibit highly structured spatial distributions with mediolateral and dorsoventral positional biases. These distinctions in settling position are largely predictive of patterns of input from sensory and motor neurons, arguing that settling position is a determinant of inhibitory microcircuit organization.
    [Show full text]
  • Delineating the Diversity of Spinal Interneurons in Locomotor Circuits
    The Journal of Neuroscience, November 8, 2017 • 37(45):10835–10841 • 10835 Mini-Symposium Delineating the Diversity of Spinal Interneurons in Locomotor Circuits Simon Gosgnach,1 Jay B. Bikoff,2 XKimberly J. Dougherty,3 Abdeljabbar El Manira,4 XGuillermo M. Lanuza,5 and Ying Zhang6 1Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada, 2Department of Neuroscience, Columbia University, New York, New York 10032, 3Department of Neurobiology and Anatomy, Drexel University, Philadelphia, Pennsylvania 19129, 4Department of Neuroscience, Karolinska Institutet, Stockholm SE-171 77, Sweden, 5Department of Developmental Neurobiology, Fundacion Instituto Leloir, Buenos Aires C1405BWE, Argentina, and 6Department of Medical Neuroscience, Dalhousie University. Halifax, Nova Scotia B3H 4R2, Canada Locomotion is common to all animals and is essential for survival. Neural circuits located in the spinal cord have been shown to be necessary and sufficient for the generation and control of the basic locomotor rhythm by activating muscles on either side of the body in a specific sequence. Activity in these neural circuits determines the speed, gait pattern, and direction of movement, so the specific locomotor pattern generated relies on the diversity of the neurons within spinal locomotor circuits. Here, we review findings demon- strating that developmental genetics can be used to identify populations of neurons that comprise these circuits and focus on recent work indicating that many of these populations can be further subdivided
    [Show full text]
  • The Spinal Cord Is a Nerve Column That Passes Downward from Brain Into the Vertebral Canal
    The spinal cord is a nerve column that passes downward from brain into the vertebral canal. Recall that it is part of the CNS. Spinal nerves extend to/from the spinal cord and are part of the PNS. Length = about 17 inches Start = foramen magnum End = tapers to point (conus medullaris) st nd and terminates 1 –2 lumbar (L1-L2) vertebra Contains 31 segments à gives rise to 31 pairs of spinal nerves Note cervical and lumbar enlargements. cauda equina (“horse’s tail”) –collection of spinal nerves at inferior end of vertebral column (nerves coming off end of spinal cord) Meninges- cushion and protected by same 3 layers as brain. Extend past end of cord into vertebral canal à spinal tap because no cord A cross-section of the spinal cord resembles a butterfly with its wings outspread (gray matter) surrounded by white matter. GRAY MATTER or “butterfly” = bundles of cell bodies Posterior (dorsal) horns=association or interneurons (incoming somatosensory information) Lateral horns=autonomic neurons Anterior (ventral) horns=cell bodies of motor neurons Central canal-found within gray matter and filled with CSF White Matter: 3 Regions: Posterior (dorsal) white column or funiculi – contains only ASCENDING tracts à sensory only Lateral white column or funiculi – both ascending and descending tracts à sensory and motor Anterior (ventral) white column or funiculi – both ascending and descending tracts à sensory and motor All nerve tracts made of mylinated axons with same destination and function Associated Structures: Dorsal Roots = made
    [Show full text]
  • Spinal Cord Organization
    Lecture 4 Spinal Cord Organization The spinal cord . Afferent tract • connects with spinal nerves, through afferent BRAIN neuron & efferent axons in spinal roots; reflex receptor interneuron • communicates with the brain, by means of cell ascending and descending pathways that body form tracts in spinal white matter; and white matter muscle • gives rise to spinal reflexes, pre-determined gray matter Efferent neuron by interneuronal circuits. Spinal Cord Section Gross anatomy of the spinal cord: The spinal cord is a cylinder of CNS. The spinal cord exhibits subtle cervical and lumbar (lumbosacral) enlargements produced by extra neurons in segments that innervate limbs. The region of spinal cord caudal to the lumbar enlargement is conus medullaris. Caudal to this, a terminal filament of (nonfunctional) glial tissue extends into the tail. terminal filament lumbar enlargement conus medullaris cervical enlargement A spinal cord segment = a portion of spinal cord that spinal ganglion gives rise to a pair (right & left) of spinal nerves. Each spinal dorsal nerve is attached to the spinal cord by means of dorsal and spinal ventral roots composed of rootlets. Spinal segments, spinal root (rootlets) nerve roots, and spinal nerves are all identified numerically by th region, e.g., 6 cervical (C6) spinal segment. ventral Sacral and caudal spinal roots (surrounding the conus root medullaris and terminal filament and streaming caudally to (rootlets) reach corresponding intervertebral foramina) collectively constitute the cauda equina. Both the spinal cord (CNS) and spinal roots (PNS) are enveloped by meninges within the vertebral canal. Spinal nerves (which are formed in intervertebral foramina) are covered by connective tissue (epineurium, perineurium, & endoneurium) rather than meninges.
