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76-551: [REDACTED] Look up tissue in Wiktionary, the free dictionary. Tissue may refer to: Biology [ edit ] Tissue (biology) , an ensemble of similar (or dissimilar in structure but same in origin) cells that together carry out a specific function Triphosa haesitata , a species of geometer moth ("tissue moth") found in North America Triphosa dubitata ,

152-493: A thinly sectioned sample to produce an observable image. Other major types of microscopes are the fluorescence microscope , electron microscope (both the transmission electron microscope and the scanning electron microscope ) and various types of scanning probe microscopes . Although objects resembling lenses date back 4,000 years and there are Greek accounts of the optical properties of water-filled spheres (5th century BC) followed by many centuries of writings on optics,

228-601: A 0.1 nm level of resolution, detailed views of viruses (20 – 300 nm) and a strand of DNA (2 nm in width) can be obtained. In contrast, the SEM has raster coils to scan the surface of bulk objects with a fine electron beam. Therefore, the specimen do not necessarily need to be sectioned, but coating with a nanometric metal or carbon layer may be needed for nonconductive samples. SEM allows fast surface imaging of samples, possibly in thin water vapor to prevent drying. The different types of scanning probe microscopes arise from

304-437: A compound light microscope depends on the quality and correct use of the condensor lens system to focus light on the specimen and the objective lens to capture the light from the specimen and form an image. Early instruments were limited until this principle was fully appreciated and developed from the late 19th to very early 20th century, and until electric lamps were available as light sources. In 1893 August Köhler developed

380-420: A fine probe, usually of silicon or silicon nitride, attached to a cantilever; the probe is scanned over the surface of the sample, and the forces that cause an interaction between the probe and the surface of the sample are measured and mapped. A near-field scanning optical microscope is similar to an AFM but its probe consists of a light source in an optical fiber covered with a tip that has usually an aperture for

456-743: A function is called cellular differentiation . Cells of meristematic tissue differentiate to form different types of permanent tissues. There are 2 types of permanent tissues: Simple permanent tissue is a group of cells which are similar in origin, structure, and function. They are of three types: Parenchyma (Greek, para – 'beside'; enchyma– infusion – 'tissue') is the bulk of a substance. In plants, it consists of relatively unspecialized living cells with thin cell walls that are usually loosely packed so that intercellular spaces are found between cells of this tissue. These are generally isodiametric, in shape. They contain small number of vacuoles or sometimes they even may not contain any vacuole. Even if they do so

532-604: A function of providing mechanical support. They do not have inter-cellular spaces between them. Lignin deposition is so thick that the cell walls become stronger, rigid and impermeable to water, which are also known as a stone cells or sclereids. These tissues are mainly of two types: sclerenchyma fiber and sclereids. Sclerenchyma fiber cells have a narrow lumen and are long, narrow and unicellular. Fibers are elongated cells that are strong and flexible, often used in ropes. Sclereids have extremely thick cell walls and are brittle, and are found in nutshells and legumes. The entire surface of

608-584: A key principle of sample illumination, Köhler illumination , which is central to achieving the theoretical limits of resolution for the light microscope. This method of sample illumination produces even lighting and overcomes the limited contrast and resolution imposed by early techniques of sample illumination. Further developments in sample illumination came from the discovery of phase contrast by Frits Zernike in 1953, and differential interference contrast illumination by Georges Nomarski in 1955; both of which allow imaging of unstained, transparent samples. In

684-483: A molecular level in both live and fixed samples. The rise of fluorescence microscopy drove the development of a major modern microscope design, the confocal microscope . The principle was patented in 1957 by Marvin Minsky , although laser technology limited practical application of the technique. It was not until 1978 when Thomas and Christoph Cremer developed the first practical confocal laser scanning microscope and

760-409: A sample and produce images, either by sending a beam of light or electrons through a sample in its optical path , by detecting photon emissions from a sample, or by scanning across and a short distance from the surface of a sample using a probe. The most common microscope (and the first to be invented) is the optical microscope , which uses lenses to refract visible light that passed through

