A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image, taken on a microscope but is only magnified less than 10 times. Micrography is the art of using microscopes to make photographs. A micrograph contains extensive details of microstructure. A wealth of information can be obtained from a simple micrograph like behavior of the material under different conditions, the phases found in the system, failure analysis, grain size estimation, elemental analysis and so on. Micrographs are used in all fields of microscopy. A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, a process referred to as photomicroscopy. At a basic level, photomicroscopy may be performed by connecting a camera to a microscope, thereby enabling the user to take photographs at reasonably high magnification. Scientific use began in England in 1850 by Prof Richard Hill Norris FRSE for his studies of blood cells.
Roman Vishniac was a pioneer in the field of photomicroscopy, specializing in the photography of living creatures in full motion. He made major developments in light-interruption photography and color photomicroscopy. Photomicrographs may be obtained using a USB microscope attached directly to a home computer or laptop. An electron micrograph is a micrograph prepared using an electron microscope. Micrographs have micron bars, or magnification ratios, or both. Magnification is a ratio between the size of an object on its real size. Magnification can be a misleading parameter as it depends on the final size of a printed picture and therefore varies with picture size. A scale bar, or micron bar, is a line of known length displayed on a picture; the bar can be used for measurements on a picture. When the picture is resized the bar is resized making it possible to recalculate the magnification. Ideally, all pictures destined for publication/presentation should be supplied with a scale bar. All but one of the micrographs presented on this page do not have a micron bar.
The microscope has been used for scientific discovery. It has been linked to the arts since its invention in the 17th century. Early adopters of the microscope, such as Robert Hooke and Antonie van Leeuwenhoek, were excellent illustrators. After the invention of photography in the 1820s the microscope was combined with the camera to take pictures instead of relying on an artistic rendering. Since the early 1970s individuals have been using the microscope as an artistic instrument. Websites and traveling art exhibits such as the Nikon Small World and Olympus Bioscapes have featured a range of images for the sole purpose of artistic enjoyment; some collaborative groups, such as the Paper Project have incorporated microscopic imagery into tactile art pieces as well as 3D immersive rooms and dance performances. Close-up Digital microscope Macro photography Microphotograph Microscopy USB microscope Make a Micrograph – This presentation by the research department of Children's Hospital Boston shows how researchers create a three-color micrograph.
Shots with a Microscope – a basic, comprehensive guide to photomicrography Scientific photomicrographs – free scientific quality photomicrographs by Doc. RNDr. Josef Reischig, CSc. Micrographs of 18 natural fibres by the International Year of Natural Fibres 2009 Seeing Beyond the Human Eye Video produced by Off Book - Solomon C. Fuller bio Charles Krebs Microscopic Images Dennis Kunkel Microscopy Andrew Paul Leonard, APL Microscopic Cell Centered Database - Montage Nikon Small World Olympus Bioscapes Other examples
Gastrin is a peptide hormone that stimulates secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach and the pancreas. Gastrin binds to cholecystokinin B receptors to stimulate the release of histamines in enterochromaffin-like cells, it induces the insertion of K+/H+ ATPase pumps into the apical membrane of parietal cells, its release is stimulated by peptides in the lumen of the stomach. In humans, the GAS gene is located on the long arm of the seventeenth chromosome. Gastrin is a linear peptide hormone produced by G cells of the duodenum and in the pyloric antrum of the stomach, it is secreted into the bloodstream. The encoded polypeptide is preprogastrin, cleaved by enzymes in posttranslational modification to produce progastrin and gastrin in various forms the following three: gastrin-34 gastrin-17 gastrin-14 Also, pentagastrin is an artificially synthesized, five amino acid sequence identical to the last five amino acid sequence at the C-terminus end of gastrin.
The numbers refer to the amino acid count. Gastrin is released in response to certain stimuli; these include: stomach antrum distension vagal stimulation the presence of digested proteins amino acids, in the stomach. Aromatic amino acids are powerful stimuli for gastrin release. Hypercalcemia Gastrin release is inhibited by: the presence of acid in the stomach somatostatin inhibits the release of gastrin, along with secretin, GIP, VIP, glucagon and calcitonin; the presence of gastrin stimulates parietal cells of the stomach to secrete hydrochloric acid /gastric acid. This is done both directly on the parietal cell and indirectly via binding onto CCK2/gastrin receptors on ECL cells in the stomach, which responds by releasing histamine, which in turn acts in a paracrine manner on parietal cells stimulating them to secrete H+ ions; this is the major stimulus for acid secretion by parietal cells. Along with the above-mentioned function, gastrin has been shown to have additional functions as well: Stimulates parietal cell maturation and fundal growth.
