The delicate meshwork of dendritic processes and nerve fibers (axons) lying between cells in the gray matter is called the neuropil. Ependymal cells, which are uniquely located lining the ventricles of the brain the central canal of the spinal cord, are one notable exception. The name suggests that it has no axon (an- = without), but this is not accurate. Junquieras Basic Histology (13th ed.). Movement on one side of the body is often controlled by nerve impulses originating on the opposite side of the brain. Histology of nervous tissue1 Kifayat Khan 855 views 26 slides Nervous tissue2k1 Hatesh Mahtani 4.8k views 109 slides General histology || Nervous tissue Ali Nasser 457 views 8 slides Nervous tissue i kohlschuetter 3.3k views 25 slides Nervous tissue 1 aiyub medicine 4.3k views 90 slides Introduction to Neuropathology Cassie Porebski 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. The glomerulus contains some interesting cells, such as mesangial cells which have supportive and phagocytic properties; juxtaglomerular cells that secrete renin which acts, in a broad sense, to help regulate our blood pressure; podocytes that control the permeability of the filtration membrane; and many more. Friday, August 26 The CNS consists of nervous tissue that is protected within bony structures the brain within the cranium and the spinal cord within the vertebral column. It consists of internal genitalia (vagina, uterus, uterine tubes, ovaries) and external genitalia or vulva (mons pubis, labia majora and minora, clitoris, vestibule, vestibular bulb and glands). Tissue preparation, tissue staining, microscopy, hybridisation. Scattered in the cytoplasm are the characteristic clusters of ribosomes and rough ER termed Nissl bodies or Nissl substanceslide 066aView Image. Smooth muscle tissue appears non-striated because of the less orderly arrangement of their filaments. Examine the cross section of the lumbar spinal cord in slide 065-2. Available at theiTunes Storeand for Android users at theGoogle Play Store. This accounts for the name, based on their appearance under the microscope. Do you know why some structures stain blue (basophilic) and others pink (eosinophilic)? Neurons. At one end of the axon are dendrites, and at the other end, the axon forms synaptic connections with a target. Nervous tissue contains two categories of cellsneurons and neuroglia. ("3" in the orientation figure) a molecular layer containing dendrites of the pyramidal cells. - PowerPoint PPT presentation Number of Views: 2727 Avg rating:3.0/5.0 Slides: 14 Provided by: apbrwww5A Category: Tags: histology | nervous | tissue less 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. It monitors and regulates the functions of the body. 2. The nucleus is considered to be the brain of the cell. Bundles of myelinated axons in the brain are called tracts, while bundles of axons in the PNS are called nerves. Title: PowerPoint Presentation Author: Jennifer Ann Jost Last modified by: Jeff Keyte Created Date: 10/29/2003 10:25:53 PM Document presentation . Epithelium is classified by both its cellular morphology and the number of cell layers. In the above image, we can observe only the relatively large, triangular-shaped cell bodies of the pyramidal cells with clearly visible nuclei, parts of the dendrites, and the beginnings of axons. The arrow indicates a morphological type of neuron. Nerve tissue consists of 2 principal types of cells: neurons and supporting cells. The cerebellum consists of an outer cortex of grey matter covering an inner area of white matter, which itself surrounds a deeper layer of grey matter (called the cerebellar nuclei). Many of these astrocytes send out processes that contact and wrap around nearby capillaries, which are also clearly recognizable as tube-shaped segments. In terms of clinical significance, the pyramidal cells of the hippocampus are particularly vulnerable to damage in severe circulatory failure and by anoxia of persistent severe seizures. In the PNS, myelin is produced by Schwann cells, which wrap around the axon. Upon maturation, they are released into the blood, lymph and into secondary lymphoid organs, where they work alongside immune system support cells to carry out a detailed surveillance of potential threats. Recall thatSchwann cells are the glial cells responsible for myelination in the peripheral nervous system. Cells that are well preserved show features characteristic of most neurons: large cell body, large pale nucleus, Nissl substance, and cell processes (most of which are dendrites). The predominant cells visible on the slide are called pyramidal cells (named for their triangular shape). Some sources describe a fourth type of neuron, called an anaxonic neuron. Organelles can be membranous (mitochondria, Golgi apparatus, endoplasmic reticulum) or non-membranous (ribosomes, nucleolus, centrioles). 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"). A third type of connective tissue is embryonic (fetal) tissue, this is a type of primitive tissue present in the embryo and umbilical cord. Table 2 outlines some common characteristics and functions. The tissues of the nervous system can also be divided into grey matter and white matter. Reading time: 28 minutes. 