836-436: A sample. In a TEM the electrons pass through the sample, analogous to basic optical microscopy . This requires careful sample preparation, since electrons are scattered strongly by most materials. The samples must also be very thin (below 100 nm) in order for the electrons to pass through it. Cross-sections of cells stained with osmium and heavy metals reveal clear organelle membranes and proteins such as ribosomes. With

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912-503: A species of geometer moth ("tissue") found in Afro-Eurasia Paper products [ edit ] Tissue paper , a type of thin, gauzy translucent paper used for wrapping and cushioning items Tissue (cloth) , a thin, transparent, and lightweight fabric Facial tissue , tissue paper used for cleaning the face Japanese tissue , tissue paper from Japan made of vegetable fibers Toilet paper , tissue paper used for cleaning

988-535: A supporting tissue in stems of young plants. It provides mechanical support, elasticity, and tensile strength to the plant body. It helps in manufacturing sugar and storing it as starch. It is present in the margin of leaves and resists tearing effect of the wind. Sclerenchyma (Greek, Sclerous means hard and enchyma means infusion) consists of thick-walled, dead cells and protoplasm is negligible. These cells have hard and extremely thick secondary walls due to uniform distribution and high secretion of lignin and have

1064-536: A thin and elastic primary cell wall made of cellulose . They are compactly arranged without inter-cellular spaces between them. Each cell contains a dense cytoplasm and a prominent cell nucleus . The dense protoplasm of meristematic cells contains very few vacuoles . Normally the meristematic cells are oval, polygonal , or rectangular in shape. Meristematic tissue cells have a large nucleus with small or no vacuoles because they have no need to store anything, as opposed to their function of multiplying and increasing

1140-437: A very small glass ball lens between the holes in two metal plates riveted together, and with an adjustable-by-screws needle attached to mount the specimen. Then, Van Leeuwenhoek re-discovered red blood cells (after Jan Swammerdam ) and spermatozoa , and helped popularise the use of microscopes to view biological ultrastructure. On 9 October 1676, van Leeuwenhoek reported the discovery of micro-organisms. The performance of

1216-594: A wide range of stretch lengths. It is found in such organs as sea anemone tentacles and the body wall of sea cucumbers . Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found in earthworms that can extend slowly or make rapid contractions. In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle

1292-427: Is a laboratory instrument used to examine objects that are too small to be seen by the naked eye . Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisible to the eye unless aided by a microscope. There are many types of microscopes, and they may be grouped in different ways. One way is to describe the method an instrument uses to interact with

1368-538: Is a central element in human anatomy , and he considered organs as collections of often disparate tissues, rather than as entities in themselves". Although he worked without a microscope , Bichat distinguished 21 types of elementary tissues from which the organs of the human body are composed, a number later reduced by other authors. Microscope A microscope (from Ancient Greek μικρός ( mikrós )  'small' and σκοπέω ( skopéō )  'to look (at); examine, inspect')

1444-466: Is a living tissue of primary body like Parenchyma . Cells are thin-walled but possess thickening of cellulose , water and pectin substances ( pectocellulose ) at the corners where a number of cells join. This tissue gives tensile strength to the plant and the cells are compactly arranged and have very little inter-cellular spaces. It occurs chiefly in hypodermis of stems and leaves. It is absent in monocots and in roots. Collenchymatous tissue acts as

1520-405: Is also known as conducting and vascular tissue. The common types of complex permanent tissue are: Xylem and phloem together form vascular bundles. Xylem (Greek, xylos = wood) serves as a chief conducting tissue of vascular plants. It is responsible for the conduction of water and inorganic solutes. Xylem consists of four kinds of cells: Xylem tissue is organised in a tube-like fashion along

1596-696: Is an equally important plant tissue as it also is part of the 'plumbing system' of a plant. Primarily, phloem carries dissolved food substances throughout the plant. This conduction system is composed of sieve-tube member and companion cells, that are without secondary walls. The parent cells of the vascular cambium produce both xylem and phloem. This usually also includes fibers, parenchyma and ray cells. Sieve tubes are formed from sieve-tube members laid end to end. The end walls, unlike vessel members in xylem, do not have openings. The end walls, however, are full of small pores where cytoplasm extends from cell to cell. These porous connections are called sieve plates. In spite of

