nervous tissue histology ppt

It consists of a few cells and an abundance of extracellular matrix. A unity of cells with a similar structure that as a whole express a definite and unique function. Astrocytes - Technically, the junctions between endothelial cells constitute the actual "barrier." The delicate meshwork of dendritic processes and nerve fibers (axons) lying between cells in the gray matter is called the neuropil. celiac, aorticorenal, and superior/inferior mesenteric ganglia). Myelin is lipid-rich, and on gross inspection appears white. I would honestly say that Kenhub cut my study time in half. 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. Please support theSecondLook initiative with a donation to ourMichigan MedicineSecondLook Donation Champaign(link is external). How is this different in the spinal cord? At a microscopic level, a nephron consists of a renal corpuscle and a series of tubules. 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. During development, the glial cell is loosely or incompletely wrapped around the axon (Figure 6). Neuroglia. Health Information Technology & Services. They are large, easily distinguishable, and have an extensive dendritic tree that is not visible in typical histology. Thus are essential for maintaining homeostasis of the body. A single axon (often called a nerve fiber) leaves the perikaryon and transmits neural signals to other neurons or to the effectororgan (e.g., skeletal muscles) via synapses. Uploaded on Jun 06, 2013 Elina + Follow cuboidal epithelium water loss Schwann cells are different than oligodendrocytes, in that a Schwann cell wraps around a portion of only one axon segment and no others. One or more cell processes may also be seen emerging from the neuronal perikaryon. Some ways in which they support neurons in the central nervous system are by maintaining the concentration of chemicals in the extracellular space, removing excess signaling molecules, reacting to tissue damage, and contributing to the blood-brain barrier (BBB). Connective tissue proper is further subdivided into loose connective tissue, mostly found in internal organs as supporting tissue stroma, and dense connective tissue, which can be regular (tendons, ligaments) or irregular (dermis of the skin, organ capsules). Use the virtual slide of the hippocampal region to study the ependymal cell lining of the choroid plexus. Under light microscopy, skeletal and cardiac muscles appear striated due to the parallel arrangement of their contractile filaments into repeating units called sarcomeres. This neuron provides preganglionic visceral motor output to sympathetic ganglia - Even though the cord is oriented "sideways," you should still be able to identify this cell as being in the intermediolateral cell column in the lateral extension of the ventral horn where pregagnglionic sympathetic visceral motor neurons are found. Bipolar cells are not very common. At the end of the axon is the axon terminal, where there are usually several branches extending toward the target cell, each of which ends in an enlargement called a synaptic end bulb. They are considered to be supporting cells, and many functions are directed at helping neurons complete their function for communication. This is the final course in the series that will explore special stains used in the clinical histology laboratory. The insulation for axons in the nervous system is provided by glial cells, oligodendrocytes in the CNS, and Schwann cells in the PNS. A few other processes provide the same insulation for other axon segments in the area. Many types of glial cells require special histological stains and cant be unambiguously identified in regular H&E-stained histological slides. This coronal section includes the hippocampus (hippocampus = sea horse), dentate gyrus, and adjacent temporal lobe gyrus (entorhinal cortex). They are responsible for the computation and . Electron microscopy (EM) is a more modern form of microscopy that provides a much higher magnification and high resolution images. Bundles of myelinated axons in the brain are called tracts, while bundles of axons in the PNS are called nerves. 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). These sections are then mounted on a glass slide, using a mounting medium as an adhesive. A group of neuronal cell bodies is called a nucleus in the brain or spinal cord, and a ganglion in the PNS. Want to create or adapt books like this? It is permeable to oxygen, carbon dioxide and other gases, allowing for the occurrence of gas exchange. Click on a question to reveal the answer. This ground substance, also referred to as Wharthons jelly, provides insulation and protection to the blood vessels of the umbilical cord. Multiple muscle cells are bound by connective tissue into fascicles, and multiple fascicles join to form a muscle belly. Because of this, ependymal cells can be considered a component of the BBB, or a place where the BBB breaks down. All