Causes chief cells to secrete pepsinogen, the zymogen form of the digestive enzyme pepsin. Increases promotes stomach contractions. Strengthens antral contractions against the pylorus, relaxes the pyloric sphincter, which increases the rate of gastric emptying. Plays a role in the relaxation of the ileocecal valve. Induces pancreatic secretions and gallbladder emptying. May impact lower esophageal sphincter tone, causing it to contract, - although pentagastrin, rather than endogenous gastrin, may be the cause. Gastrin contributes to the gastrocolic reflex. Factors influencing secretion of gastrin can be divided into 2 categories: Stimulatory factors: dietary protein and amino acids, hypercalcemia. Inhibitory factor: acidity - a negative feedback mechanism, exerted via the release of somatostatin from δ cells in the stomach, which inhibits gastrin and histamine release. Stimulatory factor: bombesin or gastrin-releasing peptide Inhibitory factor: somatostatin - acts on somatostatin-2 receptors on G cells.
In a paracrine manner via local diffusion in the intercellular spaces, but systemically through its release into the local mucosal blood circulation. Stimulatory factors: Beta-adrenergic agents, cholinergic agents, gastrin-releasing peptide Inhibitory factor: Enterogastric reflex Stimulatory factor: epinephrine Inhibitory factors:gastric inhibitory peptide, somatostatin, calcitonin Gastrinoma paraneoplastic oversecretion In the Zollinger–Ellison syndrome, gastrin is produced at excessive levels by a gastrinoma of the duodenum or the pancreas. To investigate for hypergastrinemia, a "pentagastrin test" can be performed. In autoimmune gastritis, the immune system attacks the parietal cells leading to hypochlorhydria; this results in an elevated gastrin level in an attempt to compensate for increased pH in the stomach. All the parietal cells are lost and achlorhydria results leading to a loss of negative feedback on gastrin secretion. Plasma gastrin concentration is elevated in all individuals with mucolipidosis type IV secondary to a constitutive achlorhydria.
This finding facilitates the diagnosis of patients with this neurogenetic disorder. Additionally, elevated gastrin levels may be present in chronic gastritis resulting from H pylori infection, its existence was first suggested in 1905 by the British physiologist John Sydney Edkins, gastrins were isolated in 1964 by Hilda J. Tracy and Roderic Alfred Gregory at the University of Liverpool. In 1964 the structure of gastrin was determined. Overview at colostate.edu Essentials of Human Physiology by Thomas M. Nosek. Section 6/6ch4/s6ch4_14
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous and cuboidal; these can be arranged in a single layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified, either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei; this sort of tissue is called pseudostratified. All glands are made up of epithelial cells. Functions of epithelial cells include secretion, selective absorption, transcellular transport, sensing. Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane.
Cell junctions are well employed in epithelial tissues. In general, epithelial tissues are classified by the number of their layers and by the shape and function of the cells; the three principal shapes associated with epithelial cells are—squamous and columnar. Squamous epithelium has cells; this is found as the lining of the mouth, the blood vessels and in the alveoli of the lungs. Cuboidal epithelium has cells whose height and width are the same. Columnar epithelium has cells taller. By layer, epithelium is classed as either simple epithelium, only one cell thick or stratified epithelium having two or more cells in thickness or multi-layered – as stratified squamous epithelium, stratified cuboidal epithelium, stratified columnar epithelium, both types of layering can be made up of any of the cell shapes. However, when taller simple columnar epithelial cells are viewed in cross section showing several nuclei appearing at different heights, they can be confused with stratified epithelia; this kind of epithelium is therefore described as pseudostratified columnar epithelium.
