Top Banner

of 20

5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

Apr 05, 2018

Download

Documents

Mudassar Roomi
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    1/20

    HISTOLOGY OF NERVOUS TISSUE

    BY

    DR. MUDASSAR ALI ROOMI (MBBS, M. PHIL)

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    2/20

    Cerebrum is the

    largest part of brain.

    Histolgically, Cerebral

    cortex varies in

    different parts of the

    cerebrum

    Allocortex: simplestcortex. it has got only

    two layers e.g. the

    olfactory cortex.

    Neocortex: consists ofsix superimposed

    layers. Most of the

    cortex is of this type.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    3/20

    Like cerebellum, the cerebrum also has a cortex

    of grey matter on the surface and inner whitematter.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    4/20

    Cells of the cerebral cortex

    Pyramidal cells

    Non-pyramidal cells:

    1. Stellate cells (granule cells)2. Horizontal cells

    3. Martinotti cells

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    5/20

    Pyramidal cells

    Multipolar neurons

    Pyramid shaped cell bodies

    Large vesicular nucleus

    Abundant Nissl granules in thecytoplasm

    Dendrites: one main apicaldendrite and run towards themost superficial layer ofcortex. Some other smalldendrites are also present.

    Axon: arises from the centreof base and runs in the whitematter.

    Small, medium and large-sizedpyramidal cells.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    6/20

    Pyramidal cells

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    7/20

    Non-pyramidal cells

    1. Stellate cells (also called as granule

    cells because of their small size)2. Horizontal cells: found in the most

    superficial layer

    3. Martinotti cells: found in the

    deeper layers.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    8/20

    Layers of cerebral cortex

    1. Molecular or plexiform layer: chiefly

    composed of cell processes. Some

    horizontal cells are also present.

    2. External granular layer: contains small

    pyramidal cells and numerous closely

    packed stellate cells.

    3. External pyramidal layer: composed

    mainly of large pyramidal cells and some

    granule cells

    4. Internal granular layer: consists of closely

    packed stellate cells. Nerve fibers makeouter Band of Baillarger.

    5. Internal pyramidal layer or ganglionic

    layer (Betz cells): contains large pyramidal

    cells., stellate cells and Martinotti cells.

    Nerve fibers make inner Band of Baillarger.

    6. Multiform layer: it contains neurons of

    many shapes. Pyramidal cells, stellate cellsand Martinotti cells

    HORIZONTAL

    CELLS

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    9/20

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    10/20

    How to draw it!

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    11/20

    Cerebrum- identification points

    Outer grey matter

    having six layers

    Pyramidal cells

    Inner white matter

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    12/20

    MENINGES

    The brain and spinal cordis invested by three C.T.coverings called as

    meninges. Mater= mother

    1. Pia mater, which is theinnermost.

    2. Arachnoid mater, whichis external to pia mater.

    3. Dura mater, which is theoutermost.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    13/20

    MENINGES

    AROUND BRAIN

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    14/20

    MENINGES

    AROUNDSPINAL CORD

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    15/20

    DURA MATER

    Dura= hard (latin word).

    Is has got tough consistency

    Composed of denseconnective tissue

    The dura mater is alwaysseparated from thearachnoid by the thin

    subdural space.

    Inner surface of dura materis covered by lining of flatcells of mesenchymal origin.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    16/20

    ARACHNOID MATER

    arachnoeides= spiderweblike (Greek

    word)

    It Consists of thin layer of connective

    tissue

    It has two components: (1) a sheet of

    connective tissue in contact with the dura

    mater and (2) a system of loosely

    arranged trabeculae containing fibroblasts

    and collagen.

    This trabecular system is continuous with

    the deeper pia mater.

    Surrounding the trabeculae is a large,

    sponge-like cavity, the subarachnoidspace, filled with CSF.

    This space forms a hydraulic cushion that

    protects the CNS from trauma.

    Both the surfaces of the arachnoid mater

    are covered by continuous layer of flat

    cells.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    17/20

    ARACHNOID MATER (cont.)

    The connective tissue of thearachnoid is said to beavascular because it lacksnutritive capillaries, but largerblood vessels run through it.

    The arachnoid and the piamater are intimatelyassociated and are oftenconsidered a single membranecalled the pia-arachnoid(leptomeninges).

    Infection of leptomemninges iscalled as meningitis

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    18/20

    ARACHNOID MATER (cont.)

    In some areas, thearachnoid perforates thedura mater and protrudesinto blood-filled venoussinuses within the dura

    mater. These CSF-filledprotrusions, which arecovered by vascularendothelial cells, are calledarachnoid villi.

    Their function is totransport CSF from thesubarachnoid space intovenous sinuses.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    19/20

    PIA MATER

    Pia= delicate

    It is a thin layer ofconnective tissue

    adherent to the surface of

    nervous tissue Towards the

    subarachnoid space, thepia mater is lined by acontinuous layer of flat

    cells that resembles themesothelial lining of thebody cavities.

  • 7/31/2019 5. Lecture on the Histology of Cerebrum and Meninges by Dr. Roomi

    20/20

    Slide show meninges