cells contain cytoplasm, are surrounded by a membrane, and contain a variety of structures and organelles. Remember, a nerve is a bundle of axons, running in parallel, in the PNS. This preserves it into the same state that it had when it was in the body, and thus, keeps it from degrading. Examine the boundary between molecular and granule cell layers. Click on human from the drop down list 5. This accounts for the name, based on their appearance under the microscope. The neuron is the structural and functional/electrically excitable unit of the nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). There is a lot more to know about the female reproductive system. The nervous system is responsible for the control of the body and the communication among its parts. The small gap in the myelin sheath that occurs between adjacent Schwann cells is called a node of Ranvier. When macrophages encounter diseased or damaged cells in the rest of the body, they ingest and digest those cells or the pathogens that cause disease. Lastly, the specimen is stained with hematoxylin and eosin dyes. Microglia are the cells in the CNS that can do this in normal, healthy tissue, and they are therefore also referred to as CNS-resident macrophages. As cells are generally colourless, they need to be stained so that they can be easily viewed under the microscope. Histology of Nervous TissueNervous system ppt #2. The PNS encompasses all nervous tissue outside of bony structures, and includes all peripheral and cranial nerves, plexuses, and ganglia. The length of the axon between each gap, which is wrapped in myelin, is referred to as an axon segment. There are 6 classically recognized layers of the cortex: Pyramidal cells in layers III and V tend to be larger because their axons contribute to efferent projections that extend to other regions of the CNS pyramidal neurons in layer V of motor cortices send projections all the way down to motor neurons in the spinal cord! Type II pneumocytes are also important because they secrete surfactant which prevents the lungs from collapsing. Slide 077 20XCerebellum white and grey matter H&E View Virtual Slide, Slide 077 40XCerebellum molecular layer, Purkinje cell bodies H&E View Virtual Slide, Slide 077a Cerebellum luxol blue cross View Virtual Slide. 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. Microglia are, as the name implies, smaller than most of the other glial cells. 5 Nervous system The introductory part of the chapter is adapted from BC OpenStax Anatomy and Physiology book under the CC BY license. Grounded on academic literature and research, validated by experts, and trusted by more than 2 million users. As a muscle contracts, its tendon transmits the force to the bone, pulling on it and causing movement in the associated synovial joint. as white matter? To visualize this dendritic tree, an osmium stain can be used. 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 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. After preparation, the tissue is stained. Together these organs provide the ability of reproduction and sexual intercourse. The product is the magnifying power of the objective (4x, 10x, 20x, 40x or 100x) multiplied by the power of the ocular lenses (10x). Because information flows through the neuron from dendrites or cell bodies toward the axon, these names are based on the neurons polarity (Figure 2). The renal corpuscle contains the glomerulus, a tuft of fenestrated capillaries which creates an ultrafiltrate of blood. This is a tapering of the cell body toward the axon fiber. 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. This method is based on the ability of single stranded DNA or RNA to merge with a complementary strand and build a hybrid which is then detected due to the label. Reading time: 28 minutes. The first step in tissue preparation for optic microscopy is fixation. Unipolar cells are exclusively sensory neurons and have two unique characteristics. Dendrites of Purkinje cells extend deep into the molecular layer, while the axons of Purkinje cells cross the granular layer and join other nerve fibers in the interior white matter of the cerebellum. Ongoing research pursues an expanded role that glial cells might play in signaling, but neurons are still considered the basis of this function. Hair follicles are invaginations of the epidermis that contain rapidly proliferating and keratinizing cells responsible for the production and growth of hair. Each one reaches out and surrounds an axon to insulate it in myelin. Chapter 12Nervous Tissue. Controls and integrates all body activities. Alveoli are the primary site of gas exchange. Interstitial cells produce testosterone, a hormone that regulates spermatogenesis. Some of the proteins help to hold the layers of the glial cell membrane closely together.The appearance of the myelin sheath can be thought of as similar to the pastry wrapped around a hot dog. In this article, we will introduce you