New York, NY: McGraw-Hill Education. A group of neuronal cell bodies is called a nucleus in the brain or spinal cord, and a ganglion in the PNS. Bone tissue is a specialized type of connective tissue that contains cells (osteoblasts, osteocytes, osteoclasts), fibers (collagen type I) and mineralized extracellular matrix. 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). 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. Examine the cross section of the lumbar spinal cord in slide 065-2. Nails are plates of proliferating keratinized cells that, similar to hair, contain hard keratin. It is named after the anatomist who discovered it (Jan Evangilista Purkinje, 17871869). The first step in tissue preparation for optic microscopy is fixation. They are highly specialized to transmit nerve impulses. The cardiovascular system consists of the heart and blood vessels (arteries, arterioles, capillaries, venules, veins). Please support theSecondLook initiative with a donation to ourMichigan MedicineSecondLook Donation Champaign(link is external). Type II pneumocytes are also important because they secrete surfactant which prevents the lungs from collapsing. Review diagrams illustrating the morphology of neurons in your textbooks. The primary purpose of this article is to evaluate the histology of peripheral nervous tissue. 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. Four main groups of tissues Epithelial Connective Muscle Nervous tissue. Neuronal processes form connections (synapses) with each other and with other cell types, in order to exchange electrical signals. The male reproductive system consist of the internal genitalia (testes, genital ducts and accessory genital glands) and external genitalia (penis and scrotum). The ovary is actually an organ homologous to the male testis, it gives rise to the gametes (ova) and steroid hormones (estrogen, progesterone). Click on launch activity 2. For an even more detailed view, an electron microscopy can be used. Remember, a nerve is a bundle of axons, running in parallel, in the PNS. Alveoli are the primary site of gas exchange. adipose tissue, gastrointestinal tract, cardiovascular system). It consists of widely separated mesenchymal cells and ground substance with an abundance of hyaluronic acid. Click on explore at the bottom of the page 3. Histology Copyright by Malgosia Wilk-Blaszczak. It is categorised as skeletal, cardiac or smooth. The cells are laid down on top of dense irregular connective tissue, the basement membrane (BM). Unipolar cells are exclusively sensory neurons and have two unique characteristics. The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). These glial cells appear similar to epithelial cells, making a single layer of cells with little intracellular space and tight connections between adjacent cells. These cells contain contractile filaments (myofibrils) called actin (thin) and myosin (thick). While their origin is not conclusively determined, their function is related to what macrophages do in the rest of the body. as white matter? It provides somatic motor output to skeletal muscles. I would honestly say that Kenhub cut my study time in half. The small gap in the myelin sheath that occurs between adjacent Schwann cells is called a node of Ranvier. The Neuron Special property of irritability & conductivity Nerve cells are capable of receiving the . Lastly, the specimen is stained with hematoxylin and eosin dyes. Friday, August 26 The lateral extension of the ventral horn slide 065-2 contains relatively large, multipolar visceral motor neurons of the intermediolateral cell column that extends from levels T1 through L2 of the spinal cord. This preserves it into the same state that it had when it was in the body, and thus, keeps it from degrading. The lipids are essentially the phospholipids of the glial cell membrane. It also helps us understand the relationship between structure and function. Both neurons and glia have fine processes projecting from the cell body, which generally cannot be resolved in the light microscope without special staining techniques. Kim Bengochea, Regis University, Denver. Tissues join together in different arrangements to form our body organs. Histology 5.ppt CT, Bone Histology 5 supplement.ppt : Histology 6.ppt Muscle: Histology Lab 4.doc Muscle and Start of Nervous Tissue: Histology 7.ppt M, Nervous: Histology Lab 5.doc Nervous (continued), Digestion Start: Histology 8.ppt Nervous : Histology 9.ppt : Histology 10.ppt Nervous: Histology11.ppt CNS, Digestion : Histology 12.ppt . Neurons are important, but without glial support they would not be able to perform their function. Histology Complete and Basic Tissues. The outer cerebellar cortex, shown in Figure 8, is tightly folded and has three distinct layers: Purkinje cells are typically arranged in a single row between the exterior molecular and interior granular layers. Register now This ground substance, also referred to as Wharthons jelly, provides insulation and protection to the blood vessels of the umbilical cord. Still deeper is the white matter slide 077 View Image of the cerebellum, which contains nerve fibers, neuroglial cells, small blood vessels, but no neuronal cell bodies. There are more tissues on the website than you are responsible for. Describe the organization and understand some of the