The area labeled dr is a part of the dorsal root that runs from this ganglion to the spinal cord. The hippocampus and dentate gyrus function in what is known as the "limbic system" to integrate inputs from many parts of the nervous system into complicated behaviors such as learning, memory, and social interaction beyond the scope of what can be described here. This preparation of neural tissue from spinal cord shows large neurons which are probably somatic motor neurons. Furthermore, across this boundary the mapping of visual space actually reverses (more on “visuotopy” in January when we study central visual processing). (See below.) The axon may be identifiable by the notable ABSENCE of Nissl substance at the axon hillock; however, this is not always so easy to see by light microscopy. Scattered in the cytoplasm are the characteristic clusters of ribosomes and rough ER termed Nissl bodies  or Nissl substance. Most of the nuclei seen within the white matter tracts most likely belong to oligodendrocytes [example], although there are certainly quite a few astrocytes mixed in as well, so the only way to really know for sure is with immunostaining with antibodies specific to oligodendrocytes. Electronic address: adalberto.merighi@unito.it. I. Spinal Cord a. Recall during development, newly formed neurons proliferate adjacent to the canal to form a mantle layer, which becomes the gray matter in the central region of the mature spinal cord. The information can be in the form of hand-written or printed text or symbols and gives details about manufacturer’s name, source of product, shelf-life, uses and the manner of disposal. Axons can be very long - around 1 metre, and vary in diameter from 0.2 to 20 µm Lateral to this structure is the tail of the caudate. The converse is true: just about anything deemed by biomedical or social science to be unhealthy or maladaptive seems to promote destructive plasticity and reduction in hippocampal volume. The white matter is composed of nerve fibers carrying ascending and descending information and makes up the outer regions of the cord. ("1" in the orientation figure) a polymorphic layer containing many nerve fibers and small cell bodies of interneurons. C. Astrocytes Many types of glial cells require special histological stains and can’t be unambiguously identified in regular histological slides. Duke University | Duke Medicine | School of Medicine | School of Nursing | Doctor of Physical Therapy Learn vocabulary, terms, and more with flashcards, games, and other study tools. b. Slide 76b (cerebrum, toluidine blue & eosin) [DigitalScope] This section is stained with thionine, which highlights the presence of Nissl substance. Lab 4 - External and Internal Anatomy of the Spinal Cord Purpose: The spinal cord constitutes a vital link between the brain and most of the body. This feature of BA 17 is easy to recognize in slide 305. Click here to submit questions or comments about this site. Labels are a means of identifying a product or container through a piece of fabric, paper, metal or plastic film onto which information about them is printed. They are considered part of the mononuclear phagocytic system and will prolifereate and become actively phagocytic in regions of injury and/or inflammation. This gray matter occupies a butterfly-shaped cross-section in this mature spinal cord. Review the organization of the spinal cord using an anatomy atlas, then examine the cross section of the lumbar spinal cord in slide #65-2. Besides identification which is a major purpose of labels they can also be used for furnishing usage instructions, promotional purposes, environmental adviceor warning notification. To orient you to this section, dorsal is toward the top of the image and anterior is toward the left. Product labels in the food and beverage industry and automobiles are required to remain on a permanent basis. Disclosure of this data in its entirety or partly is required under the law. The white matter fills most of this cross-section external to the central butterfly-shaped region of gray matter. In this article, we shall examine the macroscopic anatomy of the spinal cord – its structure, membranous coverings and blood supply. Like the vertebral column, the spinal cord is divided into segments: cervical, thoracic, lumbar, sacral, and coccygeal. Now that you are oriented to the general presentation of “neocortex” (i.e., newer in evolutionary terms and typically six-layered), inspect slide 303, which was obtained from the paracentral lobule in a parasagittal plane of section. Deep to the gray matter of the cerebral cortex is the white matter that conveys myelinated fibers between different parts of the cortex and other regions of the CNS. Slide 304 is a thionine stain, which highlights the presence of Nissl substance, and slide 305 is a Gallyas silver stain, which produces a medium brown stain in myelin. Lab 1: Cells and Organelles WSU_1_056: Spinal Cord In this section, lining ependymal cells can be seen all along the interface of the gray matter and the ventricles [example]. What might be the functional significance of so many sublaminae in cortical layer IV within BA17? As you browse through the cerebral cortex in slide 76 and 76b, especially at high magnification, keep in mind that roughly half of the cells that you see are neurons and the other half are glia (and vascular endothelial) cells. The tiny central canal recalls the origin of the nervous system as an infolding which closes off to form the neural tube. ), Ch 16, Nervous System, determine the dorsal and ventral aspects of the cord, differentiate gray matter from white matter, note the central canal lined by ependymal cells, Outer plexiform (molecular) layer: sparse neurons and glia, Outer granular layer: small pyramidal and stellate neurons, Inner granular layer: densely packed stellate neurons (usually the numerous processes aren’t visible, but there are lots of nuclei reflecting the cell density), Multiform cell layer: mixture of small pyramidal and stellate neurons, the cortex of the precentral (motor) gyrus is about 50% thicker than the cortex of the postcentral (sensory) gyrus, the postcentral gyrus appears much more typical, in terms of six recognizable neocortical layers, compared to the precentral gyrus in which the layers are much more difficult to recognize, the density of cells (neurons and glia) is much greater in the postcentral gyrus compared to the precentral gyrus, there