to the microscopic world of histology. For example, nerves can be classified based on their function. Based on morphology, epithelial cells can be either squamous (flat), cuboid (cube) or columnar (rectangular). Click on the tissue and observe. Author: The medial surface of the section is the posterior portion of the thalamus and a small portion of the cerebral peduncle. Histology (Tissues). Ross, H. M, Pawlina, W. (2011). Junquieras Basic Histology (13th ed.). Contrast the differences in the histological appearance of a pyramidal cell versus a Purkinje cell. Unipolar neurons have only one process emerging from the cell body which causes them to appear T-shaped. With the exception of the unipolar sensory ganglion cells, and the two specific bipolar cells mentioned above, all other neurons are multipolar. They are stabilized by ligaments, flexible fibrous bands made of dense regular connective tissue. Both will appear grey to the naked eye and under the microscope, due to their lack of myelin. Then, get ready to test your knowledge! Muscle cells have a specialized type of smooth endoplasmic reticulum called sarcoplasmic reticulum, which stores calcium ions. 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. It is this myelin, a lipid-rich sheath covering axons, that causes white matter to be lighter in color than grey matter. One oligodendrocyte will provide the myelin for multiple axon segments, either for the same axon or for separate axons. The alimentary canal is a tube extending from the mouth to the anus that serves as a channel for food and water to be digested, their nutrients absorbed and indigestible portions excreted. But most everything else cannot, including white blood cells, which are one of the bodys main lines of defense. They are electrically active and release chemical signals to target cells. Remember that the perikaryon is the metabolic support center for each neuron, so, therefore, motor neurons require much larger perikarya. As such, nerves do not contain neural cell bodies. These vibrate to produce sound as air passes through them. 1:00 - 1:50 Nervous Tissue ppt | pdf | lecture recording (for both hours) 2:05 - 2:55 Connective Tissue ppt | pdf. Glial cells, or neuroglia or simply glia, are the other type of cell found in nervous tissue. Peripheral nerves are analogous with neural tracts of the CNS. They also have cilia on their apical surface to help move the CSF through the ventricular space. Name this exception. Continue your learning with these resources. The Schwann cells (in the peripheral nerves) and the satellite cells (in the ganglia) are glial cells (supporting cells) of the PNS. This traps and removes any inhaled dust, bacteria or foregn substances. Glial cells, or glia, are known to play a supporting role for nervous tissue. Because of this, only specific types of molecules can enter the CNS. They are highly specialized to transmit nerve impulses. Nervous tissue is made of cells (neurons and glial cells) and extracellular matrix. . On a longitudinal section, cardiomyocytes appear branched, joined together by specialized junctions called intercalated discs which allow them to quickly exchange electrical impulses and work as a syncytium. DNA is condensed and coiled up into chromosomes. All cells are enveloped by a semipermeable two-layered membrane, which serves as a dynamic medium for the cells interaction with the external environment. The lighter-colored layers on both sides of the axon are myelin. It is the axon that propagates the nerve impulse, which is communicated to one or more cells. 2023 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. Read more. Much like the male, the female reproductive system is also designed for reproduction and sexual pleasure. Eroschenko, V. P. (2017). The layers of the blood-air barrier comprise of type I pneumocytes, basement membrane and endothelial cells of the capillaries. 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. They return this fluid to the heart, passing it through lymphoid organs. The neuronal bodies within the grey matter are organized into layers (laminae). Scattered in the cytoplasm are the characteristic clusters of ribosomes and rough ER termed Nissl bodies or Nissl substanceslide 066aView Image. Review the organization of the spinal cord using your atlas. Your donation will enable us to update all existingSecondLook resources and to transform them into completely free Progressive Web Applications (PWA), including theSecondLookHistology apps. 