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1672-456: Is based on the use of non-reflecting substrates for cross-polarized reflected light microscopy. Ultraviolet light enables the resolution of microscopic features as well as the imaging of samples that are transparent to the eye. Near infrared light can be used to visualize circuitry embedded in bonded silicon devices, since silicon is transparent in this region of wavelengths. In fluorescence microscopy many wavelengths of light ranging from

1748-402: Is based on what interacts with the sample to generate the image, i.e., light or photons (optical microscopes), electrons (electron microscopes) or a probe (scanning probe microscopes). Alternatively, microscopes can be classified based on whether they analyze the sample via a scanning point (confocal optical microscopes, scanning electron microscopes and scanning probe microscopes) or analyze

1824-508: Is called an extracellular matrix . This matrix can be liquid or rigid. For example, blood contains plasma as its matrix and bone's matrix is rigid. Connective tissue gives shape to organs and holds them in place. Blood, bone, tendon, ligament, adipose, and areolar tissues are examples of connective tissues. One method of classifying connective tissues is to divide them into three types: fibrous connective tissue, skeletal connective tissue, and fluid connective tissue. Muscle cells (myocytes) form

1900-411: Is found in the walls of the uterus , bladder , intestines , stomach , oesophagus , respiratory airways , and blood vessels . Cardiac muscle is found only in the heart , allowing it to contract and pump blood through the body. Cells comprising the central nervous system and peripheral nervous system are classified as nervous (or neural) tissue. In the central nervous system, neural tissues form

1976-422: Is illuminated with infrared photons, each of which is spatially correlated with an entangled partner in the visible band for efficient imaging by a photon-counting camera. The two major types of electron microscopes are transmission electron microscopes (TEMs) and scanning electron microscopes (SEMs). They both have series of electromagnetic and electrostatic lenses to focus a high energy beam of electrons on

2052-411: Is limited by the wavelength of the radiation used to image the sample, where shorter wavelengths allow for a higher resolution. Scanning optical and electron microscopes, like the confocal microscope and scanning electron microscope, use lenses to focus a spot of light or electrons onto the sample then analyze the signals generated by the beam interacting with the sample. The point is then scanned over

2128-520: Is present. Cells of this type of tissue are roughly spherical or polyhedral to rectangular in shape, with thin cell walls . New cells produced by meristem are initially those of meristem itself, but as the new cells grow and mature, their characteristics slowly change and they become differentiated as components of meristematic tissue, being classified as: There are two types of meristematic Tissue 1.Primary meristem. 2.Secondary meristem. The cells of meristematic tissue are similar in structure and have

2204-477: Is somewhat variable. Most classification schemes combine a description of the cell-shape in the upper layer of the epithelium with a word denoting the number of layers: either simple (one layer of cells) or stratified (multiple layers of cells). However, other cellular features such as cilia may also be described in the classification system. Some common kinds of epithelium are listed below: Connective tissues are made up of cells separated by non-living material, which

2280-486: The Accademia dei Lincei in 1625 (Galileo had called it the occhiolino 'little eye'). René Descartes ( Dioptrique , 1637) describes microscopes wherein a concave mirror, with its concavity towards the object, is used, in conjunction with a lens, for illuminating the object, which is mounted on a point fixing it at the focus of the mirror. The first detailed account of the microscopic anatomy of organic tissue based on

2356-465: The histological stain , and the optical microscope . Developments in electron microscopy , immunofluorescence , and the use of frozen tissue-sections have enhanced the detail that can be observed in tissues. With these tools, the classical appearances of tissues can be examined in health and disease , enabling considerable refinement of medical diagnosis and prognosis . In plant anatomy , tissues are categorized broadly into three tissue systems:

