Histo Lec 18

• nervous system


  - complex grouping of organs

  - composed of nervous tissues
• cns

  pns


  2 major subdivisions of nervous systems
• brain, spinal cord


  CNS is composed of
• a. Ganglia

  b. Nerve trunks

  c. Nerve endings


  pns is composed of
• somatic

  autonomic


  Anatomic subdivision of PNS
• 1. Meninges

  a. Dura mater

  b. Arachnoidea

  c. Pia mater

  2. Choroid plexus

  3. CSF

  4. Spinal cord

  5. Cerebellum

  6. Cerebrum


  Components of the Central Nervous System
• meninges


  are the fibrous membrane enclosing the CNS
• dura mater

  arachnoid

  pia mater


  3 layers of meninges
• outer layer

  inner layer


  two layers of meninges in the brain
• outer layer of meninges in brain


  is the fibrous periosteum of the inner surface of the cranial bones
• inner layer of meninges in brain


  poorly vascularized layer which blends with the outer layer
• responsible for collection of cerebrospinal fluid and its return to the vascular system


  function of dural sinuses
• subdural space.


  The dura is separated from the arachnoid by a
• inner layer of the cranial dura


  one layer of dura of the spinal cord is called?
• epidural space


  dura of the spinal cord has only one layer (inner layer of the cranial dura) and is separated from the periosteum of the vertebrae by the
• used for administration of epidural anesthesia


  epidural space function
• arachnoid


  Membrane w/ numerous fibrous trabeculae on its inner surface
• pia mater


  most intimate protective membrane of brain and spinal cord
• - very fine collagenous and elastic fibers

  - as well as small vessels.


  pia mater is composed of?
• covered by mesothelial-like epithelium

  pia mater
• Choroid Plexus


  vascular network of the pia mater
• choroid plexus


  Folds of pia mater containing capillaries covered w/ thin cuboidal epi
• produces csf


  function of choroid plexus
• cerebrospinal fluid


  clear, colorless fluid
• Cerebrospinal fluid

  - fills ventricular system and central canal of the spinal cord

  - occupies the subarachnoid space
• choroid plexuses of the lateral, third and fourth ventricles of the brain


  csf is produced by?
• cushion cns

  acts as lymphatic channel


  function of cerebrospinal fluid
• Spinal Cord


  slender portion of the neural tube

  round to oval form in a cross-section
• gray matter

  white matter


  2 division of spinal cord
• gray matter


  H or butterfly pattern.
• gray matter


  located in the middle of spinal cord surrounded matter
• - nerve cell bodies

  - unmyelinated nerve fibers

  - some myelinated nerve fibers

  - protoplasmic astrocytes

  - oligodendrocytes

  - microgliocytes

  - some blood vessels and

  - fine connective tissue fibers.


  gray matter consists of the
• Large multipolar motor neurons

  ventral gray columns
• Medium-sized neurons


  lateral gray columns of the thoraco-lumbar segments
• small neurons


  - dorsal gray columns

  - have axons
• spinal canal


  Found in gray commissure and lined by ependymal cells
• white matter


  composed of myelinated nerve fibers and some unmyelinated nerve fibers, neuroglial cells and blood vessels
• - dorsal funiculus

  - lateral funiculus

  - ventral funiculus


  white matter division (3)
• Dorsal Funiculus


  region between the dorsal gray columns (white matter)
• Lateral Funiculus


  portion between two adjacent dorsal and ventral columns (white matter)