"Vascular bundle A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in vascular tissue, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will include supporting and protective tissues. The xylem typically lies adaxial with phloem positioned abaxial. In a stem or root this means that the xylem is closer to the centre of the stem or root while the phloem is closer to the exterior. In a leaf, the adaxial surface of the leaf will usually be the upper side,"
"between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart. The word ""vascular"", meaning relating to the blood vessels, is derived from the Latin ""vas"", meaning vessel. A few structures (such as cartilage and the lens of the eye) do not contain blood vessels and are labeled. The arteries and veins have three layers. The middle layer is thicker in the arteries than it is in the veins: Capillaries consist of little more than a layer of endothelium and occasional connective tissue. When blood vessels connect to form a region of"
"Vascularity Vascularity, in bodybuilding, is the condition of having many highly-visible, prominent, and often extensively-ramified superficial veins. The skin appears ""thin"" — sometimes virtually diaphanous — due to an extreme reduction of subcutaneous fat, allowing for maximum muscle definition. Vascularity is enhanced by extremely low body fat (usually below 10%) and low retained water, as well as the muscle engorgement (""pump"") and venous distension accentuated by the vigorous flexing and potentially hazardous Valsalva effect which characterize competitive posing. Genetics and androgenic hormones will affect vascularity, as will ambient temperature. (And although some bodybuilders develop arterial hypertension from performance-enhancing substances and"
"Vascular dementia Vascular dementia, also known as multi-infarct dementia (MID) and vascular cognitive impairment (VCI), is dementia caused by problems in the supply of blood to the brain, typically a series of minor strokes, leading to worsening cognitive decline that occurs step by step. The term refers to a syndrome consisting of a complex interaction of cerebrovascular disease and risk factors that lead to changes in the brain structures due to strokes and lesions, and resulting changes in cognition. The temporal relationship between a stroke and cognitive deficits is needed to make the diagnosis. Differentiating dementia syndromes can be challenging,"
"Cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. Cardiovascular disease includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, heart arrhythmia, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis. The underlying mechanisms vary depending on the disease. Coronary artery disease, stroke, and peripheral artery disease involve atherosclerosis. This may be caused by high blood pressure, smoking, diabetes, lack of exercise, obesity,"
"Board of Vascular Medicine. Angiology Angiology (from Greek , ""angeīon"", ""vessel""; and , ""-logia"") is the medical specialty which studies the diseases of the circulatory system and of the lymphatic system, i.e., arteries, veins and lymphatic vessels, and its diseases. In the UK, this field is more often termed ""angiology"", and in the United States the term vascular medicine is more frequent. The field of vascular medicine (angiology) is the field that deals with preventing, diagnosing and treating vascular and blood vessel related diseases. Arterial diseases include the aorta (aneurysms/dissection) and arteries supplying the legs, hands, kidneys, brain, intestines. It"
"Vinculum (ligament) In anatomy, a vinculum (pl. vincula) is a band of connective tissue, similar to a ligament, that connect a flexor tendon to a phalanx bone. They contain tiny vessels which supply blood to the tendon. In vertebrate anatomy, they are referred to as mesotendons. For example, in the fingers and toes of humans and related vertebrates, vincula are responsible for the direct vascularization of the flexor digitorum superficialis and profundus tendons to the intermediate and distal phalanges in each finger. These vincula are four folds in the synovial membrane that carry blood vessels to the body and insertion"
"Angiology Angiology (from Greek , ""angeīon"", ""vessel""; and , ""-logia"") is the medical specialty which studies the diseases of the circulatory system and of the lymphatic system, i.e., arteries, veins and lymphatic vessels, and its diseases. In the UK, this field is more often termed ""angiology"", and in the United States the term vascular medicine is more frequent. The field of vascular medicine (angiology) is the field that deals with preventing, diagnosing and treating vascular and blood vessel related diseases. Arterial diseases include the aorta (aneurysms/dissection) and arteries supplying the legs, hands, kidneys, brain, intestines. It also covers arterial thrombosis"
"Cerebral vasculitis Cerebral vasculitis or central nervous system vasculitis (sometimes the word angiitis is used instead of ""vasculitis"") is vasculitis (inflammation of the blood vessel wall) involving the brain and occasionally the spinal cord. It affects all of the vessels: very small blood vessels (capillaries), medium-size blood vessels (arterioles and venules), or large blood vessels (arteries and veins). If blood flow in a vessel with vasculitis is reduced or stopped, the parts of the body that receive blood from that vessel begins to die. It may produce a wide range of neurological symptoms, such as headache, skin rashes, feeling very"
"and sometimes-tragic effects of the resultant water-electrolyte imbalances are well documented. Vascularity Vascularity, in bodybuilding, is the condition of having many highly-visible, prominent, and often extensively-ramified superficial veins. The skin appears ""thin"" — sometimes virtually diaphanous — due to an extreme reduction of subcutaneous fat, allowing for maximum muscle definition. Vascularity is enhanced by extremely low body fat (usually below 10%) and low retained water, as well as the muscle engorgement (""pump"") and venous distension accentuated by the vigorous flexing and potentially hazardous Valsalva effect which characterize competitive posing. Genetics and androgenic hormones will affect vascularity, as will ambient temperature."
