1. They can be classified as sensory or autonomic. 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. Histology: An overview: want to learn more about it? Cells are the tiny living units that form the tissues, organs and structures within the body. In general, the brain is composed of an exterior layer of grey matter covering internal areas of white matter, with another internal layer of grey matter in the deepest part of the brain (called the basal nuclei). New York, NY: McGraw-Hill Education. Because information flows through the neuron from dendrites or cell bodies toward the axon, these names are based on the neurons polarity (Figure 2). All of these components work together to provide movement to the body. 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. Review the organization of the spinal cord using your atlas. system is called neurology. Also note these columnar cells lining the ventricles of the brain. Multiple muscle cells are bound by connective tissue into fascicles, and multiple fascicles join to form a muscle belly. 138, 7.18). Any of those processes can function as an axon depending on the conditions at any given time. The latter constitutes the diffuse neuroendocrine system (DNES). Despite their differences, they all have one thing in common; specialized elongated muscle cells, called muscle fibers. This is the reason why people with extensive burns are in life-threatening danger. At a microscopic level, a nephron consists of a renal corpuscle and a series of tubules. Remember, a nerve is a bundle of axons, running in parallel, in the PNS. 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 information we provide is grounded on academic literature and peer-reviewed research. Scattered in the cytoplasm are the characteristic clusters of ribosomes and rough ER termed Nissl bodies or Nissl substanceslide 066aView Image. Learn more about how Pressbooks supports open publishing practices. I love Histology! The first way to classify them is by the number of processes attached to the cell body. Peripheral nerves are bundles of myelinated nerve fibers (axons) wrapped in connective tissue (endo-, peri- and epi- neurium). Did you know that there are special cardiomyocytes in your heart that spontaneously generate impulses to initiate heartbeats? What is the difference between a ganglion and a nucleus? Both respond immunologically to foreign material in the fluid passing through. Click on the tissue and observe. That single axon can branch repeatedly to communicate with many target cells. Neurons are the primary type of cell that most anyone associates with the nervous system. A few other processes provide the same insulation for other axon segments in the area. Remember that the perikaryon is the metabolic support center for each neuron, so, therefore, motor neurons require much larger perikarya. One of the two types of glial cells found in the PNS is the satellite cell. One or more cell processes may also be seen emerging from the neuronal perikaryon. 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. The testes produce male gametes (spermatozoa) via the process of spermatogenesis. Interstitial cells produce testosterone, a hormone that regulates spermatogenesis. In a transverse section of a nerve (Figure 10), single myelinated axons look like little circles organized in bundles called fascicles. The membrane wrapped around the fascicle is called an endoneurium and is made of the loose reticular connective tissue. Kim Bengochea, Regis University, Denver. Lastly, the specimen is stained with hematoxylin and eosin dyes. (PWA), including the SecondLookHistology apps. How about the fact that some cardiomyocytes have the ability to secrete hormones that regulate blood pressure? This nerve was additionally stained with osmium and the membranes of myelin are visible as dark rings. Neurons are characterized by a large cell body or perikaryon containing a large, pale (active, euchromatic) nucleus with a prominentnucleolus. Ependymal cells, which are uniquely located lining the ventricles of the brain the central canal of the spinal cord, are one notable exception. There is a lot more to know about the female reproductive system. 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 Description: Chapter 11 Histology of Nervous Tissue J.F. The arrow indicates a morphological type of neuron. Histology. Name the part of the central nervous system that isdisplayed in this tissue section. Muscle cells have a specialized type of smooth endoplasmic reticulum called sarcoplasmic reticulum, which stores calcium ions. Depending on the number of layers, epithelial tissue is classified into simple (single layered) or stratified (multi-layered). The four main types of stains used in histology are empirical, histochemical, enzyme histochemical and immunohistochemical. Histology (Tissues). Click on human from the drop down list 5. This coronal section includes the hippocampus (hippocampus = sea horse), dentate gyrus, and adjacent temporal lobe gyrus (entorhinal cortex). 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. Review the organization of gray and white matter in cerebral cortex vs. spinal cord. Nervous tissue is composed of two types of cells, neurons and glial cells. The nucleus and cytoplasm of the Schwann cell are on the edge of the myelin sheath. These layers of myelin are many times thicker than the diameters of the axons. 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. The other processes of the neuron are dendrites, which receive information from other neurons at specialized areas of contact called synapses. One is the axon and one the dendrite, forming a straight line. At one end of the axon are dendrites, and at the other end, the axon forms synaptic connections with a target. Pancreatic serous acini secrete digestive enzymes which break down fat, carbohydrates and proteins. 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. Aside from finding efficacious substances, the means of delivery is also crucial. You may see small calcific bodies in part of the hippocampus, which occur as a normal part of the aging process. The edges of this loose enclosure extend toward each other, and one end tucks under the other. Histology - study of tissues Tissue - a collection of similar cells that group together to perform a specialized function. The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The gray matter contains relatively more neuronal and glial perikarya, as well as non-myelinated (e.g. Movement on one side of the body is often controlled by nerve impulses originating on the opposite side of the brain. Reading time: 28 minutes. Pia mater 2. Copyright Fetal tissues are classified into two types: mesenchyme and mucoid (mucous) connective tissue. These hormones regulate a variety of processes, such as metabolism, growth and blood pressure. These cells have a single, long, nerve tract entering the bottom of the cell body. ("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. If the myelin sheath were drawn to scale, the neuron would have to be immensepossibly covering an entire wall of the room in which you are sitting. It acts as insulation, much like the plastic or rubber that is used to insulate electrical wires. Gray matter is mostly made of neuronal bodies, dendrites and glial cells whereas white matter is made primarily out of myelinated axons. Axon diameters can be as small as 1 to 20 micrometers. The organization and morphology of the cells shown is found ONLY in the ventral spinal cord. They include hair follicles, skin glands and nails. Here you will see the Purkinje cell bodies slide 077 View Image. Nueron ppt naseemmeeran 139 views . the peripheral nerves and peripheral ganglia. One could say that the masters of the endocrine glands are the hypophysis (pituitary gland) and hypothalamus, since they regulate all other endocrine organs by way of homeostatic feedback mechanism. 10:10 - 12:05 Muscle Tissue ppt | pdf WEEK 2 Monday, August 22. It is permeable to oxygen, carbon dioxide and other gases, allowing for the occurrence of gas exchange. Body tissues are collections of cells, grouped in the body according to structure and function. 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 contains connective tissue, mostly composed of adipocytes. Figure 1 shows the relationship of these parts to one another. Primarily, the PNS is made up of the axons of neurons whose cell bodies are located within the CNS (within the brain for cranial nerves and the spinal cord for peripheral nerves yet another way to divide the nervous system based on location). The PNS is all neural tissue outside of the CNS, i.e. Author: 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. Philadelphia, Pa: Wolters Kluwer. Contrast the differences in the histological appearance of a pyramidal cell versus a Purkinje cell. Table 2 outlines some common characteristics and functions. It provides somatic motor output to skeletal muscles. 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). Look at the margins of the ventricle at higher magnification and note that it is entirely lined by ependymal cells. The branch of medical science that deals with the. It consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus. You may be able to see subtle differences in the distribution of cell types in rather loosely demarcated layers. 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"). Register now With the exception of the unipolar sensory ganglion cells, and the two specific bipolar cells mentioned above, all other neurons are multipolar. Specialized connective tissue includes the blood, reticular, cartilage, bone and adipose tissue. All Rights Reserved. In contrast, electron microscopes work by emitting parallel beams of electrons onto the sample being observed, resulting in higher resolutions.
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nervous tissue histology ppt