basic functions of regions of the: Observe the 3-layered organization of the, Outer plexiform (molecular) layer: sparse neurons and glia, Outer granular layer: small pyramidal and stellate neurons, Outer pyramidal layer: moderate sized pyramidal neurons (should be able to see these in either, Inner granular layer: densely packed stellate neurons (usually the numerous processes arent visible, but there are lots of nuclei reflecting the cell density), Ganglionic orinner pyramidal layer: large pyramidal neurons (should be able to see these in either, Multiform cell layer: mixture of small pyramidal and stellate neurons. Based on the number of processes, neurons are classified into multipolar, bipolar and unipolar. There is a lot more to know about the female reproductive system. Many types of glial cells require special histological stains and cant be unambiguously identified in regular H&E-stained histological slides. True unipolar cells are only found in invertebrate animals, so the unipolar cells in humans are more appropriately called pseudo-unipolar cells. 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. Structure of a Neuron. Aside from finding efficacious substances, the means of delivery is also crucial. Neuroglia. 10:10 - 12:05 Muscle Tissue ppt | pdf WEEK 2 Monday, August 22. A unity of tissues with a more complex set of functions, defined by the combination of structure and function of the comprising tissues. 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. Neurons are the primary type of cell that most anyone associates with the nervous system. But most everything else cannot, including white blood cells, which are one of the bodys main lines of defense. Nervous tissue. 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. thyroid, ovaries, suprarenal) and individual hormone-secreting cells found in many organs of the body (e.g. . Description: Chapter 11 Histology of Nervous Tissue J.F. Movement on one side of the body is often controlled by nerve impulses originating on the opposite side of the brain. . 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. All rights reserved. NERVOUS TISSUE Nervous tissue consists of two groups of cell types: Nerve cells (Neurons) Neuroglia. Nervous tissue. Cells are the tiny living units that form the tissues, organs and structures within the body. While this barrier protects the CNS from exposure to toxic or pathogenic substances, it also keeps out the cells that could protect the brain and spinal cord from disease and damage. Axon diameters can be as small as 1 to 20 micrometers. The epidermis (epithelium) and dermis (connective tissue) compose the skin. Myelin, however, is more than just the membrane of the glial cell. Cells come together with extracellular matrix (a jelly-like fluid) to form the four types of tissues found in the human body: epithelial, connective, muscle and nervous. 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. Also found in CNS tissue is the oligodendrocyte, sometimes called just oligo, which is the glial cell type that insulates axons in the CNS. 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. The main effector cells of the lymphatic system are the immune system cells. Glial cells, such as astrocytes, oligodendrocytes, Schwann cells and others, provide support, nourishment, myelination and protection to neurons. Peripheral nerves are analogous with neural tracts of the CNS. Wheaters functional histology: A text and colour atlas. Bipolar cells are not very common. A few other processes provide the same insulation for other axon segments in the area. Eroschenko, V. P. (2017). Slides include types of epithelial, connective, nervous, and muscle tissue and is ideal for an anatomy and physiology course. Myelin is a fatty substance that makes the axon appear white. Histology. The dermis is a layer of connective tissue that contains collagen fibers, blood vessels, lymphatics and nerve endings. As cells are generally colourless, they need to be stained so that they can be easily viewed under the microscope. Muscle cells have a specialized type of smooth endoplasmic reticulum called sarcoplasmic reticulum, which stores calcium ions. This traps and removes any inhaled dust, bacteria or foregn substances. ("6" in the orientation figure) a molecular layer containing dendrites of the granule cells. It is composed of densely packed epithelial cells with only a little extracellular matrix (ECM). The predominant cells visible on the slide are called pyramidal cells (named for their triangular shape). These hormones regulate a variety of processes, such as metabolism, growth and blood pressure. Human anatomy is pretty straightforward. Based on their functional properties, these are described as either voluntary (skeletal) or involuntary (cardiac and smooth muscle). Some sources describe a fourth type of neuron, called an anaxonic neuron. Cerebral cortex 3. Examine the layered organization of the cerebral cortex usingslide 76stained withluxol blue/cresyl violet[orientation](which stains white matter tracts and cell bodies) ortoluidine blue and eosin[orientation](TB&E, toluidine blue stains the nuclei and RER of cells whereas eosin stains membranes and axon tracts). The function of myelin will be discussed below. The cells here arepreganglionic sympathetic 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. Ongoing research into these cells, although not entirely conclusive, suggests that they may originate as white blood cells, called macrophages, that become part of the CNS during early development. The endocrine system is divided into major endocrine glands (e.g. They can be classified by many different criteria. They have one axon and two or more dendrites (usually many more). 