white matter

Examples of white matter in the following topics:

• Grey and White Matter

  • The basic pattern of the CNS is a central cavity surrounded by gray matter external to which is the white matter.
  • White matter only contains the myelinated axon tracts,  and not the cell bodies.  
  • Myelin also gives white matter its characteristic color.
  • This MRI highlights the location of white matter in the brain.
  • Distinguish between grey and white matter of the central nervous system

• Spinal Cord White Matter

  • The white matter of the spinal cord is composed of bundles of myelinated axons.
  • White matter is one of the two components of the central nervous system.
  • White matter in non-elderly adults is 1.7-3.6% blood.
  • The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons).
  • The spinal cord diagram showing location of the white matter surrounding grey matter.

• White Matter of the Cerebrum

  • White matter is composed of myelinated axons and glia and connects distinct areas of the cortex.
  • White matter is one of the two components of the central nervous system (CNS).
  • In a freshly cut brain, the tissue of white matter appears pinkish white to the naked eye because myelin is composed largely of lipid tissue containing capillaries.
  • White matter appears white in this dissected human brain, while gray matter appears darker.
  • White matter is composed largely of myelinated axons.

• Subdivisions of the Nervous System

  • The nervous system is often divided into components called gray matter and white matter.
  • Gray matter, which is gray in preserved tissue but pink or light brown in living tissue, contains a relatively high proportion of neuron cell bodies.
  • Conversely, white matter is composed mainly of axons and is named because of the color of the fatty insulation called myelin that coats many axons.
  • White matter includes all of the nerves of the PNS and much of the interior of the brain and spinal cord.
  • Gray matter is found in clusters of neurons in the brain and spinal cord and in cortical layers that line their surfaces.

• Carbon Monoxide Poisoning

  • Carbon monoxide is a product of incomplete combustion of organic matter due to insufficient oxygen supply to enable complete oxidation to carbon dioxide (CO2).
  • The result of these effects is lipid peroxidation, which causes delayed reversible demyelinization of white matter in the central nervous system known as Grinker myelinopathy, which can lead to edema and necrosis within the brain.
  • These disorders are typically related to damage to the cerebral white matter and basal ganglia.
  • Hallmark pathological changes following poisoning are bilateral necrosis of the white matter, globus pallidus, cerebellum, hippocampus, and the cerebral cortex.

• Clusters of Neuronal Cell Bodies

  • In anatomical sections, a nucleus shows up as a region of gray matter, often bordered by white matter.

• Motor Areas

  • Buried deep in the white matter of the cerebral cortex are interconnected subcortical masses of cerebral gray matter called basal nuclei (or basal ganglia) that are involved in motor control.

• Premature Infants

  • Children born preterm are more likely to have white matter brain abnormalities, causing higher risks of cognitive dysfunction.
  • White matter connectivity between the frontal and posterior brain regions is critical in learning to identify patterns in language.

• Somatic Sensory Pathways to the Cerebellum

  • The axon runs via the fila radicularia (nerve rootlets) to the dorsal horn of the gray matter.
  • Once in the deep, white matter of the cerebellum, the axons recross the midline, give off collaterals to the globose and emboliform nuclei (deep cerebellar nuclei), and terminate in the cortex of the anterior lobe and vermis of the posterior lobe.

• Types of WBCs

  • The different types of white blood cells (leukocytes) include neutrophils, basophils, eosinophils, lymphocytes, monocytes, and macrophages.
  • White blood cells (WBCs), or leukocytes, are immune system cells that defend the body against infectious disease and foreign materials.
  • A major distinguishing feature is the presence of granules; white blood cells are often characterized as granulocytes or agranulocytes.
  • MN leukocytes contain lysosomes, small vesicles containing digestive enzymes that break down foreign matter that is endocytosed by the cell during phagocytosis.
  • Distinguish between the two major types of leukocytes (white blood cells): granulocytes and agranulocytes