    [Show full text]
  • Differences in Neural Stem Cell Identity and Differentiation Capacity Drive Divergent Regenerative Outcomes in Lizards and Salamanders
    Differences in neural stem cell identity and differentiation capacity drive divergent regenerative outcomes in lizards and salamanders Aaron X. Suna,b,c, Ricardo Londonoa, Megan L. Hudnalla, Rocky S. Tuana,c, and Thomas P. Lozitoa,1 aCenter for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219; bMedical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213; and cDepartment of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213 Edited by Robb Krumlauf, Stowers Institute for Medical Research, Kansas City, MO, and approved July 24, 2018 (received for review March 2, 2018) While lizards and salamanders both exhibit the ability to re- lizard tail regenerate (20), and the key to understanding this generate amputated tails, the outcomes achieved by each are unique arrangement of tissues is in identifying the patterning markedly different. Salamanders, such as Ambystoma mexicanum, signals involved. regenerate nearly identical copies of original tails. Regenerated lizard Both lizards and salamanders follow similar mechanisms of tails, however, exhibit important morphological differences compared tail development during embryonic development. The embryonic with originals. Some of these differences concern dorsoventral pat- spinal cord and surrounding structures are formed and patterned terning of regenerated skeletal and spinal cord tissues; regenerated by the neural tube (21, 22). The neural tube exhibits distinct + salamander tail tissues exhibit dorsoventral patterning, while re- domains: roof plate (characterized by expression of Pax7 , BMP- + + + grown lizard tissues do not. Additionally, regenerated lizard tails lack 2 , and Sox10 among others), lateral domain (Pax6 ), and floor + + characteristically roof plate-associated structures, such as dorsal root plate (Shh , FoxA2 ).
    [Show full text]
  • Reaction of Ependymal Cells to Spinal Cord Injury: a Potential Role for Oncostatin Pathway and Microglial Cells
    bioRxiv preprint doi: https://doi.org/10.1101/2021.02.12.428106; this version posted February 13, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Reaction of ependymal cells to spinal cord injury: a potential role for oncostatin pathway and microglial cells *1 *1 *1 2 2 1 R. Chevreau ​ , H Ghazale ,​ C Ripoll ,​ C Chalfouh ,​ Q Delarue ,​ A.L. Hemonnot ,​ H 1 ​ 3 ​ 4 ​ 5 ​ *2 ​ *1 ​ Hirbec ,​ S Wahane ,​ F Perrin ,​ H Noristani ,​ N Guerout ,​ JP Hugnot ​ ​ ​ ​ ​ ​ *equal contribution, listed in alphabetic order 1 Université de Montpellier, INSERM CNRS IGF, France ​ 2 Université de Rouen, France ​ 3 Departments of Neurobiology and Neurosurgery, David Geffen School of Medicine, ​ University of California, Los Angeles, Los Angeles CA 90095-1763, USA. 4 University of Montpellier, INSERM MMDN France ​ 5 Shriners Hospitals Pediatric Research Center, NY, USA ​ Abstract Ependymal cells with stem cell properties reside in the adult spinal cord around the central canal. They rapidly activate and proliferate after spinal cord injury, constituting a source of new cells. They produce neurons and glial cells in lower vertebrates but they mainly generate glial cells in mammals. The mechanisms underlying their activation and their glial-biased differentiation in mammals remain ill-defined. This represents an obstacle to control these cells. We addressed this issue using RNA profiling of ependymal cells before and after injury. We found that these cells activate STAT3 and ERK/MAPK signaling during injury and downregulate cilia-associated genes and FOXJ1, a central transcription factor in ciliogenesis.