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 Unlike the highly organized cerebellar cortex, the cerebral cortex appears to be less well-organized when viewed with the light microscope. They are considered part of the mononuclear phagocytic system and will proliferate and become actively phagocytic in regions of injury and/or inflammation. Remember that the perikaryon is the metabolic support center for each neuron, so, therefore, motor neurons require much larger perikarya. The skin is both a medium for interaction with the environment and a barrier, protecting us from outside microbes and chemicals, changes in temperature and dehydration. Histology - study of tissues Tissue - a collection of similar cells that group together to perform a specialized function. Neurons are the primary type of cell that most anyone associates with the nervous system. Nutrient molecules, such as glucose or amino acids, can pass through the BBB, but other molecules cannot. And there are many different types of neurons. With one exception, neurons such as this (though not necessarily this large) are found in ALL areas of the nervous system. True unipolar cells are only found in invertebrate animals, so the unipolar cells in humans are more appropriately called pseudo-unipolar cells. Histology. If you were to look at some bones on a skeleton, youd see a greyish rigid mass with some bumps and depressions. Nervous tissue histology 1. Neurons are important, but without glial support they would not be able to perform their function. Nervous tissue is made up of just 2 types of cells: Neurons. Diffuse lymphoid tissues and lymphatic nodules are non-encapsulated accumulations of lymphoid tissue found in locations such as the alimentary, respiratory and genitourinary tracts. The epidermis is a keratinized stratified squamous epithelium mostly made out of keratinocytes. Remember, this entire pathway is traveled by cells whose axons may be three feet long! It provides preganglionic visceral motor output to sympathetic ganglia. 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. Thoroughly learn the parts of a cell using our diagrams and cell quizzes! All of this is surrounded by three connective tissue membranes (meninges): dura, arachnoid and the pia mater. A third type of connective tissue is embryonic (fetal) tissue, this is a type of primitive tissue present in the embryo and umbilical cord. Different regions of the nervous system have distinct histological characteristics that make them easily recognizable, under the microscope. The glial cell is wrapped around the axon several times with little to no cytoplasm between the glial cell layers. Movement on one side of the body is often controlled by nerve impulses originating on the opposite side of the brain. I love Anatomy. Fetal tissues are classified into two types: mesenchyme and mucoid (mucous) connective tissue. Like a few other parts of the body, the brain has a privileged blood supply. dendritic) processes. Wheaters functional histology: A text and colour atlas. The main effector cells of the lymphatic system are the immune system cells. EM works by emitting parallel beams of electrons onto the tissue sample. Did you know that the only thing preventing all the water in your body from leaking out through your skin are the tight junctions between the keratinocytes? 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. This is why doctors must take extra caution when prescribing medication to these people. Neurons are specialized cells that contain a body (soma) and one or more processes ( dendrites, axons ). Also found in CNS tissue is the oligodendrocyte, sometimes called just oligo, which is the glial cell type that insulates axons in the CNS. They have rectangular bodies and many dendrite like projections stemming from their shorter sides. Sertoli cells prevent the immune system from attacking and destroying the spermatozoa. 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"). The inner edge wraps around the axon, creating several layers, and the other edge closes around the outside so that the axon is completely enclosed.Myelin sheaths can extend for one or two millimeters, depending on the diameter of the axon. They can be classified by many different criteria. For example, a multipolar neuron that has a very important role to play in a part of the brain called the cerebellum is known as a Purkinje (commonly pronounced per-KIN-gee) cell. All spaces are occupied either by the processes of neurons or glia or by capillaries (these capillaries are somewhat swollen here because the tissue was fixed by perfusion). These exclusively contain neurons with a pseudounipolar neuronal arrangement. Some sources describe a fourth type of neuron, called an anaxonic neuron. Nervous tissue consists of two cells: nerve cells or neurons and glial cells, which helps transmit nerve impulses and also provides nutrients to neurons. adipose tissue, gastrointestinal tract, cardiovascular system). The organization and morphology of the cells shown is found ONLY in the ventral spinal cord. This is done by the use of a complementary nucleotide probe, which contains a radioactive or fluorescent label. Spermatozoa pass from the testis into the epithelial lined epididymis and ductus (vas) deferens via efferent ductules, then into the ejaculatory duct, which merges with the urethra. Gordana Sendi MD

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