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2432-545: The Second World War . Ernst Ruska, working at Siemens , developed the first commercial transmission electron microscope and, in the 1950s, major scientific conferences on electron microscopy started being held. In 1965, the first commercial scanning electron microscope was developed by Professor Sir Charles Oatley and his postgraduate student Gary Stewart, and marketed by the Cambridge Instrument Company as

2508-512: The atomic force microscope , then Binnig's and Rohrer's Nobel Prize in Physics for the SPM. New types of scanning probe microscope have continued to be developed as the ability to machine ultra-fine probes and tips has advanced. The most recent developments in light microscope largely centre on the rise of fluorescence microscopy in biology . During the last decades of the 20th century, particularly in

2584-431: The brain and spinal cord . In the peripheral nervous system, neural tissues form the cranial nerves and spinal nerves , inclusive of the motor neurons . Mineralized tissues are biological tissues that incorporate minerals into soft matrices. Such tissues may be found in both plants and animals. Xavier Bichat introduced the word tissue into the study of anatomy by 1801. He was "the first to propose that tissue

2660-463: The ectoderm and endoderm (or their precursor in sponges ), with a small contribution from the mesoderm , forming the endothelium , a specialized type of epithelium that composes the vasculature . By contrast, a true epithelial tissue is present only in a single layer of cells held together via occluding junctions called tight junctions , to create a selectively permeable barrier. This tissue covers all organismal surfaces that come in contact with

2736-406: The epidermis , the ground tissue , and the vascular tissue . Plant tissues can also be divided differently into two types: Meristematic tissue consists of actively dividing cells and leads to increase in length and thickness of the plant. The primary growth of a plant occurs only in certain specific regions, such as in the tips of stems or roots. It is in these regions that meristematic tissue

2812-419: The quantum tunnelling phenomenon. They created a practical instrument, a scanning probe microscope from quantum tunnelling theory, that read very small forces exchanged between a probe and the surface of a sample. The probe approaches the surface so closely that electrons can flow continuously between probe and sample, making a current from surface to probe. The microscope was not initially well received due to

2888-501: The "Stereoscan". One of the latest discoveries made about using an electron microscope is the ability to identify a virus. Since this microscope produces a visible, clear image of small organelles, in an electron microscope there is no need for reagents to see the virus or harmful cells, resulting in a more efficient way to detect pathogens. From 1981 to 1983 Gerd Binnig and Heinrich Rohrer worked at IBM in Zürich , Switzerland to study

2964-476: The French word " tissu ", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology . Xavier Bichat is considered as the "Father of Histology". Plant histology is studied in both plant anatomy and physiology . The classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned,

3040-420: The active contractile tissue of the body. Muscle tissue functions to produce force and cause motion, either locomotion or movement within internal organs. Muscle is formed of contractile filaments and is separated into three main types; smooth muscle , skeletal muscle and cardiac muscle . Smooth muscle has no striations when examined microscopically. It contracts slowly but maintains contractibility over

3116-417: The anus Wrapping tissue , tissue paper used for wrapping and cushioning items Other [ edit ] Aerial tissue , an acrobatic art form and one of the circus arts " The Tissue (Tomaranai Seishun) ", a 2011 song by Shiritsu Ebisu Chugaku Tissue , a 2017 poem by Imtiaz Dharker Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

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3192-409: The application. Digital microscopy with very low light levels to avoid damage to vulnerable biological samples is available using sensitive photon-counting digital cameras. It has been demonstrated that a light source providing pairs of entangled photons may minimize the risk of damage to the most light-sensitive samples. In this application of ghost imaging to photon-sparse microscopy, the sample

3268-456: The colourless substance that covers the sieve plate. Callose stays in solution as long as the cell contents are under pressure. Phloem transports food and materials in plants upwards and downwards as required. Animal tissues are grouped into four basic types: connective , muscle , nervous , and epithelial . Collections of tissues joined in units to serve a common function compose organs. While most animals can generally be considered to contain