is more neuropil (unstained space between cell bodies in a Nissl stain) in the precentral gyrus compared to the postcentral gyrus. Look careful at these two cortical gyri and notice their differences. Most of the nuclei visible in the granular layer belong to very small neurons called granule cells, which participate in the extensive intercommunication involved in the cerebellum’s role in balance and coordination. The neurons of the mantle layer produce processes that grow outward to form the fiber tracts of white matter, which carry parallel myelinated axons for long-range interneuronal contacts in CNS. A. Ependymal cells / Choroid Plexus / Oligodendrocytes The spinal cord, roots, and distalmost cauda equina and filum terminale (Figure 1.2) are often considered separately, especially in view of the paraspinal soft tissue pathology, which can affect the integrity of the spinal cord. Spinal Cord Histology Labeled. Spinal Cord 400X The largest cells in the spinal cord are motor neurons (mn). There are 8 pairs of cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal pair of spinal nerves (a total of 31 pairs). The gray matter contains the nerve cell bodies, and the white matter is composed of axon tracts.In the spinal cord, the gray matter is on the inside, unlike the brain where it is in the outer portion (cortex), and it has a butterfly configuration. You may see small calcific bodies in part of the hippocampus, which occur as a normal part of the aging process. Be sure you identify the white matter in both luxol blue and TB&E-stained sections, as it will appear differently in these two stains. One or more cell processes may also be seen emerging from the neuronal perikaryon. dendritic) processes. The spinal cord is a tubular bundle of nervous tissue and supporting cells that extends from the brainstem to the lumbar vertebrae.Together, the spinal cord and the brain form the central nervous system. ; The spinal cord is composed of neurons that send and receive signals along tracts towards and away from the brain. Many of these astrocytes send out processes that contact and wrap around nearby capillaries, which are also clearly recognizable as tube-shaped segments. Finally, do the same for the posterior border of BA 3 where it transitions to BA 1 (yet another division of the primary somatic sensory cortex) in the crown of the postcentral gyrus. Slide NP004N has been stained with luxol blue, which preferentially stains white matter and can be seen as the dark purple areas beneath the cortex. In addition to the dorsal and ventral horns, two structures especially obvious in the thoracic cord are the dorsal nucleus of Clarke and the lateral horn. General organization. Start studying A+P Lab- Nervous system Histology; Anatomy of Brain and Cranial Nerves; Spinal Cord and Spinal Nerves. Because this is a section, and not a smear, you cannot see the processes. The cells here are preganglionic sympathetic motor neurons whose axons terminate in either sympathetic chain ganglia or the "visceral" (or "pre-aortic") ganglia associated with the major branches of the abdominal aorta (e.g. The small dark spot inside the cell is its nucleus. As we will discuss in Units 10&11, the central nervous system consists of white and gray matter. II. This study examined the spinal cord distribution of the endogenous opioid peptide leucine-enkephalin in the cat using immunohistochemical techniques. Certain reflexes are controlled by mechanisms within the spinal cord. 3 SPECIAL HISTOLOGY Part 1 LESSON 26 Spinal ganglion.Nerve. Neurons of the cerebral cortex are of varying shapes and sizes, but the most obvious are pyramidal cells. Many neurons in the spinal cord may appear shrunken and surrounded by an empty space due to poor fixation. Indeed, you may find it challenging to recognize the six conventional layers of the neocortex, as described above. In this particular stain (H&E) the grey matter can be seen in a slightly darker shade than the white matter. The small dark spots are the nuclei of supporting cells (sc). Now, compare slides 304 and 305 and see if you can determine how the stria of Gennari fits into cortical layer IV in the Nissl stain. celiac, aorticorenal, and superior/inferior mesenteric ganglia). Each somatic motor neuron has an axon which extends out of the spinal cord in a nerve and branches to contact a number of skeletal muscle cells. Immunohistochemical localization of leucine-enkephalin in the spinal cord of the cat: enkephalin-containing marginal neurons and pain modulation. c. Slide 303 (human paracentral lobule, thionine stain for Nissl substance) [DigitalScope]. Myelin is lipid-rich, and on gross inspection appears white. In the hippocampus [ORIENTATION], observe: In the dentate gyrus [ORIENTATION], observe: The "hilus" is the region where the head of hippocampus abuts the dentate gyrus. The white matter contains nerve fibers (axons) entering and exiting the gray matter, and traveling up and down the spinal cord, linking it to the brain. Search for: Navigation . a. Look at the section with the lowest magnification and identify the gray matter (contains large neuronal cell … Slide 76 (cerebrum, luxol blue/cresyl violet) [DigitalScope] The spinal cord is bilaterally symmetrical. In cross-section, the spinal cord is divided into the butterfly-shaped grey matter and surrounding white matter.    Be sure you identify the white matter in both luxol blue [example] and TB&E-stained [example] sections, as it will appear differently in these two stains. Histological inspection reveals that each nerve fibre is actually composed of a large number of axons whose cell bodies reside in central or peripheral ganglia, the spinal cord or the brain. a. Thus, in the 'white matter' of the brain and spinal cord, myelinated axons are the predominant neuronal component whereas most of the the nuclei that you see in white matter are primarily of glial cells. Animals move over a range of speeds by using rhythmic networks of neurons located in the spinal cord. For now, focus just on the morphology of these regions and observe the presence of three distinct layers rather than the six layers found in the cerebral cortex (evolutionarily speaking, the three-layered organization is considered to be "older," so this type of cortex is also known as "archicortex"). Each segment of the spinal cord provides several pairs of spinal nerves, which exit from vertebral canal through the intervertebral foramina.