Transitional epithelium has cells that can change from squamous to cuboidal, depending on the amount of tension on the epithelium. Simple epithelium is a single layer of cells with every cell in direct contact with the basement membrane that separates it from the underlying connective tissue. In general, it is found where filtration occur; the thinness of the epithelial barrier facilitates these processes. In general, simple epithelial tissues are classified by the shape of their cells; the four major classes of simple epithelium are: simple squamous. Simple squamous. Simple cuboidal: these cells may have secretory, absorptive, or excretory functions. Examples include small collecting ducts of kidney and salivary gland. Simple columnar. Non-ciliated epithelium can possess microvilli; some tissues are referred to as simple glandular columnar epithelium. These secrete mucus and are found in stomach and rectum. Pseudostratified columnar epithelium; the ciliated type is called respiratory epithelium as it is exclusively confined to the larger respiratory airways of the nasal cavity and bronchi.
Stratified epithelium differs from simple epithelium. It is therefore found where body linings have to withstand mechanical or chemical insult such that layers can be abraded and lost without exposing subepithelial layers. Cells flatten as the layers become more apical, though in their most basal layers the cells can be squamous, cuboidal or columnar. Stratified epithelia can have the following specializations: The basic cell types are squamous and columnar classed by their shape. Cells of epithelial tissue are scutoid shaped packed and form a continuous sheet, they have no intercellular spaces. All epithelia is separated from underlying tissues by an extracellular fibrous basement membrane; the lining of the mouth, lung alveoli and kidney tubules are all made of epithelial tissue. The lining of the blood and lymphatic vessels are of a specialised form of epithelium called endothelium. Epithelium lines both the outside and the inside cavities and lumina of bodies; the outermost layer of human skin is composed of dead stratified squamous, keratinized epithelial cells.
Tissues that line the inside of the mouth, the esophagus, the vagina, part of the rectum are composed of nonkeratinized stratified squamous epithelium. Other surfaces that separate body cavities from the outside environment are lined by simple squamous, columnar, or pseudostratified epithelial cells. Other epithelial cells line the insides of the lungs, the gastrointestinal tract, the reproductive and urinary tracts, make up the exocrine and endocrine glands; the outer surface of the cornea is covered with fast-growing regenerated epithelial cells. A specialised form of epithelium – endothelium forms the inner lining of blood vessels and the heart, is known as vascular endotheliu
A gland is a group of cells in an animal's body that synthesizes substances for release into the bloodstream or into cavities inside the body or its outer surface. Every gland is formed by an ingrowth from an epithelial surface; this ingrowth may in the beginning possess a tubular structure, but in other instances glands may start as a solid column of cells which subsequently becomes tubulated. As growth proceeds, the column of cells may split or give off offshoots, in which case a compound gland is formed. In many glands, the number of branches is limited, in others a large structure is formed by repeated growth and sub-division; as a rule, the branches do not unite with one another, but in one instance, the liver, this does occur when a reticulated compound gland is produced. In compound glands the more typical or secretory epithelium is found forming the terminal portion of each branch, the uniting portions form ducts and are lined with a less modified type of epithelial cell. Glands are classified according to their shape.
If the gland retains its shape as a tube throughout it is termed a tubular gland. In the second main variety of gland the secretory portion is enlarged and the lumen variously increased in size; these are termed saccular glands. Glands are divided based on their function into two groups: Endocrine glands secrete substances that circulate through the blood stream; the glands secrete their products through basal lamina into the blood stream. Basil lamina can be seen as a layer around the glands to which a million, maybe more, tiny blood vessels are attached; these glands secrete hormones which play an important role in maintaining homeostasis. The pineal gland, thymus gland, pituitary gland, thyroid gland, the two adrenal glands are all endocrine glands. Exocrine glands secrete their products through a duct onto an outer or inner surface of the body, such as the skin or the gastrointestinal tract. Secretion is directly onto the apical surface; the glands in this group can be divided into three groups: Apocrine glands - a portion of the secreting cell's body is lost during secretion.'Apocrine glands' is used to refer to the apocrine sweat glands, however it is thought that apocrine sweat glands may not be true apocrine glands as they may not use the apocrine method of secretion, e.g. mammary gland, sweat gland of arm pit, pubic region, skin around anus and nipples.
