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Cerebral Embolism
An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule ( fat embolism), a bubble of air or other gas (gas embolism), amniotic fluid (amniotic fluid embolism), or foreign material. An embolism can cause partial or total blockage of blood flow in the affected vessel. Such a blockage (vascular occlusion) may affect a part of the body distant from the origin of the embolus. An embolism in which the embolus is a piece of thrombus is called a thromboembolism. An embolism is usually a pathological event, caused by illness or injury. Sometimes it is created intentionally for a therapeutic reason, such as to stop bleeding or to kill a cancerous tumor by stopping its blood supply. Such therapy is called embolization. Classification There are different types of embolism, some of which are listed below. Embolism can be classified based on where it enters the circulation, either in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrograph
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 which is also taken on a microscope but is only slightly magnified, usually less than 10 times. Micrography is the practice or 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 widely used in all fields of microscopy. Types Photomicrograph 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 simply by connecting a camera to a microscope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemostasis
In biology, hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). It is the first stage of wound healing. This involves coagulation, which changes blood from a liquid to a gel. Intact blood vessels are central to moderating blood's tendency to form clots. The endothelial cells of intact vessels prevent blood clotting with a heparin-like molecule and thrombomodulin, and prevent platelet aggregation with nitric oxide and prostacyclin. When endothelium of a blood vessel is damaged, the endothelial cells stop secretion of coagulation and aggregation inhibitors and instead secrete von Willebrand factor, which initiate the maintenance of hemostasis after injury. Hemostasis involves three major steps: * vasoconstriction * temporary blockage of a hole in a damaged blood vessel by a platelet plug * blood coagulation (formation of fibrin clots) These processes seal the inju ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotid Artery , an artery on each side of the head and neck supplying blood to the brain
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Carotid artery may refer to: * Common carotid artery, often "carotids" or "carotid", an artery on each side of the neck which divides into the external carotid artery and internal carotid artery * External carotid artery, an artery on each side of the head and neck supplying blood to the face, scalp, skull, neck and meninges * Internal carotid artery The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest. In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 14–16 billion neurons, and the estimated number of neurons in the cerebellum is 55–70 billion. Each neuron is connected by synapses to several thousand other neurons. These neurons typically communicate with one another by means of long fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells. Physiologically, brains exert centralized control over a body's other organs. They act on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infarction
Infarction is tissue death ( necrosis) due to inadequate blood supply to the affected area. It may be caused by artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct (from the Latin ''infarctus'', "stuffed into"). Causes Infarction occurs as a result of prolonged ischemia, which is the insufficient supply of oxygen and nutrition to an area of tissue due to a disruption in blood supply. The blood vessel supplying the affected area of tissue may be blocked due to an obstruction in the vessel (e.g., an arterial embolus, thrombus, or atherosclerotic plaque), compressed by something outside of the vessel causing it to narrow (e.g., tumor, volvulus, or hernia), ruptured by trauma causing a loss of blood pressure downstream of the rupture, or vasoconstricted, which is the narrowing of the blood vessel by contraction of the muscle wall rather than an external force (e.g., cocaine vasoconstriction le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arterial Embolism
Arterial embolism is a sudden interruption of blood flow to an organ or body part due to an embolus adhering to the wall of an artery blocking the flow of blood, the major type of embolus being a blood clot (thromboembolism). Sometimes, pulmonary embolism is classified as arterial embolism as well,MedlinePlus > Arterial embolismSean O. Stitham, MD and David C. Dugdale III, MD. Also reviewed by David Zieve, MD. Reviewed last on: 5/8/2008. Alternative link/ref> in the sense that the clot follows the pulmonary artery carrying deoxygenated blood away from the heart. However, pulmonary embolism is generally classified as a form of venous embolism, because the embolus forms in veins. Arterial embolism is the major cause of infarction (which may also be caused by e.g. arterial compression, rupture or pathological vasoconstriction). Signs and symptoms Symptoms may begin quickly or slowly depending on the size of the embolus and how much it blocks the blood flow. Symptoms of embolisation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Vein Thrombosis
Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enlarged veins in the affected area, but some DVTs have no symptoms. The most common life-threatening concern with DVT is the potential for a clot to embolize (detach from the veins), travel as an embolus through the right side of the heart, and become lodged in a pulmonary artery that supplies blood to the lungs. This is called a pulmonary embolism (PE). DVT and PE comprise the cardiovascular disease of venous thromboembolism (VTE). About two-thirds of VTE manifests as DVT only, with one-third manifesting as PE with or without DVT. The most frequent long-term DVT complication is post-thrombotic syndrome, which can cause pain, swelling, a sensation of heaviness, itching, and in severe cases, ulcers. Recurrent VTE occurs in about 30% of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Artery
A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and the smallest ones are the arterioles, which lead to the capillaries that surround the pulmonary alveoli. Structure The pulmonary arteries are blood vessels that carry systemic venous blood from the right ventricle of the heart to the microcirculation of the lungs. Unlike in other organs where arteries supply oxygenated blood, the blood carried by the pulmonary arteries is deoxygenated, as it is venous blood returning to the heart. The main pulmonary arteries emerge from the right side of the heart, and then split into smaller arteries that progressively divide and become arterioles, eventually narrowing into the capillary microcirculation of the lungs where gas exchange occurs. Pulmonary trunk In order of blood flow, the pulmonary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Embolism
Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream ( embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing in, and coughing up blood. Symptoms of a blood clot in the leg may also be present, such as a red, warm, swollen, and painful leg. Signs of a PE include low blood oxygen levels, rapid breathing, rapid heart rate, and sometimes a mild fever. Severe cases can lead to passing out, abnormally low blood pressure, obstructive shock, and sudden death. PE usually results from a blood clot in the leg that travels to the lung. The risk of blood clots is increased by advanced age, cancer, prolonged bed rest and immobilization, smoking, stroke, long-haul travel over 4 hours, certain genetic conditions, estrogen-based medication, pregnancy, obesity, trauma or bone fracture, and after some types of surgery. A small proportion of cases are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systemic Circulation
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek ''kardia'' meaning ''heart'', and from Latin ''vascula'' meaning ''vessels''). The circulatory system has two divisions, a systemic circulation or circuit, and a pulmonary circulation or circuit. Some sources use the terms ''cardiovascular system'' and ''vascular system'' interchangeably with the ''circulatory system''. The network of blood vessels are the great vessels of the heart including large elastic arteries, and large veins; other arteries, smaller arterioles, capillaries that join with venules (small veins), and other veins. The circulatory system is closed in vertebrates, which means that the blood never leaves the network of blood vessels. Some invertebrates such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veins
Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart. Veins are less muscular than arteries and are often closer to the skin. There are valves (called ''pocket valves'') in most veins to prevent backflow. Structure Veins are present throughout the body as tubes that carry blood back to the heart. Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small. * Superficial veins are those closer to the surface of the body, and have no corresponding arteries. *Deep veins are deeper in the body and have corresponding arteries. *Perforator veins drain from the superficial to the deep veins. These are usually referred to in the lower limbs and feet. * Commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
