Just medial (to the right) of the tail of the caudate, note the choroid plexus slide NP004N View Image, which consists of highly convoluted and vascularized villi covered by ependymal cells which are specialized for the production of cerebrospinal fluid, or CSF. But most everything else cannot, including white blood cells, which are one of the bodys main lines of defense. Nails are plates of proliferating keratinized cells that, similar to hair, contain hard keratin. Based on morphology, epithelial cells can be either squamous (flat), cuboid (cube) or columnar (rectangular). within limits that maintain life. Ross, H. M, Pawlina, W. (2011). Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster. The tools for studying histology are becoming more diverse everyday. The digestive system consists of the alimentary canal and its associated organs (tongue, teeth, salivary glands, pancreas, liver and gallbladder). Many axons are wrapped by an insulating substance called myelin, which is actually made from glial cells. Ependymal cells line each ventricle, one of four central cavities that are remnants of the hollow center of the neural tube formed during the embryonic development of the brain, as well as the central canal of the spinal cord. It consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus. Depending on the number of layers, epithelial tissue is classified into simple (single layered) or stratified (multi-layered). The dendritic tree and axon of each Purkinje cell can only be seen in thicker sections stained with special silver stains. Microglia are, as the name implies, smaller than most of the other glial cells. It contains connective tissue, mostly composed of adipocytes. An important part of the function of neurons is in their structure or shape. The three-dimensional shape of these cells makes the immense numbers of connections within the nervous system possible. It consists of neurons and supporting cells called neuroglia. The nervous system is responsible for all our. Sensory reception is a peripheral function (those dendrites are in the periphery, perhaps in the skin) so the cell body is in the periphery, though closer to the CNS in a ganglion. In a transverse section of a nerve (Figure 10), single myelinated axons look like little circles organized in bundles called fascicles. This is a tapering of the cell body toward the axon fiber. Muscle tissue maintains synthesizing and contractile functions. They are electrically active and release chemical signals to target cells. The cerebellum is the part of the brain responsible for integrating input from the sensory organs to coordinate the precise, voluntary movements originally initiated in the cerebral cortex. Human unipolar cells have an axon that emerges from the cell body, but it splits so that the axon can extend along a very long distance. Be able to identify tissues in the nervous system (nerves, cell bodies and ganglia, and white vs. gray matter in the spinal cord, cerebellum, and cerebrum). But what makes neurons special is that they have many extensions of their cell membranes, which are generally referred to as processes. Confusingly, structures within white and grey matter are referred to by different terms, depending on whether they are located in the CNS or the PNS. The dorsal nucleus of Clarke slide 066a View Image is in the dorsal horn and contains relatively large, multipolar neurons that receive proprioceptive information from dorsal root ganglion cells that are innervated by muscle spindles in the trunk and lower limb. In the PNS, myelin is produced by Schwann cells, which wrap around the axon. However, the endothelial cells maintain these junctions in response to signals (via foot processes) from ASTROCYTES. They provide support, performing similar functions in the periphery as astrocytes do in the CNSexcept, of course, for establishing the BBB.The second type of glial cell is the Schwann cell, which insulate axons with myelin in the periphery. Histology (Tissues). Recall thatSchwann cells are the glial cells responsible for myelination in the peripheral nervous system. The layers of the blood-air barrier comprise of type I pneumocytes, basement membrane and endothelial cells of the capillaries. Pulmonary capillaries come into close contact with the alveoli, forming the blood-air barrier. It relays sensory input to cerebral cortex. How about the fact that some cardiomyocytes have the ability to secrete hormones that regulate blood pressure? 