Holocrine glands - the entire cell disintegrates to secrete its substances, e.g. sebaceous glands: meibomian and zeis glands. Merocrine glands - cells secrete their substances by exocytosis, e.g. mucous and serous glands. The type of secretory product of exocrine glands may be one of three categories: Serous glands secrete a watery protein-rich, fluid-like product, e.g. sweat glands. Mucous glands secrete a viscous product, rich in carbohydrates, e.g. goblet cells. Sebaceous glands secrete a lipid product; these glands are known as oil glands, e.g. Fordyce spots and meibomian glands. Adenosis is any disease of a gland; the diseased gland has abnormal formation or development of glandular tissue, sometimes tumorous
General surgery is a surgical specialty that focuses on abdominal contents including esophagus, small bowel, liver, gallbladder and bile ducts, the thyroid gland. They deal with diseases involving the skin, soft tissue, peripheral vascular surgery and hernias and perform endoscopic procedures such as gastroscopy and colonoscopy. General surgeons may sub-specialize into one or more of the following disciplines: In many parts of the world including North America and the United Kingdom, the overall responsibility for trauma care falls under the auspices of general surgery; some general surgeons obtain advanced training in this field and specialty certification surgical critical care. General surgeons must be able to deal with any surgical emergency, they are the first port of call to critically ill or gravely injured patients, must perform a variety of procedures to stabilize such patients, such as thoracostomy, cricothyroidotomy, compartment fasciotomies and emergency laparotomy or thoracotomy to stanch bleeding.
They are called upon to staff surgical intensive care units or trauma intensive care units. All general surgeons are trained in emergency surgery. Bleeding, bowel obstructions and organ perforations are the main problems they deal with. Cholecystectomy, the surgical removal of the gallbladder, is one of the most common surgical procedures done worldwide; this is most done electively, but the gallbladder can become acutely inflamed and require an emergency operation. Infections and rupture of the appendix and small bowel obstructions are other common emergencies; this is a new specialty dealing with minimal access techniques using cameras and small instruments inserted through 3 to 15mm incisions. Robotic surgery is now evolving from this concept. Gallbladders and colons can all be removed with this technique. Hernias are able to be repaired laparoscopically. Bariatric surgery can be performed laparoscopically and there a benefits of doing so to reduce wound complications in obese patients. General surgeons that are trained today are expected to be proficient in laparoscopic procedures.
General surgeons treat a wide variety of major and minor colon and rectal diseases including inflammatory bowel diseases, diverticulitis and rectal cancer, gastrointestinal bleeding and hemorrhoids. General surgeons perform a majority of all non-cosmetic breast surgery from lumpectomy to mastectomy pertaining to the evaluation and treatment of breast cancer. General surgeons can perform vascular surgery if they receive special training and certification in vascular surgery. Otherwise, these procedures are performed by vascular surgery specialists. However, general surgeons are capable of treating minor vascular disorders. General surgeons are trained to remove all or part of the thyroid and parathyroid glands in the neck and the adrenal glands just above each kidney in the abdomen. In many communities, they are the only surgeon trained to do this. In communities that have a number of subspecialists, other subspecialty surgeons may assume responsibility for these procedures. Responsible for all aspects of pre-operative and post-operative care of abdominal organ transplant patients.
Transplanted organs include liver, kidney and more small bowel. Surgical oncologist refers to a general surgical oncologist, but thoracic surgical oncologists, gynecologist and so forth can all be considered surgeons who specialize in treating cancer patients; the importance of training surgeons who sub-specialize in cancer surgery lies in evidence, supported by a number of clinical trials, that outcomes in surgical cancer care are positively associated to surgeon volume—i.e. The more cancer cases a surgeon treats, the more proficient he or she becomes, his or her patients experience improved survival rates as a result; this is another controversial point, but it is accepted—even as common sense—that a surgeon who performs a given operation more will achieve superior results when compared with a surgeon who performs the same procedure. This is true of complex cancer resections such as pancreaticoduodenectomy for pancreatic cancer, gastrectomy with extended lymphadenectomy for gastric cancer.