    [Show full text]
  • Neuropathology of the Brainstem and Spinal Cord in End Stage Rheumatoid Arthritis: Implications for Treatment
    Annals of the Rheumatic Diseases 1993; 52: 629-637 629 EXTENDED REPORTS Ann Rheum Dis: first published as 10.1136/ard.52.9.629 on 1 September 1993. Downloaded from Neuropathology of the brainstem and spinal cord in end stage rheumatoid arthritis: implications for treatment Fraser C Henderson, Jennian F Geddes, H Alan Crockard Abstract Methods Objective-To study the detailed histo- This study includes nine patients with sero- pathological changes in the brainstem and positive rheumatoid arthritis (eight women, spinal cord in nine patients with severe one man) from our ongoing prospective study, end stage rheumatoid arthritis, all with who underwent necropsy at the National clinical myelopathy and craniocervical Hospitals for Neurology and Neurosurgery compression. between 1987 and 1991. All patients were Methods-At necropsy the sites of bony evaluated by rheumatologists, a neurosurgeon pathology were related exactly to cord (HAC), two neuroradiologists, a physio- segments and histological changes, and therapist, and a research nurse. The clinical correlated with clinical and radiological assessment included a full neurological exam- findings. ination and a detailed questionnaire about Results-Cranial nerve and brainstem neurological symptoms. In addition, all pathology was rare. In addition to the patients were graded according to Ranawat obvious craniocervical compression, there et al'9 and Steinbrocker et al.20 The radiological were widespread subaxial changes in assessment included plain lateral films of the the spinal cord. Pathology was localised cervical spine and high definition computed primarily to the dorsal white matter and myelotomography with multiplanar refor- there was no evidence of vasculitis or matting.2' All operations were carried out by or ischaemic changes.
    [Show full text]
  • Theory on How Syrinxes Form
    Theories | 02.04 Key Points New Theory On How Syrinxes Form 1. Mathematical model, or Many theories on syrinx formation have come and gone over the years. While they vary in their details, most analysis, of the CSF system in modern theories focus on the dynamics of how CSF flows and under what conditions it would create a syrinx. Chiari and syringomyelia was Cerebrospinal fluid bathes the brain and spinal cord and acts as a protective cushion and shock absorber. In a created healthy person, CSF flows freely from the brain to the spinal region (around the cerebellar tonsils) and back again in concert with a person's heartbeat. When the cerebellar tonsils descend out of the skull and crowd the 2. It models the system as two, spinal cord, one of the main passages for this CSF can be blocked. For decades now, doctors and scientists co-axial tubes filled with fluid have been trying to understand how this blockage can lead to a syrinx forming in the spinal cord.. (CSF) Gardner kicked it all off with a theory that stated if a Chiari malformation blocks the natural flow of CSF out of the 3. New theory says that during a brain, it will be redirected and flow down the central canal of the spinal cord instead and create a syrinx. This cough or sneeze, a pressure theory may work for a subset of cases, but it has since been shown that in most adults, the central canal closes wave travels up the spine and off and would not allow this type of CSF flow.