1. You may be able to see subtle differences in the distribution of cell types in rather loosely demarcated layers. The ventral spinal cord. This actually causes problems with drug delivery to the CNS. Neurons are the cells considered to be the basis of nervous tissue. Nervous tissue contains two categories of cellsneurons and neuroglia. Aside from finding efficacious substances, the means of delivery is also crucial. ("6" in the orientation figure) a molecular layer containing dendrites of the granule cells. between a tract and a nerve? Ppt #2. Mesenchyme gives rise to all types of connective tissue. The branch of medical science that deals with the. Review the organization of gray and white matter in cerebral cortex vs. spinal cord. The ECM contains different protein fibers (collagen, reticular, elastic) embedded in ground substance. It is permeable to oxygen, carbon dioxide and other gases, allowing for the occurrence of gas exchange. Neurons are characterized by a large cell body or perikaryon containing a large, pale (active, euchromatic) nucleus with a prominentnucleolus. The tissues of the nervous system can also be divided into grey matter and white matter. Read more. The dermis is a layer of connective tissue that contains collagen fibers, blood vessels, lymphatics and nerve endings. It monitors and regulates the functions of the body. If you are a University of Michigan student enrolled in a histology course at the University of Michigan, please click on the following link and use your Kerberos-password for access to download lecture handouts and the other resources. Thus, in the 'white matter' of the brain and spinal cord, myelinated axons are the predominant neuronal cell component and most of the the nuclei that you see in white matter are primarily of glial cells. 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" whereas the "newer" six-layered cerebral cortex is "neocortex"). One cell providing support to neurons of the CNS is the astrocyte, so named because it appears to be star-shaped under the microscope (astro- = star). Nerve tissue consists of 2 principal types of cells: neurons and supporting cells. Nervous tissue. It is made up of gray matter and white matter. While their origin is not conclusively determined, their function is related to what macrophages do in the rest of the body. They are responsible for the computation and communication that the nervous system provides. That single axon can branch repeatedly to communicate with many target cells. Then, get ready to test your knowledge! Examine the cross section of the lumbar spinal cord in slide 065-2. Note that sacral levels of the cord (levels S2-4) also contain visceral motor neurons in the lateral horn, but these are parasympathetic. They are responsible for the electrical signals that communicate information about sensations, and that produce movements in response to those stimuli, along with inducing thought processes within the brain. The spleen on the other hand, filters blood. Both respond immunologically to foreign material in the fluid passing through. Movement on one side of the body is often controlled by nerve impulses originating on the opposite side of the brain. Junquieras Basic Histology (13th ed.). Type II pneumocytes are also important because they secrete surfactant which prevents the lungs from collapsing. It is the axon that propagates the nerve impulse, which is communicated to one or more cells. Nervous Tissue DR. DEVI 1 16-4-19 2. Pharmaceutical companies are challenged to design drugs that can cross the BBB as well as have an effect on the nervous system. In this article, we will introduce you to the microscopic world of histology. Vocal cords are housed in the larynx, formed by two folds of mucosa, each containing a supporting ligament (vocalis ligament) and a skeletal muscle (vocalis muscle). Primary lymphoid organs (bone marrow and thymus) produce lymphocytes (B and T cells) while secondary lymphoid organs (diffuse lymphoid tissues, lymphatic nodules, lymph nodes and spleen) help to rid the body of toxins, waste and other unwanted material. The name suggests that it has no axon (an- = without), but this is not accurate. Above the temporal (ventral or inferior) horn of the lateral ventricle the lateral geniculate nucleus is present. They are responsible for the computation and . 1:00 - 2:55 Cartilage and Bone ppt | pdf | lecture recording. The lighter-colored layers on both sides of the axon are myelin. Figure 1 shows the relationship of these parts to one another. EM works by emitting parallel beams of electrons onto the tissue sample. Pyramidal cells in the cerebral cortex act as upper motor neurons, which then synapse with the lower motor neurons that are in direct contact with muscles to initiate contraction. True unipolar cells are only found in invertebrate animals, so the unipolar cells in humans are more appropriately called pseudo-unipolar cells. Be sure you identify the white matter in bothluxol blue-stainedslide 076View ImageandTB&E-stained#076bView Imagesections, as it will appear differently in these two stains. DiFiores atlas of histology with functional correlations. Anaxonic neurons are very small, and if you look through a microscope at the standard