3344-460: The complex nature of the underlying theoretical explanations. In 1984 Jerry Tersoff and D.R. Hamann, while at AT&T's Bell Laboratories in Murray Hill, New Jersey began publishing articles that tied theory to the experimental results obtained by the instrument. This was closely followed in 1985 with functioning commercial instruments, and in 1986 with Gerd Binnig, Quate, and Gerber's invention of

3420-425: The current is kept constant by computer movement of the tip and an image is formed by the recorded movements of the tip. Scanning acoustic microscopes use sound waves to measure variations in acoustic impedance. Similar to Sonar in principle, they are used for such jobs as detecting defects in the subsurfaces of materials including those found in integrated circuits. On February 4, 2013, Australian engineers built

3496-526: The diffraction limit is occurred from light or excitation, which makes the resolution must be doubled to become super saturated. Stefan Hell was awarded the 2014 Nobel Prize in Chemistry for the development of the STED technique, along with Eric Betzig and William Moerner who adapted fluorescence microscopy for single-molecule visualization. X-ray microscopes are instruments that use electromagnetic radiation usually in

3572-449: The earliest known use of simple microscopes ( magnifying glasses ) dates back to the widespread use of lenses in eyeglasses in the 13th century. The earliest known examples of compound microscopes, which combine an objective lens near the specimen with an eyepiece to view a real image , appeared in Europe around 1620. The inventor is unknown, even though many claims have been made over

3648-473: The early 20th century a significant alternative to the light microscope was developed, an instrument that uses a beam of electrons rather than light to generate an image. The German physicist, Ernst Ruska , working with electrical engineer Max Knoll , developed the first prototype electron microscope in 1931, a transmission electron microscope (TEM). The transmission electron microscope works on similar principles to an optical microscope but uses electrons in

3724-433: The ends. They do not have end openings such as the vessels. The end overlap with each other, with pairs of pits present. The pit pairs allow water to pass from cell to cell. Though most conduction in xylem tissue is vertical, lateral conduction along the diameter of a stem is facilitated via rays. Rays are horizontal rows of long-living parenchyma cells that arise out of the vascular cambium. Phloem consists of: Phloem

3800-414: The external environment such as the skin , the airways, and the digestive tract. It serves functions of protection, secretion , and absorption, and is separated from other tissues below by a basal lamina . The connective tissue and the muscular are derived from the mesoderm. The nervous tissue is derived from the ectoderm. The epithelial tissues are formed by cells that cover the organ surfaces, such as

3876-451: The eye or on to another light detector. Mirror-based optical microscopes operate in the same manner. Typical magnification of a light microscope, assuming visible range light, is up to 1,250× with a theoretical resolution limit of around 0.250  micrometres or 250  nanometres . This limits practical magnification to ~1,500×. Specialized techniques (e.g., scanning confocal microscopy , Vertico SMI ) may exceed this magnification but

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3952-399: The fact that their cytoplasm is actively involved in the conduction of food materials, sieve-tube members do not have nuclei at maturity. It is the companion cells that are nestled between sieve-tube members that function in some manner bringing about the conduction of food. Sieve-tube members that are alive contain a polymer called callose, a carbohydrate polymer, forming the callus pad/callus,

4028-400: The four tissue types, the manifestation of these tissues can differ depending on the type of organism. For example, the origin of the cells comprising a particular tissue type may differ developmentally for different classifications of animals. Tissue appeared for the first time in the diploblasts , but modern forms only appeared in triploblasts . The epithelium in all animals is derived from

4104-400: The girth and length of the plant, with no intercellular spaces. Permanent tissues may be defined as a group of living or dead cells formed by meristematic tissue and have lost their ability to divide and have permanently placed at fixed positions in the plant body. Meristematic tissues that take up a specific role lose the ability to divide. This process of taking up a permanent shape, size and

4180-416: The light to pass through. The microscope can capture either transmitted or reflected light to measure very localized optical properties of the surface, commonly of a biological specimen. Scanning tunneling microscopes have a metal tip with a single apical atom; the tip is attached to a tube through which a current flows. The tip is scanned over the surface of a conductive sample until a tunneling current flows;