"Vasomotor Vasomotor refers to actions upon a blood vessel which alter its diameter. More specifically, it can refer to vasodilator action and vasoconstrictor action. Sympathetic nerve fibers travel around the tunica media of the artery, secrete neurotransmitters such as norepinephrine into the extracellular fluid surrounding the smooth muscle (tunica media) from the terminal knob of the axon. The smooth muscle cell membranes have α and β-adrenergic receptors for these neurotransmitters. Activation of α-adrenergic receptors promotes vasoconstriction, while the activation of β-adrenergic receptors mediates the relaxation of muscle cells, resulting in vasodilation. Normally, α-adrenergic receptors predominates in smooth muscle of resistance"
"colchicine or dapsone. Cutaneous small-vessel vasculitis Cutaneous small-vessel vasculitis, also known as hypersensitivity vasculitis, cutaneous leukocytoclastic vasculitis, hypersensitivity angiitis, cutaneous leukocytoclastic angiitis, cutaneous necrotizing vasculitis and cutaneous necrotizing venulitis, is inflammation of small blood vessels (usually post-capillary venules in the dermis), characterized by palpable purpura. It is the most common vasculitis seen in clinical practice. ""Leukocytoclastic"" refers to the damage caused by nuclear debris from infiltrating neutrophils in and around the vessels. Initially red to pink, flat spots (formally, ""macules"") and raised bumps (formally, ""papules"") may be seen on the skin. Once fully developed, the classic appearance is ""non-blanching, palpable"
"Cardiovascular physiology Cardiovascular physiology is the study of the cardiovascular system, specifically addressing the physiology of the heart (""cardio"") and blood vessels (""vascular""). These subjects are sometimes addressed separately, under the names cardiac physiology and circulatory physiology. Although the different aspects of cardiovascular physiology are closely interrelated, the subject is still usually divided into several subtopics. Under most circumstances, the body attempts to maintain a steady mean arterial pressure. When there is a major and immediate decrease (such as that due to hemorrhage or standing up), the body can increase the following: In turn, this can have a significant impact"
"to atherosclerosis. Atherosclerosis is a form of arteriosclerosis (thickening and hardening of arterial walls), characterized by plaque deposits of lipids, fibrous connective tissue, calcium, and other blood substances. Atherosclerosis, by definition, affects only medium and large arteries (excluding arterioles). Macrovascular disease is associated with the development of coronary artery disease, peripheral vascular disease, brain attack (stroke), and increased risk of infection. Type 2 diabetes is more closely associated with macrovascular diseases than type 1 diabetes. Peripheral vascular disease and increased risk of infection have important implications in the care of the acutely ill patient. Macrovascular disease Macrovascular disease is a"
"disease remain active fields of biomedical research, with hundreds of scientific studies being published on a weekly basis. Recent areas of research include the link between inflammation and atherosclerosis the potential for novel therapeutic interventions, and the genetics of coronary heart disease. Cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. Cardiovascular disease includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, heart arrhythmia, congenital heart disease, valvular heart disease, carditis,"
"Vasomotion Vasomotion is the spontaneous oscillation in tone of blood vessel walls, independent of heart beat, innervation or respiration. While vasomotion was first observed by Jones in 1852, the complete mechanisms responsible for its generation and its physiological importance remain to be elucidated, however several hypotheses have been put forth. Intracellular calcium (Ca) concentration exhibits periodic oscillations in vascular smooth muscle cells. This is thought to result from Ca release from intracellular stores, due to inositol triphosphate and ryanodine-sensitive channel activation. This activation has been shown to result in either Ca ""sparks"", highly localized calcium increases, or ""waves"", global Ca"
"the tissues and were connected to the trachea. This was as a result of finding the arteries of cadavers devoid of blood. In medieval times, it was recognized that arteries carried a fluid, called ""spiritual blood"" or ""vital spirits"", considered to be different from the contents of the veins. This theory went back to Galen. In the late medieval period, the trachea, and ligaments were also called ""arteries"". William Harvey described and popularized the modern concept of the circulatory system and the roles of arteries and veins in the 17th century. Alexis Carrel at the beginning of the 20th century"