resolution used in histology (approximately 400X to 1000X total magnification), you will not be able to distinguish any process specifically as an axon or a dendrite. Glial cells, or neuroglia or simply glia, are the other type of cell found in nervous tissue. The nervous system can be organized in several different ways. The axons of pyramidal cells will descend through the interior white matter of the cerebrum into the three parts of the brainstem: the midbrain, the pons, and the medulla. as white matter? They are considered part of the mononuclear phagocytic system and will proliferate and become actively phagocytic in regions of injury and/or inflammation. They are separated into four categories: muscular, nervous, epithelial and connective. Click on the tissue and observe. Scattered in the cytoplasm are the characteristic clusters of ribosomes and rough ER termed Nissl bodies or Nissl substanceslide 066aView Image. The latter constitutes the diffuse neuroendocrine system (DNES). Many types of glial cells require special histological stains and cant be unambiguously identified in regular H&E-stained histological slides. Four of them are found in the CNS and two are found in the PNS. Glial cells, or glia, are known to play a supporting role for nervous tissue. Nonetheless, it is loosely stratified into layers containing scattered nuclei of both neurons and glial cells. Slides include types of epithelial, connective, nervous, and muscle tissue and is ideal for an anatomy and physiology course. The lipids are essentially the phospholipids of the glial cell membrane. Calcific bodies are present in the choroid plexus, another common site of accumulation as the years pass. It relays sensory input to cerebellar cortex. Learn more about the histology of the upper and lower digestive tract. Name the part of the central nervous system that isdisplayed in this tissue section. For Schwann cells, the outermost layer of the cell membrane contains cytoplasm and the nucleus of the cell as a bulge on one side of the myelin sheath. Study with Quizlet and memorize flashcards containing terms like Afferent, efferent, visceral and more. Body tissues are collections of cells, grouped in the body according to structure and function. Tissues join together in different arrangements to form our body organs. All rights reserved. Electron microscopy (EM) is a more modern form of microscopy that provides a much higher magnification and high resolution images. The cardiovascular system consists of the heart and blood vessels (arteries, arterioles, capillaries, venules, veins). Astrocytes have many processes extending from their main cell body (not axons or dendrites like neurons, just cell extensions). T and B lymphocytes are born and raised in the thymus and bone marrow, respectively. The musculoskeletal system consists of hard tissues (bones, joints, cartilage) and soft tissues (muscles, tendons, ligaments). Astrocytes - Technically, the junctions between endothelial cells constitute the actual "barrier." At a microscopic level, a nephron consists of a renal corpuscle and a series of tubules. This Power point presentation will allow students to practice the skill of identifying tissue types from 25 histology slides. Myelin is lipid-rich, and on gross inspection appears white. With one exception, neurons such as this (though not necessarily this large) are found in ALL areas of the nervous system. This is why doctors must take extra caution when prescribing medication to these people. Axon diameters can be as small as 1 to 20 micrometers. These hormones regulate a variety of processes, such as metabolism, growth and blood pressure. They are organized into lobules, with each lobule containing a parenchyma of seminiferous tubules and a connective tissue stroma. It consists of widely separated mesenchymal cells and ground substance with an abundance of hyaluronic acid. 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. A few other processes provide the same insulation for other axon segments in the area. The name glia comes from the Greek word that means glue, and was coined by the German pathologist Rudolph Virchow, who wrote in 1856: This connective substance, which is in the brain, the spinal cord, and the special sense nerves, is a kind of glue (neuroglia) in which the nervous elements are planted. Today, research into nervous tissue has shown that there are many deeper roles that these cells play. Pia mater 2. Neurons are usually described as having one, and only one, axona fiber that appears as a long cord emerging from the cell body and projects to target cells. ("4" in the orientation figure) a polymorphic layer containing nerve fibers (known as "mossy fibers") and cell bodies of interneurons, ("5" in the orientation figure) a middle granule cell layer containing the round, neuronal cell bodies of dentate granule cells.