gray matter

(noun)

A major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astroglia and oligodendrocytes), and capillaries.

Related Terms

  • central nervous system
  • peripheral nervous system
  • white matter

Examples of gray matter in the following topics:

  • Grey and White Matter

    • The basic pattern of the CNS is a central cavity surrounded by gray matter made up of neuronal cell bodies external to which is the white matter which is made up of myelinated axons.
    • The basic pattern of the CNS is a central cavity surrounded by gray matter external to which is the white matter.
    • The spinal cord exhibits this basic pattern, but the brain has additional regions of gray matter not present in the spinal cord.
    • Both the cerebrum and cerebellum have an outer additional layer of gray matter.
    • Gray matter is a major component of the central nervous system, consisting of neuronal cell bodies.  
  • Spinal Cord White Matter

    • White matter is the tissue through which messages pass between different areas of gray matter within the nervous system.
    • Using a computer network as an analogy, the gray matter can be thought of as the actual computers themselves, whereas the white matter represents the network cables connecting the computers together.
    • The brain in general (and especially a child's brain) can adapt to white-matter damage by finding alternative routes that bypass the damaged white-matter areas, and can therefore maintain good connections between the various areas of gray matter.
    • Aggregates of gray matter such as the basal ganglia and brain stem nuclei are spread within the cerebral white matter.
    • "Type 1 astrocytes" had a fibroblasts appearance and resided in both gray matter and white matter.
  • 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.
    • 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.
    • By convention, a cluster of neuron cell bodies in the gray matter of the brain or spinal cord is called a nucleus, whereas a cluster of neuron cell bodies in the periphery is called a ganglion.
  • Cerebral Cortex

    • The cerebral cortex, the largest part of the mammalian brain, is the wrinkly gray outer covering of the cerebrum.
    • The cerebrum is composed of gray and white matter.
    • Gray matter is the mass of all the cell bodies, dendrites, and synapses of neurons interlaced with one another, while white matter consists of the long, myelin-coated axons of those neurons connecting masses of gray matter to each other.
    • A sagittal cross-section of a human brain showing the distinct layers of grey matter (the darker outer layer) and white matter (the lighter inner layer) in the cerebrum.
  • Medulla Oblongata

    • It is caused by a large mass of gray matter known as the inferior olivary nucleus.
    • They are caused by masses of gray matter known as the nucleus gracilis and the nucleus cuneatus.
    • It is caused by an underlying collection of gray matter known as the spinal nucleus of the trigeminal nerve.
    • The gray matter of this nucleus is covered by a layer of nerve fibers that form the spinal tract of the trigeminal nerve.
  • Sensory-Somatic Nervous System

    • Motor neurons have cell bodies in the ventral gray matter of the spinal cord that project to muscle through the ventral root.
    • The cell bodies of motor neurons are found in the ventral portion of the gray matter of the spinal cord.
  • 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.
    • The axons of white matter transmit signals from various grey matter areas (the locations of nerve cell bodies) of the cerebrum to each other and carry nerve impulses between neurons.
    • White matter appears white in this dissected human brain, while gray matter appears darker.
    • White matter is composed largely of myelinated axons.
  • Measuring Radiation Exposure

    • Radiation dosimetry is the measurement and calculation of the absorbed dose in matter and tissue resulting from exposure to indirect and direct ionizing radiation.
    • Dose is reported in gray (Gy) for matter or sieverts (Sv) for biological tissue, where 1 Gy or 1 Sv is equal to 1 joule per kilogram.
    • Radiation dose refers to the amount of energy deposited in matter and/or biological effects of radiation.
    • Define the terms used to define radiation exposure, the gray (Gy) and sievert (Sv)
  • Radiation

    • Similarly, black asphalt in a parking lot will be hotter than the adjacent gray sidewalk on a summer day, because black absorbs better than gray.
    • The reverse is also true—black radiates better than gray.
    • Thus, on a clear summer night the asphalt will be colder than the gray sidewalk because black radiates energy more rapidly than gray.
    • Gray objects have a uniform ability to absorb all parts of the electromagnetic spectrum.
    • In other words, it does not matter whether the surroundings are white, gray, or black; the balance of radiation into and out of the object depends on how well it emits and absorbs radiation.
  • Racial Tensions and Black Lives Matter

    • On April 12, 2015, Baltimore Police Department officers arrested Freddie Gray, a 25-year-old African American resident of Baltimore, Maryland, for possessing what the police alleged was an illegal switchblade.
    • Gray sustained heavy injuries to his neck and spine while in transport in a police vehicle and fell into a coma.
    • Gray died the following day, April 19, 2015, a week after the arrest.
    • Garza wrote a Facebook post titled "A Love Note to Black People" in which she wrote: "Our Lives Matter, Black Lives Matter."
    • Tometi then added her support, and Black Lives Matter was born as an online campaign.
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