5 Nervous system The introductory part of the chapter is adapted from BC OpenStax Anatomy and Physiology book under the CC BY license. ("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. The basic functional unit of the kidney is the nephron. This traps and removes any inhaled dust, bacteria or foregn substances. 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. 48 Spinal CordWhite Matter (Spinal Cord)View Virtual EM Slide In this field you see several oligodendrocytes, the cells that make myelin in the CNS, surrounded by numerous myelinated axons of various size, cut in cross section. Neuroglia (glial cells) (supporting cells) The blood-brain barrier is a physiological barrier that keeps many substances that circulate in the rest of the body from getting into the central nervous system, restricting what can cross from circulating blood into the CNS. You should also identify the dorsal and ventral horns in slide 65-1N stained with Masson trichrome. 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. The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). Click on human from the drop down list 5. Cardiomyocytes contain actin and myosin filaments just like other muscle cells, but they have some special structural and functional properties. Histology is the science of the microscopic structure of cells, tissues and organs. It is related to both the circulatory system and the immune system. But most everything else cannot, including white blood cells, which are one of the bodys main lines of defense. The medial surface of the section is the posterior portion of the thalamus and a small portion of the cerebral peduncle. ("6" in the orientation figure) a molecular layer containing dendrites of the granule cells. Since tissues are normally colourless, applying a dye to the tissue section allows the cells and their components to be seen under a microscope. Aspects of peripheral nerve embryology and clinically . In this electron micrograph, note some of the features you saw in ventral horn motor neurons with the light microscope, such as the large, pale nucleus, prominent nucleolus, Nissl bodies, dendrites and axon. The choroid plexus is a specialized structure in the ventricles where ependymal cells come in contact with blood vessels and filter and absorb components of the blood to produce cerebrospinal fluid. Each organ of the digestive system has properties that make it specialized for its role in the digestion, absorption and excretion of food. Philadelphia, PA: Lippincott Williams & Wilkins. They are stabilized by ligaments, flexible fibrous bands made of dense regular connective tissue. It is made up of gray matter and white matter. 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. 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. Cells are the tiny living units that form the tissues, organs and structures within the body. Nutrient molecules, such as glucose or amino acids, can pass through the BBB, but other molecules cannot. Histology Complete and Basic Tissues. Neurons are specialized cells that contain a body (soma) and one or more processes ( dendrites, axons ). The cells are laid down on top of dense irregular connective tissue, the basement membrane (BM). Kenhub. The first step in tissue preparation for optic microscopy is fixation. This preserves it into the same state that it had when it was in the body, and thus, keeps it from degrading. Slide 66a View Virtual Slide shows a section of thoracic spinal cord. Correct answer 1. You may see small calcific bodies in part of the hippocampus, which occur as a normal part of the aging process. Nervous tissue is made of cells (neurons and glial cells) and extracellular matrix. Histology - study of tissues Tissue - a collection of similar cells that group together to perform a specialized function. It contains connective tissue, mostly composed of adipocytes. 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. Both will appear grey to the naked eye and under the microscope, due to their lack of myelin. They return this fluid to the heart, passing it through lymphoid organs. celiac, aorticorenal, and superior/inferior mesenteric ganglia). Neurons are the cells considered to be the basis of nervous tissue. It provides somatic motor output to skeletal muscles. Remember, this entire pathway is traveled by cells whose axons may be three feet long! Neurons of the cerebral cortex are of varying shapes and sizes, but the most obvious arepyramidal cells. The renal corpuscle contains the glomerulus, a tuft of fenestrated capillaries which creates an ultrafiltrate of blood. In these slides, dorsal happens to be "up," but you should be able to tell dorsal and ventral horns based on morphology and the cells present rather than the orientation. Based on their functional properties, these are described as either voluntary (skeletal) or involuntary (cardiac and smooth muscle). For an even more detailed view, an electron microscopy can be used. Contents Neuron Nerve cell processes Synapses And impulse transmission The neuroglia Myelin sheath 2 3. The lighter-colored layers on both sides of the axon are myelin. These cells contain contractile filaments (myofibrils) called actin (thin) and myosin (thick). They include hair follicles, skin glands and nails. 