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. All of these features give muscles the ability to contract and perform various functions, such as movement of the extremities (skeletal muscle), peristalsis of the gastrointestinal tract (smooth muscle) and beating of the heart (cardiac muscle). The glial cell is wrapped around the axon several times with little to no cytoplasm between the glial cell layers. Myelin is lipid-rich, and on gross inspection appears white. Remember, this entire pathway is traveled by cells whose axons may be three feet long! 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: An overview: want to learn more about it? Specialised cells (melanocytes, Merkels cells, Langerhans cells) and free nerve endings are found within the epidermis, providing pigmentation, protection and sensation. Chapter 1 The Cell Chapter 2 Epithelium Chapter 3 Connective Tissue Chapter 4 Muscle Chapter 5 Cartilage and Bone Chapter 6 Nervous Tissue Chapter 7 Peripheral Blood Chapter 8 Hematopoiesis Organ Systems 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. Nervous tissue histology 1. The musculoskeletal system consists of hard tissues (bones, joints, cartilage) and soft tissues (muscles, tendons, ligaments). For oligodendrocytes, the rest of the cell is separate from the myelin sheath as a cell process extends back toward the cell body. These exclusively contain neurons with a pseudounipolar neuronal arrangement. This is the reason why people with extensive burns are in life-threatening danger. Some neurons are named on the basis of those sorts of classifications (Figure 3). 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. Epithelial tissue can cover external surfaces (skin), line the inside of hollow organs (intestines) or form glands. Schwann cells are different than oligodendrocytes, in that a Schwann cell wraps around a portion of only one axon segment and no others. The axon projects from the dendrite endings, past the cell body in a ganglion, and into the central nervous system. Basic nervous tissue staining mechanisms and classification of nervous tissue elements will be discussed. Because of the privileged blood supply inherent in the BBB, the extracellular space in nervous tissue does not easily exchange components with the blood. Most substances that cross the wall of a blood vessel into the CNS must do so through an active transport process. 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). Neuroglia. What anatomical feature explains this phenomenon? 4. The sample on the slide below (Figure 7) was taken from the motor cortex, an area of the frontal lobe of the cerebral cortex that is involved in the conscious planning and execution of voluntary muscle movement. The arrow indicates a morphological type of neuron. Satellite cells are found in sensory and autonomic ganglia, where they surround the cell bodies of neurons. It relays sensory input to other neurons in the spinal cord. Some well-known lymphatic nodules include; the tonsils, Peyers patches and vermiform appendix. 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. Organelles can be membranous (mitochondria, Golgi apparatus, endoplasmic reticulum) or non-membranous (ribosomes, nucleolus, centrioles). Since tissues are normally colourless, applying a dye to the tissue section allows the cells and their components to be seen under a microscope. Name this exception. They are responsible for the computation and . A key difference between myelin and the insulation on a wire is that there are gaps in the myelin covering of an axon. The ECM of nervous tissue is rich in ground substance, with little to no protein fibers. 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). Examine the boundary between molecular and granule cell layers. Information flows through a neuron from the dendrites, across the cell body, and down the axon. Glial cells, or glia, are known to play a supporting role for nervous tissue. The nucleus and cytoplasm of the Schwann cell are on the edge of the myelin sheath. Epithelium is classified by both its cellular morphology and the number of cell layers. Read more. Nervous tissue is made of cells (neurons and glial cells) and extracellular matrix. With one exception, neurons such as this (though not necessarily this large) are found in ALL areas of the nervous system. They are considered part of the mononuclear phagocytic system and will proliferate and become actively phagocytic in regions of injury and/or inflammation. Nervous or the nerve tissue is the main tissue of our nervous system. The BBB also makes it harder for pharmaceuticals to be developed that can affect the nervous system. 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 neuronal bodies within the grey matter are organized into layers (laminae). Ross, H. M, Pawlina, W. (2011). The three-dimensional shape of these cells makes the immense numbers of connections within the nervous system possible. 