"it is called an organ system. The adjective ""visceral"", also ""splanchnic"", is used for anything pertaining to the internal organs. Historically, viscera of animals were examined by Roman pagan priests like the haruspices or the augurs in order to divine the future by their shape, dimensions or other factors. This practice remains an important ritual in some remote, tribal societies. The term ""visceral"" is contrasted with the term """", meaning ""of or relating to the wall of a body part, organ or cavity"" The two terms are often used in describing a membrane or piece of connective tissue, referring to"
"Vascular ring A vascular ring is a congenital defect in which there is an abnormal formation of the aorta and/or its surrounding blood vessels. The trachea and esophagus are completely encircled and sometimes compressed by a ""ring"" formed by these vessels, which can lead to breathing and digestive difficulties. Most often this is because of persistence of the double aortic arch after the second month of fetal life. The two arches surround the esophagus and trachea which, if sufficiently constrictive, may cause breathing or swallowing difficulties despite medical therapies. A less common ring is present with a right aortic arch"
"Vascular occlusion Vascular occlusion is a blockage of a blood vessel, usually with a clot. It differs from thrombosis in that it can be used to describe any form of blockage, not just one formed by a clot. When it occurs in a major vein, it can, in some cases, cause deep vein thrombosis. The condition is also relatively common in the retina, and can cause partial or total loss of vision. An occlusion can often be diagnosed using Doppler sonography (a form of ultrasound). Some medical procedures, such as embolisation, involve occluding a blood vessel to treat a particular"
"upon several other variables: Cardiovascular physiology Cardiovascular physiology is the study of the cardiovascular system, specifically addressing the physiology of the heart (""cardio"") and blood vessels (""vascular""). These subjects are sometimes addressed separately, under the names cardiac physiology and circulatory physiology. Although the different aspects of cardiovascular physiology are closely interrelated, the subject is still usually divided into several subtopics. Under most circumstances, the body attempts to maintain a steady mean arterial pressure. When there is a major and immediate decrease (such as that due to hemorrhage or standing up), the body can increase the following: In turn, this can"
"Revascularization In medical and surgical therapy, revascularization is the restoration of perfusion to a body part or organ that has suffered ischemia. It is typically accomplished by surgical means. Vascular bypass and angioplasty are the two primary means of revascularization. The term derives from the prefix re-, in this case meaning ""restoration"" and vasculature, which refers to the circulatory structures of an organ. It is often combined with ""urgent"" to form urgent vascularization. Revascularization involves a thorough analysis and diagnosis and treatment of the existing diseased vasculature of the affected organ, and can be aided by the use of different"
"system), perivisceral coelom, gonadal coelom and perihaemal coelom. Other terms sometimes used to refer to the water vascular system are ""ambulacral system"" and ""aquiferous system"". In the past, ""aquiferous system"" was also used to refer to many unrelated invertebrate structures, but today, it is restricted to water channels in sponges and the hydrostatic skeleton of some mollusks like ""Polinices"". In sea stars, water enters the system through a sieve-like structure on the upper surface of the animal, called the madreporite. This overlies a small sac, or ampulla, connected to a duct termed the stone canal, which is, as its name"
"Macrovascular disease Macrovascular disease is a disease of any large (""macro"") blood vessels in the body. It is a disease of the large blood vessels, including the coronary arteries, the aorta, and the sizable arteries in the brain and in the limbs. This sometimes occurs when a person has had diabetes for an extended period of time. Fat and blood clots build up in the large blood vessels and stick to the vessel walls. Three common macrovascular diseases are coronary disease (in the heart), cerebrovascular disease (in the brain), and peripheral vascular disease (in the limbs) Macrovascular disease (macroangiopathy) refers"
"and ""visceral"", surrounding a fluid filled space. The visceral layer of the membrane covers the organ (the viscera), and the parietal layer lines the walls of the body cavity (pariet- refers to a cavity wall). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity. For example, the pericardium is the serous cavity which surrounds the heart. Anatomical terminology Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors. Anatomical terminology uses many unique terms, suffixes, and prefixes deriving from Ancient Greek and Latin. These terms can"
