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Fibrinoid Degeneration
Fibrinoid necrosis is a pathological lesion that affects blood vessels, and is characterized by the occurrence of endothelial damage, followed by leakage of plasma proteins, including fibrinogen, from the vessel lumen; these proteins infiltrate and deposit within the vessel walls, where fibrin polymerization subsequently ensues. Although the term ''fibrinoid'' essentially means "fibrin-like", it has been confirmed through immunohistochemical analysis and electron microscopy that the areas referred to as "fibrin-like" do contain fibrin, whose predominant presence contributes to the bright, eosinophilic (pinkish) and structureless appearance of the affected vessels. The earliest documented identification of fibrinoid changes dates back to 1880, when it was questioned whether these histological changes resulted from the deposition of a fibrinous exudate, or the degeneration and breakdown of collagen fibers. The term ''fibrinoid'' was introduced to describe these changes, because dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Vessel
Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (biology), body. They also take waste and carbon dioxide away from the tissues. Some tissues such as cartilage, epithelium, and the lens (anatomy), lens and cornea of the eye are not supplied with blood vessels and are termed ''avascular''. There are five types of blood vessels: the arteries, which carry the blood away from the heart; the arterioles; the capillaries, where the exchange of water and chemicals between the blood and the tissues occurs; the venules; and the veins, which carry blood from the capillaries back towards the heart. The word ''vascular'', is derived from the Latin ''vas'', meaning ''vessel'', and is mostly used in relation to blood vessels. Etymology * artery – late Middle English; from Latin ''arteria'', from Gree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laboratory Rat
Laboratory rats or lab rats are strain (biology), strains of the rat subspecies ''Rattus norvegicus domestica'' (Domestic Norwegian rat) which are bred and kept for scientific research. While Animal testing on rodents, less commonly used for research than laboratory mice, rats have served as an important animal model for research in psychology and biomedical science, and "lab rat" is commonly used as an idiom for a test subject. Origins of rat breeding In 18th-century Europe, wild brown rats (''Rattus norvegicus'') ran rampant and this infestation fueled the industry of rat-catching. Rat-catchers would not only make money by trapping the rodents, but also by selling them rat meat, for food or, more commonly, for rat-baiting. Rat-baiting was a popular sport, which involved filling a pit with rats and timing how long it took for a terrier to kill them all. Over time, breeding the rats for these contests may have produced color variations, notably the albino rat, albino and hoode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arteriole
An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillary, capillaries. Arterioles have vascular smooth muscle, muscular walls (usually only one to two layers of smooth muscle cells) and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries. This function is extremely important because it prevents the thin, one-layer capillaries from exploding upon pressure. The arterioles achieve this decrease in pressure, as they are the site with the highest resistance (a large contributor to total peripheral resistance) which translates to a large decrease in the pressure. Structure In a healthy vascular system, the endothelium lines all blood-contacting surfaces, including arteries, arterioles, veins, venules, capillaries, and heart chambers. This healthy condition is promoted by the ample production of n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arteriolosclerosis
Arteriolosclerosis is a form of cardiovascular disease involving hardening and loss of elasticity of arterioles or small arteries and is most often associated with hypertension and diabetes mellitus. Types include hyaline arteriolosclerosis and hyperplastic arteriolosclerosis, both involved with vessel wall thickening and luminal narrowing that may cause downstream ischemic injury. The following two terms whilst similar, are distinct in both spelling and meaning and may easily be confused with arteriolosclerosis. * Arteriosclerosis is any hardening (and loss of elasticity) of medium or large arteries (from the Greek '' arteria'', meaning ''artery'', and '' sclerosis'', meaning ''hardening'') * Atherosclerosis is a hardening of an artery specifically due to an atheromatous plaque. The term ''atherogenic'' is used for substances or processes that cause atherosclerosis. Hyaline arteriolosclerosis Also arterial hyalinosis and arteriolar hyalinosis refers to thickening of the wal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Textbook