    [Show full text]
  • MENINGES and CEREBROSPINAL FLUID' by LEWIS H
    MENINGES AND CEREBROSPINAL FLUID' By LEWIS H. WEED Department of Anatomy, John Hopkins University THE divorce of structure from function is particularly difficult in any ana- tomical study: it was only 85 years ago that the two subjects of morphology and physiology were considered to justify separate departments as academic disciplines. But with this cleavage which fortunately has not at any time been a rigid one, only certain investigations could go forward without loss of in- spiration and interpretation when studied apart from the sister science; other researches were enormously hampered and could be attacked only with due regard to structure and function. So it is without apologies that I begin the presentation of the problem of the coverings of the central nervous system -coverings which encompass a characteristic body fluid. Here then is a problem of membranes serving to contain a clear, limpid liquid as a sac might hold it. Immediately many questions of biological significance are at hand: how does it happen that these structures retain fluid; where does the fluid come from; where does it go; is the fluid constantly produced or is it an inert, non-circu- lating medium; is the fluid under pressure above that of the atmosphere; does it move about with changes in the animal body?-but the list of problems springing into one's mind grows too long. Knowledge regarding these many questions has progressed since the first accounts of hydrocephalus were given by writers in the Hippocratic corpus, since discovery of the normal ventricular fluid in Galen's time, since its meningeal existence was first uncovered by Valsalva (1911) and advanced by Cotugno (1779), since the first adequate description by Magendie (1825) 100 years ago.
    [Show full text]
  • Wnt/Β-Catenin Signaling Regulates Ependymal Cell Development and Adult Homeostasis
    Wnt/β-catenin signaling regulates ependymal cell development and adult homeostasis Liujing Xinga, Teni Anbarchiana, Jonathan M. Tsaia, Giles W. Plantb, and Roeland Nussea,c,1 aDepartment of Developmental Biology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305; bDepartment of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305; and cHoward Hughes Medical Institute, Stanford, CA 94305 Contributed by Roeland Nusse, May 22, 2018 (sent for review February 23, 2018; reviewed by Bin Chen and Samuel Pleasure) In the adult mouse spinal cord, the ependymal cell population that precursors and are present before the onset of neurogenesis. surrounds the central canal is thought to be a promising source of They give rise to radial glial cells, which then become the pre- quiescent stem cells to treat spinal cord injury. Relatively little is dominant progenitors during gliogenesis (19, 20). Eventually, known about the cellular origin of ependymal cells during spinal ependymal cells are formed as the ventricle and the ventricular cord development, or the molecular mechanisms that regulate zone retract through the process of obliteration. This process is ependymal cells during adult homeostasis. Using genetic lineage accompanied by terminal differentiation and exit of radial glial tracing based on the Wnt target gene Axin2, we have character- cells from the ventricular zone (18, 19, 21–24). ized Wnt-responsive cells during spinal cord development. Our Compared with our knowledge about ependymal cells in the results revealed that Wnt-responsive progenitor cells are restricted brain, little is known about the cellular origin of spinal cord to the dorsal midline throughout spinal cord development, which ependymal cells.
    [Show full text]
  • Forrest Hsu and Dr. Hurlbert FMC Nsx Halfday 07Jun07 Objectives
    Spinal Cord Cysts and Cavitations Forrest Hsu and Dr. Hurlbert FMC NSx Halfday 07Jun07 Objectives Definitions Pathophysiology/Classification Clinical Presentation Management “Syrinx” Greek mythological character Fluid filled cyst within spinal cord Syringohydromyelia: Syringomyelia: fluid collections outside of central canal Hydromyelia: fluid collections enlarging central canal, congenital, almost always benign. Usually lined by ependymal cells. Pathophysiology Rare, poorly understood natural history Associated w/: Trauma Chiari malformations Tumour Vascular malformations Arachnoiditis Occult Spinal Dysraphisms Traditional Classification Communicating Chiari Malformations Spinal Dysraphisms Non-Communicating Trauma Tumour Vascular Malformations Arachnoiditis Anatomical Classification Milhorat TH. Neurosurg Focus(2000):8(3) Communicating Syrinx’s caused by Obstruction below 4th Ventricle Communicating central canal dilatations are caused by obstructions of the CSF pathways distal to 4th Ventricle Etiology: Postmeningitic/Post hemorrhagic hydrocephalus Basilar/Medullary Archnoiditis Chiari II Malformations Encephalocele Dandy-Walker Cysts Natural Hx: Length defined by canal stenosis Congenital lesions may be contiguous (myelomenigocele) Rare to rupture/dissect paracentrally Most cases assymptomatic w/minor neuro findings Non-Communicating Syrinx’s caused by Obstruction @ Foramen Magnum Non-Communicating central canal dilatations are caused by obstructions of the CSF pathways at or below foramen magnum. Etiology: Chiari I malformations / Basilar
    [Show full text]