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. The other processes of the neuron are dendrites, which receive information from other neurons at specialized areas of contact called synapses. 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. 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. Within the axon hillock, the cytoplasm changes to a solution of limited components called axoplasm. Read more. This is because the liver, among many other things, is the major detoxifying machine of the body. The CNS contains the brain and spinal cord. Where the axon emerges from the cell body, there is a special region referred to as the axon hillock. Much like the male, the female reproductive system is also designed for reproduction and sexual pleasure. Calcific bodies are present in the choroid plexus, another common site of accumulation as the years pass. Nervous tissue contains two basic categories of cells: neurons and support cells (glia). But what makes neurons special is that they have many extensions of their cell membranes, which are generally referred to as processes. The cell body contains the nucleus and most of the major organelles. In a transverse section of a nerve (Figure 10), single myelinated axons look like little circles organized in bundles called fascicles. Slide 66a View Virtual Slide shows a section of thoracic spinal cord. Wednesday, August 24. Recall thatSchwann cells are the glial cells responsible for myelination in the peripheral nervous system. In general, where in the brain can grey matter be found? Microglia are, as the name implies, smaller than most of the other glial cells. There are six types of glial cells. Spleen and lymph node histology shows an encapsulated meshwork of fibres, in which immune system cells sit. The layers of the blood-air barrier comprise of type I pneumocytes, basement membrane and endothelial cells of the capillaries. Learning anatomy is a massive undertaking, and we're here to help you pass with flying colours. Health Information Technology & Services. Other blotting techniques include Southern blot, Western blot, Far-Western blot, Southwestern blot, Eastern blot, Far-Eastern blot, Northern blot, Reverse Northern blot and Dot blot. Click on a question to reveal the answer. 2. Histology of Nervous Tissue PROF. DR. FAUZIAH OTHMAN DEPT OF HUMAN ANATOMY Feature of nerves tissue Type of cell: neuron & neuroglia General feature of neuron Type of 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. Neurons. They are electrically active and release chemical signals to target cells. This nerve was additionally stained with osmium and the membranes of myelin are visible as dark rings. The first way to classify them is by the number of processes attached to the cell body. Nervous tissue consists of two cells: nerve cells or neurons and glial cells, which helps transmit nerve impulses and also provides nutrients to neurons. The excretory system includes the kidneys, ureters, urinary bladder and urethra. The medial surface of the section is the posterior portion of the thalamus and a small portion of the cerebral peduncle. 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. Muscle attaches to bone via tendons; bundles of dense regular connective tissue made out of many collagen type I fibers. Histology (Tissues). Above the temporal (ventral or inferior) horn of the lateral ventricle the lateral geniculate nucleus is present. This system delivers oxygenated blood from the heart to the tissues, and returns deoxygenated blood from the tissues back to the heart and lungs. 3. It consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus. 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). Both will appear grey to the naked eye and under the microscope, due to their lack of myelin. behaviors, memories, and movements. 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. 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. Histology of Nervous Tissue Feature of nerves tissue Type of cell: neuron & neuroglia General feature of neuron Type of Expert Help Astrocytes - Technically, the junctions between endothelial cells constitute the actual "barrier." Skin appendages are derivatives of the epidermis. Learn more about how Pressbooks supports open publishing practices. Did you know that chronic alcoholics have a lot more smooth endoplasmic reticulum concentrations in their hepatocytes? Thus are essential for maintaining homeostasis of the body. Optic microscopy, also known as light microscopy, uses light from the visible spectrum and combines it with multiple lenses to create a magnified image. It provides preganglionic visceral motor output to sympathetic ganglia. Mesenchymal cells are undifferentiated cells, which means they are capable of differentiating into any type of connective tissue cells (fibroblasts, osteoblasts, adipocytes etc.). Tissue preparation, tissue staining, microscopy, hybridisation. A group of organs united by similar functions. The dendritic tree and axon of each Purkinje cell can only be seen in thicker sections stained with special silver stains. When viewing the microscopic anatomy of the ovary, we can see that it consists of a surface germinal epithelium (capsule), ovarian follicles (cortex) and connective tissue (capsule, cortex medulla).
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