A textbook is a book containing a comprehensive compilation of content in a branch of study with the intention of explaining it. Textbooks are produced to meet the needs of educators, usually at educational institutions, but also of learners (who could be independent learners outside of formal education). Schoolbooks are textbooks and other books used in schools. Today, many textbooks are published in both print and digital formats. History The history of textbooks dates back to ancient civilizations. For example, Ancient Greeks wrote educational texts. The modern textbook has its roots in the mass production made possible by the printing press. Johannes Gutenberg himself may have printed editions of ''Ars Minor'', a schoolbook on Latin grammar by Aelius Donatus. Early textbooks were used by tutors and teachers (e.g. alphabet books), as well as by individuals who taught themselves. The Greek philosopher Socrates lamented the loss of knowledge because the media of transmis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesentery
In human anatomy, the mesentery is an Organ (anatomy), organ that attaches the intestines to the posterior abdominal wall, consisting of a double fold of the peritoneum. It helps (among other functions) in storing Adipose tissue, fat and allowing blood vessels, lymphatics, and nerves to supply the intestines. The (the part of the mesentery that attaches the colon to the abdominal wall) was formerly thought to be a fragmented structure, with all named parts—the ascending, transverse, descending, and sigmoid mesocolons, the mesoappendix, and the mesorectum—separately terminating their insertion into the posterior abdominal wall. However, in 2012, new microscopy, microscopic and electron microscope, electron microscopic histology, examinations showed the mesocolon to be a single structure derived from the duodenojejunal flexure and extending to the distal mesorectal layer. Thus the mesentery is an internal organ. Structure The mesentery of the small intestine arises from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kidney
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal artery, renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the urinary bladder, bladder. The kidney participates in the control of the volume of various body fluids, fluid osmolality, Acid-base homeostasis, acid-base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus (kidney), glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertensive Emergency
A hypertensive emergency is very high blood pressure with potentially life-threatening symptoms and signs of acute damage to one or more organ systems (especially brain, eyes, heart, aorta, or kidneys). It is different from a hypertensive urgency by this additional evidence for impending irreversible hypertension-mediated organ damage (HMOD). Blood pressure is often above 200/120 mmHg, however there are no universally accepted cutoff values. Signs and symptoms Symptoms may include headache, nausea, or vomiting. Chest pain may occur due to increased workload on the heart resulting in inadequate delivery of oxygen to meet the heart muscle's metabolic needs. The kidneys may be affected, resulting in blood or protein in the urine, and acute kidney failure. People can have decreased urine production, fluid retention, and confusion. Other signs and symptoms can include: * Chest pain * Abnormal heart rhythms * Headache * Nosebleeds that are difficult to stop * Dyspnea * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Circulation
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products. The neurovascular unit regulates cerebral blood flow so that activated neurons can be supplied with energy in the right amount and at the right time. Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids are broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/ unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipohyalinosis
Lipohyalinosis is a cerebral small vessel disease affecting the small arteries, arterioles or capillaries in the brain. Originally defined by C. Miller Fisher as 'segmental arteriolar wall disorganisation', it is characterized by vessel wall thickening and a resultant reduction in luminal diameter. Fisher considered this small vessel disease to be the result of hypertension, induced in the acute stage by fibrinoid necrosis that would lead to occlusion and hence lacunar stroke. However, recent evidence suggests that endothelial dysfunction as a result of inflammation is a more likely cause for it. This may occur subsequent to blood–brain barrier failure, and lead to extravasation of serum components into the brain that are potentially toxic. Lacunar infarction could thus occur in this way, and the narrowing – the hallmark feature of lipohyalinosis – may merely be a feature of the swelling occurring around it that squeezes on the structure. Misuse of the term C. Miller Fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscope
A microscope () is a laboratory equipment, 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 a sample and produce images, either by sending a beam of light or electrons through a sample in its optical path, by detecting fluorescence, 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 a microtome, thinly sectioned sample to produce an observable image. Other major types of microscopes are the fluorescence micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