4256-399: The lungs. The publication in 1665 of Robert Hooke 's Micrographia had a huge impact, largely because of its impressive illustrations. Hooke created tiny lenses of small glass globules made by fusing the ends of threads of spun glass. A significant contribution came from Antonie van Leeuwenhoek who achieved up to 300 times magnification using a simple single lens microscope. He sandwiched

4332-471: The main axes of stems and roots. It consists of a combination of parenchyma cells, fibers, vessels, tracheids, and ray cells. Longer tubes made up of individual cellssels tracheids, while vessel members are open at each end. Internally, there may be bars of wall material extending across the open space. These cells are joined end to end to form long tubes. Vessel members and tracheids are dead at maturity. Tracheids have thick secondary cell walls and are tapered at

4408-512: The many different types of interactions that occur when a small probe is scanned over and interacts with a specimen. These interactions or modes can be recorded or mapped as function of location on the surface to form a characterization map. The three most common types of scanning probe microscopes are atomic force microscopes (AFM), near-field scanning optical microscopes (NSOM or SNOM, scanning near-field optical microscopy), and scanning tunneling microscopes (STM). An atomic force microscope has

4484-494: The place of light and electromagnets in the place of glass lenses. Use of electrons, instead of light, allows for much higher resolution. Development of the transmission electron microscope was quickly followed in 1935 by the development of the scanning electron microscope by Max Knoll . Although TEMs were being used for research before WWII, and became popular afterwards, the SEM was not commercially available until 1965. Transmission electron microscopes became popular following

4560-411: The plant consists of a single layer of cells called epidermis or surface tissue. The entire surface of the plant has this outer layer of the epidermis. Hence it is also called surface tissue. Most of the epidermal cells are relatively flat. The outer and lateral walls of the cell are often thicker than the inner walls. The cells form a continuous sheet without intercellular spaces. It protects all parts of

4636-464: The plant. The outer epidermis is coated with a waxy thick layer called cutin which prevents loss of water. The epidermis also consists of stomata (singular:stoma) which helps in transpiration . The complex permanent tissue consists of more than one type of cells having a common origin which work together as a unit. Complex tissues are mainly concerned with the transportation of mineral nutrients, organic solutes (food materials), and water. That's why it

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4712-491: The post- genomic era, many techniques for fluorescent staining of cellular structures were developed. The main groups of techniques involve targeted chemical staining of particular cell structures, for example, the chemical compound DAPI to label DNA , use of antibodies conjugated to fluorescent reporters, see immunofluorescence , and fluorescent proteins, such as green fluorescent protein . These techniques use these different fluorophores for analysis of cell structure at

4788-518: The resolution is diffraction limited. The use of shorter wavelengths of light, such as ultraviolet, is one way to improve the spatial resolution of the optical microscope, as are devices such as the near-field scanning optical microscope . Sarfus is a recent optical technique that increases the sensitivity of a standard optical microscope to a point where it is possible to directly visualize nanometric films (down to 0.3 nanometre) and isolated nano-objects (down to 2 nm-diameter). The technique

4864-404: The same resolution limit as the optical and electron microscopes described above. The most common type of microscope (and the first invented) is the optical microscope . This is an optical instrument containing one or more lenses producing an enlarged image of a sample placed in the focal plane. Optical microscopes have refractive glass (occasionally plastic or quartz ), to focus light on

4940-554: The sample all at once (wide field optical microscopes and transmission electron microscopes). Wide field optical microscopes and transmission electron microscopes both use the theory of lenses ( optics for light microscopes and electromagnet lenses for electron microscopes) in order to magnify the image generated by the passage of a wave transmitted through the sample, or reflected by the sample. The waves used are electromagnetic (in optical microscopes ) or electron beams (in electron microscopes ). Resolution in these microscopes

5016-541: The sample to analyze a rectangular region. Magnification of the image is achieved by displaying the data from scanning a physically small sample area on a relatively large screen. These microscopes have the same resolution limit as wide field optical, probe, and electron microscopes. Scanning probe microscopes also analyze a single point in the sample and then scan the probe over a rectangular sample region to build up an image. As these microscopes do not use electromagnetic or electron radiation for imaging they are not subject to