Surgical oncology is a 2 year fellowship following completion of a general surgery residency. Most cardiothoracic surgeons in the U. S. first complete a general surgery residency, followed by a cardiothoracic surgery fellowship. Pediatric surgery is a subspecialty of general surgery. Pediatric surgeons do surgery on patients age lower than 18. Pediatric surgery is 5 -- 7 years of a 2-3 year fellowship. In the 2000s minimally invasive surgery became more prevalent. Considerable enthusiasm has been built around robot-assisted surgery, despite a lack of data suggesting it has significant benefits that justify its cost. In Canada, New Zealand, the United States general surgery is a five to seven year residency and follows completion of medical school, either MD, MBBS, MBChB, or DO degrees. In Australia and New Zealand, a residency leads to eligibility for Fellowship of the Royal Australasian College of Surgeons. In Canada, residency leads to eligibility for certification by and Fellowship of the Royal College of Physicians and Surgeons of Canada, while in the United States, completion of a residency in general surgery leads to eligibility for board certification by the
Hematoxylin and eosin stain or haematoxylin and eosin stain is one of the principal stains in histology. It is the most used stain in medical diagnosis and is the gold standard. A combination of hematoxylin and eosin, it produces blues and reds; the staining method involves application of hemalum, a complex formed from aluminium ions and hematein. Hemalum colors nuclei of cells blue, along with a few other objects, such as keratohyalin granules and calcified material, which turns blue when exposed to alkaline water; the nuclear staining is followed by counterstaining with an aqueous or alcoholic solution of eosin Y, which colors eosinophilic structures in various shades of red and orange. The staining of nuclei by hemalum is ordinarily due to binding of the dye-metal complex to DNA, but nuclear staining can be obtained after extraction of DNA from tissue sections; the mechanism is different from that of nuclear staining by basic dyes such as thionine or toluidine blue. Staining by basic dyes occurs only from solutions that are less acidic than hemalum, it is prevented by prior chemical or enzymatic extraction of nucleic acids.
There is evidence to indicate that co-ordinate bonds, similar to those that hold aluminium and hematein together, bind the hemalum complex to DNA and to carboxy groups of proteins in the nuclear chromatin. The eosinophilic structures are composed of intracellular or extracellular protein; the Lewy bodies and Mallory bodies are examples of eosinophilic structures. Most of the cytoplasm is eosinophilic. Red blood cells are stained intensely red; the structures do not have to be basic to be called basophilic and eosinophilic. Other colors, e.g. yellow and brown, can be present in the sample. Some structures do not stain well. Basal laminae need to be stained by PAS stain or some silver stains, if they have to be well visible. Reticular fibers require silver stain. Hydrophobic structures tend to remain clear. Hematoxylin is a dark blue or violet stain, basic/positive, it binds to basophilic substances. DNA/RNA in the nucleus, RNA in ribosomes in the rough endoplasmic reticulum are both acidic because the phosphate backbones of nucleic acids are negatively charged.
These backbones form salts with basic dyes containing positive charges. Therefore, dyes stain them violet. Eosin is a red or pink stain, acidic and negative, it binds to acidophilic substances such as positively charged amino-acid side chains. Most proteins in the cytoplasm of some cells are basic because they are positively charged due to the arginine and lysine amino-acid residues; these form salts with acid dyes containing negative charges, like eosin. Therefore, eosin stains them pink; this includes cytoplasmic filaments in muscle cells, intracellular membranes, extracellular fibers. So, in optical microscopy, one can observe: Nuclei in blue/purple Basophils in purplish red Cytoplasm in red Muscles in dark red Erythrocytes in cherry red Collagen in pale pink Mitochondria in pale pink Papanicolaou stain, another popular staining technique Cytopathology Acid-fast Baker JR Experiments on the action of mordants. 2. Aluminium-haematein. Quart. J. Microsc. Sci. 103: 493–517. Kiernan JA Histological and Histochemical Methods: Theory and Practice.
4th ed. Bloxham, UK: Scion. Lillie RD, Pizzolato P, Donaldson PT Nuclear stains with soluble metachrome mordant lake dyes; the effect of chemical endgroup blocking reactions and the artificial introduction of acid groups into tissues. Histochemistry 49: 23–35. Llewellyn BD Nuclear staining with alum-hematoxylin. Biotech. Histochem. 84: 159–177. Marshall PN, Horobin RW The mechanism of action of "mordant" des – a study using preformed metal complexes. Histochemie 35: 361–371. Puchtler H, Meloan SN, Waldrop FS Application of current chemical concepts to metal-haematein and -brazilein stains. Histochemistry 85: 353–364. SIGMA-ALDRICH H&E Informational Primer Routine Mayer's Hematoxylin and Eosin Stain Hematoxylin & Eosin Staining Protocol Rosen Lab, Department of Molecular and Cellular Biology, Baylor College of Medicine) Step by step protocol