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. Depending on the type of cells present (fibroblasts, osteocytes, erythrocytes) and the ECM arrangement, connective tissue can be classified as connective tissue proper or specialized connective tissue. dendritic) processes. Once urine is formed from the ultrafiltrate, it travels through the excretory pathway of tubes, all of which are lined by transitional epithelium with the exception of some parts of the urethra. However, the endothelial cells maintain these junctions in response to signals (via foot processes) from ASTROCYTES. Nicola McLaren MSc Specialised cells (melanocytes, Merkels cells, Langerhans cells) and free nerve endings are found within the epidermis, providing pigmentation, protection and sensation. Read more. Where the axon emerges from the cell body, there is a special region referred to as the axon hillock. nervous tissue is derived from embryonic neuroectoderm The nervous system is divided anatomically into: Central Nervous System (CNS), consisting of the brain and spinal cord. Specialized connective tissue includes the blood, reticular, cartilage, bone and adipose tissue. What is the distinction between the CNS and the PNS? Nervous Tissue DR. DEVI 1 16-4-19 2. Epithelial cells form two important histological structures within the brain; the blood-brain barrier and the choroid plexus. In addition to pyramidal cells, other nuclei seen in these sections may belong to other neurons or to glial cells also present in the cortex. Study with Quizlet and memorize flashcards containing terms like Afferent, efferent, visceral and more. Curated learning paths created by our anatomy experts, 1000s of high quality anatomy illustrations and articles. Lymphatic vessels drain lymph (interstitial fluid) from all the extracellular spaces in the body. It is this myelin, a lipid-rich sheath covering axons, that causes white matter to be lighter in color than grey matter. Based on the number of processes, neurons are classified into multipolar, bipolar and unipolar. Study with Quizlet and memorize flashcards containing terms like Afferent, efferent, visceral and more. Each one reaches out and surrounds an axon to insulate it in myelin. The neuron shown is a multipolar neurons. Each gap is called a node of Ranvier and is important to the way that electrical signals travel down the axon. Within the medulla, most axons will cross over to the opposite hemisphere of the brain from which they originated a process called decussation and then continue within the white matter of the spinal cord, before synapsing with interneurons and lower motor neurons, in the grey matter of the spinal cord. Mescher, A. L. (2013). They are responsible for the computation and . Learn more about the histology of the upper and lower digestive tract. As cells are generally colourless, they need to be stained so that they can be easily viewed under the microscope. One or more cell processes may also be seen emerging from the neuronal perikaryon. A cell is the smallest functional unit of an organism. In the hippocampus orientation Image, observe: In the dentate gyrus orientation Image, observe: The "hilus" is the region where the head of hippocampus abuts the dentate gyrus. 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. The length of the axon between each gap, which is wrapped in myelin, is referred to as an axon segment. Review the organization of gray and white matter in cerebral cortex vs. spinal cord. One of the two types of glial cells found in the PNS is the satellite cell. This is because the liver, among many other things, is the major detoxifying machine 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. These include epithelial cells, fibroblasts, neutrophils, erythrocytes, keratinocytes, chondrocytes just to name a few. Light microscopes (or optical microscopes), use a combination of visible light and lenses to create a magnified image. A group of organs united by similar functions. The cardiovascular system consists of the heart and blood vessels (arteries, arterioles, capillaries, venules, veins). Peripheral ganglia are clusters of nerve cell bodies surrounded by a dense connective tissue capsule. A unity of cells with a similar structure that as a whole express a definite and unique function. . Get an overview of the different types of epithelial tissue: Connective tissue connects, separates and supports the body organs. Thoroughly learn the parts of a cell using our diagrams and cell quizzes! Whereas the manner in which either cell is associated with the axon segment, or segments, that it insulates is different, the means of myelinating an axon segment is mostly the same in the two situations.