5092-495: The slide. This microscope technique made it possible to study the cell cycle in live cells. The traditional optical microscope has more recently evolved into the digital microscope . In addition to, or instead of, directly viewing the object through the eyepieces , a type of sensor similar to those used in a digital camera is used to obtain an image, which is then displayed on a computer monitor. These sensors may use CMOS or charge-coupled device (CCD) technology, depending on

5168-560: The soft X-ray band to image objects. Technological advances in X-ray lens optics in the early 1970s made the instrument a viable imaging choice. They are often used in tomography (see micro-computed tomography ) to produce three dimensional images of objects, including biological materials that have not been chemically fixed. Currently research is being done to improve optics for hard X-rays which have greater penetrating power. Microscopes can be separated into several different classes. One grouping

5244-639: The surface of skin , the airways , surfaces of soft organs, the reproductive tract , and the inner lining of the digestive tract . The cells comprising an epithelial layer are linked via semi-permeable, tight junctions ; hence, this tissue provides a barrier between the external environment and the organ it covers. In addition to this protective function, epithelial tissue may also be specialized to function in secretion , excretion and absorption . Epithelial tissue helps to protect organs from microorganisms, injury, and fluid loss. Functions of epithelial tissue: There are many kinds of epithelium, and nomenclature

5320-458: The technique rapidly gained popularity through the 1980s. Much current research (in the early 21st century) on optical microscope techniques is focused on development of superresolution analysis of fluorescently labelled samples. Structured illumination can improve resolution by around two to four times and techniques like stimulated emission depletion (STED) microscopy are approaching the resolution of electron microscopes. This occurs because

5396-609: The title Tissue . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Tissue&oldid=1227218173 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Tissue (biology) Biological organisms follow this hierarchy : Cells < Tissue < Organ < Organ System < Organism The English word "tissue" derives from

5472-435: The ultraviolet to the visible can be used to cause samples to fluoresce , which allows viewing by eye or with specifically sensitive cameras. Phase-contrast microscopy is an optical microscopic illumination technique in which small phase shifts in the light passing through a transparent specimen are converted into amplitude or contrast changes in the image. The use of phase contrast does not require staining to view

5548-599: The use of a microscope did not appear until 1644, in Giambattista Odierna's L'occhio della mosca , or The Fly's Eye . The microscope was still largely a novelty until the 1660s and 1670s when naturalists in Italy, the Netherlands and England began using them to study biology. Italian scientist Marcello Malpighi , called the father of histology by some historians of biology, began his analysis of biological structures with

5624-654: The vacuole is of much smaller size than of normal animal cells. This tissue provides support to plants and also stores food. Chlorenchyma is a special type of parenchyma that contains chlorophyll and performs photosynthesis. In aquatic plants, aerenchyma tissues, or large air cavities, give support to float on water by making them buoyant. Parenchyma cells called idioblasts have metabolic waste. Spindle shaped fibers are also present in this cell to support them and known as prosenchyma, succulent parenchyma also noted. In xerophytes , parenchyma tissues store water. Collenchyma (Greek, 'Colla' means gum and 'enchyma' means infusion)

5700-482: The years. Several revolve around the spectacle-making centers in the Netherlands , including claims it was invented in 1590 by Zacharias Janssen (claim made by his son) or Zacharias' father, Hans Martens, or both, claims it was invented by their neighbor and rival spectacle maker, Hans Lippershey (who applied for the first telescope patent in 1608), and claims it was invented by expatriate Cornelis Drebbel , who

5776-524: Was noted to have a version in London in 1619. Galileo Galilei (also sometimes cited as compound microscope inventor) seems to have found after 1610 that he could close focus his telescope to view small objects and, after seeing a compound microscope built by Drebbel exhibited in Rome in 1624, built his own improved version. Giovanni Faber coined the name microscope for the compound microscope Galileo submitted to

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