"vascular plant species in the ecoregion, perhaps over 10,000, of which almost 20% are found nowhere else. The mix of flora depends on elevation, water levels and the influence of the sea. Many species are locally endemic, found only in small regions, so there is considerable diversity from one area to another. There are no endemic families, but several endemic genera. Some genera, such as ""Trianaeopiper"" and ""Cremosperma"", have many species. Generally the lowland rain forests in the north hold trees associated with cow tree (""Brosimum utile""), with groves of bongo (""Cavanillesia platanifolia""), wild cashew (""Anacardium excelsum""), Panama rubber (""Castilla"
"of the re-examinations of the men. In addition to the association with cognitive function already mentioned, there was evidence of an increase in ischaemic stroke in men whose sleep is frequently disturbed, and an association between daytime sleepiness and a significant increase in ischaemic heart disease. Many analyses of foods and dietary factors were conducted, as well as an examination of Helicobacter pylori and other infections, and vascular disease risk. A reduction in vascular disease mortality was found in those subjects most sexually active. Relationships between vascular disease and psychiatric symptoms, noise exposure, and hearing loss were also identified. Caerphilly"
"Neovascularization Neovascularization is the natural formation of new blood vessels (""neo-"" + ""vascular"" + ""-ization""), usually in the form of functional microvascular networks, capable of perfusion by red blood cells, that form to serve as collateral circulation in response to local poor perfusion or ischemia. Neovascularization is conventionally distinguished from angiogenesis in that angiogenesis is mainly characterized by the protrusion and outgrowth of capillary buds and sprouts from pre-existing blood vessels. Vasculogenesis can be synonymous with neovascularization but also often has reference instead to prenatal development and the initial embryologic formation of blood vessels. Growth factors that inhibit neovascularization include"
"Cerebrovascular disease Cerebrovascular disease includes a variety of medical conditions that affect the blood vessels of the brain and the cerebral circulation. Arteries supplying oxygen and nutrients to the brain are often damaged or deformed in these disorders. The most common presentation of cerebrovascular disease is an ischemic stroke or mini-stroke and sometimes a hemorrhagic stroke. Hypertension (high blood pressure) is the most important contributing risk factor for stroke and cerebrovascular diseases as it can change the structure of blood vessels and result in atherosclerosis. Atherosclerosis narrows blood vessels in the brain, resulting in decreased cerebral perfusion. Other risk factors"
"Vasa vasorum The vasa vasorum is a network of small blood vessels that supply the walls of large blood vessels, such as elastic arteries (e.g. aorta) and large veins (e.g. venae cavae). The name derives . Studies conducted with 3-dimensional microcomputed tomography (3D Micro-CT) on pig and human arteries from different vascular beds have shown that there are three different types of vasa vasorum: Depending on the type of vasa vasorum, it penetrates the vessel wall starting at the intimal layer (vasa vasorum interna) or the adventitial layer (vasa vasorum externa). Due to higher radial and circumferential pressures within the"
"Avascular necrosis Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on there may be no symptoms. Gradually joint pain may develop which may limit the ability to move. Complications may include collapse of the bone or nearby joint surface. Risk factors include bone fractures, joint dislocations, alcoholism, and the use of high-dose steroids. The condition may also occur without any clear reason. The most commonly affected bone is the femur. Other relatively common sites include the upper arm bone, knee, shoulder, and ankle. Diagnosis is typically"
"risk factors, calling into question vascular depression’s distinction from other depressive disorders. Vascular depression was defined in 1997 by Alexopoulos and colleagues, who theorized that cerebrovascular disease can put individuals at risk for the development or increase of depressive symptoms in older adults. Subcortical ischemic depression Subcortical ischemic depression, also known as vascular depression, is a medical condition most commonly seen in older people with major depressive disorder. Subcortical ischemic depression refers to vascular depression specifically due to lesions and restricted blood flow, known as ischemia, in certain parts of the brain. However, the disorder is typically described as vascular"
"Vasomotor center The vasomotor center (VMC) is a portion of the medulla oblongata that, together with the cardiovascular center and respiratory center, regulates blood pressure and other homeostatic processes. Vasomotor center is a fairly archaic term since this function relies not on a single brain structure (""center"") but rather represents a presympathetic network of interacting neurons. Upon increase in carbon dioxide level at central chemoreceptors, it stimulates the sympathetic system to constrict vessels. This is opposite to carbon dioxide in tissues causing vasodilatation, especially in the brain. Cranial nerves IX (Glossopharyngeal nerve) and X Vagus nerve both feed into the"