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Cerebral Aneurysm
An intracranial aneurysm, also known as a brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. Aneurysms in the posterior circulation (basilar artery, vertebral arteries and posterior communicating artery) have a higher risk of rupture. Basilar artery aneurysms represent only 3–5% of all intracranial aneurysms but are the most common aneurysms in the posterior circulation. Classification Cerebral aneurysms are classified both by size and shape. Small aneurysms have a diameter of less than 15 mm. Larger aneurysms include those classified as large (15 to 25 mm), giant (25 to 50 mm), and super-giant (over 50 mm). Berry (saccular) aneurysms Saccular aneurysms, also known as berry aneurysms, appear as a round outpouching and are the most common form of cerebral aneurysm. Causes include connective tissue disorders, polycystic kidney disease, art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basilar Artery
The basilar artery () is one of the arteries that supplies the brain with oxygen-rich blood. The two vertebral arteries and the basilar artery are known as the vertebral basilar system, which supplies blood to the posterior part of the circle of Willis and joins with blood supplied to the anterior part of the circle of Willis from the internal carotid arteries. Structure The basilar artery arises from the union of the two vertebral arteries at the junction between the medulla oblongata and the pons between the abducens nerves (CN VI). The diameter of the basilar artery range from 1.5 to 6.6 mm. It ascends superiorly in the basilar sulcus of the ventral pons and divides at the junction of the midbrain and pons into the posterior cerebral arteries. Its branches from caudal to rostral include: *anterior inferior cerebellar artery *labyrinthine artery (<15% of people, usually branches from the anterior inferior cerebellar artery) * |
Cerebral Artery
The cerebral arteries describe three main pairs of arteries and their branches, which perfuse the cerebrum of the brain. The three main arteries are the: * ''Anterior cerebral artery'' (ACA) * ''Middle cerebral artery'' (MCA) * ''Posterior cerebral artery'' (PCA) Both the ACA and MCA originate from the cerebral portion of internal carotid artery, while PCA branches from the intersection of the posterior communicating artery and the anterior portion of the basilar artery. The three pairs of arteries are linked via the anterior communicating artery and the posterior communicating arteries In human anatomy, the left and right posterior communicating arteries are arteries at the base of the brain that form part of the circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and W .... All three arteries send out arteries that perforate brain in the medial central portions prior to branching and bifurcating further. The arteries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Units (SI) equalling (SI standard prefix "micro-" = ); that is, one millionth of a metre (or one thousandth of a millimetre, , or about ). The nearest smaller common SI unit is the nanometre, equivalent to one thousandth of a micrometre, one millionth of a millimetre or one billionth of a metre (). The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria, and for grading wool by the diameter of the fibres. The width of a single human hair ranges from approximately 20 to . The longest human chromosome, chromosome 1, is approximately in length. Examples Between 1 μm and 10 μm: * 1–10 μm – length of a typical bacterium * 3–8 μm – width of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charcot–Bouchard Aneurysm
Charcot–Bouchard aneurysms are aneurysms of the brain vasculature which occur in small blood vessels (less than 300 micrometre diameter). Charcot–Bouchard aneurysms are most often located in the lenticulostriate vessels of the basal ganglia and are associated with chronic hypertension. Charcot–Bouchard aneurysms are a common cause of cerebral hemorrhage. Retinal microaneurysms are seen in conditions like diabetic retinopathy, HIV related retinal microangiopathy, sickle cell retinopathy, idiopathic macular telangiectasia etc. In diabetic retinopathy, due to breakdown in blood–retinal barrier, microaneurysms may leak plasma constituents into the retina, or it may thrombose. Signs and symptoms If a Charcot–Bouchard aneurysm ruptures, it will lead to an intracerebral hemorrhage, which can cause hemorrhagic stroke, typically experienced as a sudden focal paralysis or loss of sensation. Pathophysiology Charcot–Bouchard aneurysms are aneurysms in the small penetrati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intracranial Dolichoectasias
The term dolichoectasia means elongation and distension. It is used to characterize arteries throughout the human body which have shown significant deterioration of their tunica intima (and occasionally the tunica media), weakening the vessel walls and causing the artery to elongate and distend. Signs and symptoms Vertebrobasillar dolichoectasia * Hemifacial spasm * Paresis * Trigeminal neuralgia Internal carotid dolichoectasia * Progressive visual field defect Cause Most commonly caused by hypertension, continued stress on the walls of the artery will degrade the vessel wall by damaging and loosening the collagen and elastin meshwork which comprises the intima. Similarly, hypercholesterolemia or hyperlipidemia can also provide sufficient trauma to the vessel wall resulting in dolichoectasia. As the arrangement of connective tissue is disturbed, the vessel wall is no longer able to hold its original conformation and begins to unravel due to the continued hypertension. High ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteremia
Bloodstream infections (BSIs), which include bacteremias when the infections are bacterial and fungemias when the infections are fungal, are infections present in the blood. Blood is normally a sterile environment, so the detection of microbes in the blood (most commonly accomplished by blood cultures) is always abnormal. A bloodstream infection is different from sepsis, which is the host response to bacteria. Bacteria can enter the bloodstream as a severe complication of infections (like pneumonia or meningitis), during surgery (especially when involving mucous membranes such as the gastrointestinal tract), or due to catheters and other foreign bodies entering the arteries or veins (including during intravenous drug abuse). Transient bacteremia can result after dental procedures or brushing of teeth. Bacteremia can have several important health consequences. The immune response to the bacteria can cause sepsis and septic shock, which has a high mortality rate. Bacteria c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertension
Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high blood pressure, however, is a major risk factor for stroke, coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, chronic kidney disease, and dementia. Hypertension is a major cause of premature death worldwide. High blood pressure is classified as primary (essential) hypertension or secondary hypertension. About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. Lifestyle factors that increase the risk include excess salt in the diet, excess body weight, smoking, and alcohol use. The remaining 5–10% of cases are categorized as secondary high blood pressure, defined as high blood pressure due to an identifiable cause, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycystic Kidney Disease
Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These cysts may begin to develop in utero, in infancy, in childhood, or in adulthood. Cysts are non-functioning tubules filled with fluid pumped into them, which range in size from microscopic to enormous, crushing adjacent normal tubules and eventually rendering them non-functional as well. PKD is caused by abnormal genes that produce a specific abnormal protein; this protein has an adverse effect on tubule development. PKD is a general term for two types, each having their own pathology and genetic cause: autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD). The abnormal gene exists in all cells in the body; as a result, cysts may occur in the liver, seminal vesicles, and pancreas. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Aneurysm NIH
Cerebral may refer to: * Of or relating to the brain * Cerebrum, the largest and uppermost part of the brain * Cerebral cortex, the outer layer of the cerebrum * Retroflex consonant, also referred to as a cerebral consonant, a type of consonant sound used in some languages * Intellectual An intellectual is a person who engages in critical thinking, research, and reflection about the reality of society, and who proposes solutions for the normative problems of society. Coming from the world of culture, either as a creator or a ..., rather than emotional See also * {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Communicating Artery
In human anatomy, the left and right posterior communicating arteries are arteries at the base of the brain that form part of the circle of Willis. Each posterior communicating artery connects the three cerebral arteries of the same side. Anteriorly, it connects to the internal carotid artery (ICA) prior to the terminal bifurcation of the ICA into the anterior cerebral artery and middle cerebral artery. Posteriorly, it communicates with the posterior cerebral artery. The brain is supplied with blood by the internal carotid arteries and also by the posterior cerebral arteries; the posterior communicating arteries connects the two systems. This provides redundancies or collaterals in the cerebral circulation so that, if one system is blocked or narrowed, the other can take over. Development The development of the posterior cerebral artery (PCA) in the fetal brain occurs relatively late and arises from the fusion of several embryonic vessels near the caudal end of the posterior com ... [...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. 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 impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions. The following description is based on ideali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aneurysm
An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus (starting point) for clot formation (thrombosis) and embolization. As an aneurysm increases in size, the risk of rupture, which leads to uncontrolled bleeding, increases. Although they may occur in any blood vessel, particularly lethal examples include aneurysms of the Circle of Willis in the brain, aortic aneurysms affecting the thoracic aorta, and abdominal aortic aneurysms. Aneurysms can arise in the heart itself following a heart attack, including both ventricular and atrial septal aneurysms. There are congenital atrial septal aneurysms, a rare heart defect. Etymology The word is from Greek: ἀνεύρυσμα, aneurysma, "dilation", from ἀνευρύνειν, aneurynein, "to dilate". Classification Aneurysms are classified by type, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
