A stroke is the acute neurologic injury that come as a result of an effect of ischemia or haemorrhage of the encephalon. Ischemia is caused by diminished supply of arterial blood which carries sugar and oxygen to brain tissue. Haemorrhagic stroke is due to intracerebral or subarachnoid bleeding and it damages the brain directly at the site of the bleeding by compressing the encircling tissue. Ischemic strokes can be embolic or thrombotic. Thrombotic stroke consequences from clot formation in the arterial blood vessel that provides blood to the encephalon, and can bear upon either large vessel or small vessel.
Small vessel disease affects the intracerebral arterial system. A stroke due to impedimenta of these vessels is referred to as a lacunar infarction. Lacunar infarctions are small (0 2 to 15 millimeter in diameter) noncortical infarctions caused by occlusion of a single penetrating branch of a large cerebral arterial blood vessel. Lacunar stroke has 5 classic syndromes and motor stroke is the most syndrome. The typical presentation is hemiparesis of face, arm or leg of one side. Clinical symptoms of stroke are slurred speech, right hand numbness, weak right mitt grip, and right sided facial palsy.(health direct, 2014)and most common among ischemic strokes (Rathore, Hinn, Cooper, Tyroler, & Rosamond, 2002).
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Mechanisms of ischemic cell injury and death
There is progressive vasoconstriction of arterioles until the BP exceeds the upper limit of auto regulation, followed by breakthrough vasodilation, increase in cerebral blood flow, blood-brain barrier dysfunction, and cerebral oedema(Rodriguez-Yanez et al., 2006). Cerebral ischemia results in severely ischemic tissue with failure of electrical activity and ionic pumps (Rodriguez-Yanez et al., 2006) There is increase in the release of the excitatory amino acid glutamate due to electrical failure. (Rodriguez-Yanez et al., 2006) . Glutamate receptors are activated as a result and cause the opening of ion channels that allow potassium ions to leave the cell and sodium and calcium ions to enter. This has a number of physiological effects.
The above events end in cell death, including depletion of ATP, changes in ionic concentrations of sodium, potassium, and calcium, increased lactate, acidosis, accumulation of oxygen free radicals, intracellular accumulation of water, and activation of proteolytic processes.(Deb, Sharma, & Hassan, 2010). Surrounding this is the penumbra(Rodriguez-Yanez et al., 2006)
Different cellular signaling pathways respond to calcium levels. The inflow of calcium resulting from glutamate receptor stimulation leads to their activation.
7. Lee, C.-Y., Chen, C.-C., & Liou, H.-H. (2009). Levetiracetam inhibits glutamate transmission through presynaptic P/Q-type calcium channels on the granule cells of the dentate gyrus. British Journal of Pharmacology, 158(7), 1753-1762. doi: 10.1111/j.1476-5381.2009.00463.x
Ischemic Stroke is caused due to a blood clot in an area of the brain, leading to loss of neural function if last for more than 24 hours. In the United States, ischemic stroke affects 2.7% of men and 2.5% of women of age range 18 years and older. In addition, it has reported that annually about 610,000 and 185,000 of new strokes and recurrent strokes cases occur in US1. Moreover, it has reported that patients who have suffered from a stroke have more chances of recurrent stroke, Myocardial infarction, and death from vascular causes2. One of the risk factor of ischemic stroke is formation of plaque in the blood vessels causing blood clot3. Several randomized trials have also reported that antiplatelet medications are efficient in preventing recurrences of stroke in patients who had an incident of ischemic stroke. Antiplatelet medications for preventing recurrences of stroke are aspirin, combination of aspirin and extended-release dipyridamole, and clopidogrel alone4. It ha...
Scientists are on the brink of doing the unthinkable-replenishing the brains of people who have suffered strokes or head injuries to make them whole again. If that is not astonishing enough, they think they may be able to reverse paralysis. The door is at last open to lifting the terrifying sentence these disorders still decree-loss of physical function, cognitive skills, memory, and personality.
Cerebrovascular Accident a) Overview - definition and the effects of the stroke on the body A stroke is a serious, life-threatening medical condition that occurs when the blood supply to part of the brain is cut off. (http://www.nhs.uk/conditions/Stroke/Pages/Introduction.aspx) This condition is a common cause of death and disability, especially in older people. Some predisposing factors include: • hypertension • atheroma • cigarette smoking • diabetes mellitus It occurs when blood flow to the brain suddenly interrupted, causing hypoxia. The effects include paralysis of a limb or one side of the body and disturbances of speech and vision.
Due to the lose in brain cells sometime facial nerve can become damage. Which is also a sign of a stroke. In stroke patient usually when ask to smile, only half of their facial muscle would be able to do so. While the other half remain drooped. The Circulatory system is affect as well. Remember in a Hemorrhagic stroke a ruptured blood vessel begins to bleed out into the brain. Once blood is secreted out side the blood vessel into the tissues, red blood cells will take away nutrient from the brain cells. In Ischemic, the blockage in the blood vessel does not allow the blood to circulated proper. As a result of lost blood supply brain cells will die in the area where it is not receiving nourishment. Traveling in our bloodstream is oxygen and glucose, which is constantly need for cells to preform they daily functions.
the muscles lose their ability to respond to the brain and results in the inability to feel
Stroke occurs when the blood supply to the brain is blocked or condensed. Blood works to transport oxygen and other beneficial substances to the body’s cells and organs, as well as the brain. There are two main types of strokes that are known as Ischemic strokes and Hemorrhagic strokes. When the blood vessels that provides for the brain becomes congested, is it referred to as ischemic stroke, the most common stroke within adults. Blood clots, a cluster of blood that sticks together, are the cause of Ischemic strokes. Ischemic strokes also takes place when arteries become backed up with plague, leaving less blood to flow. Plague is cholesterol, calcium and fibrous and connective tissue that sticks to the walls of blood vessels. Ischemic strokes eternally damage the brain and cause a person's body to no longer function habitually.Some risk factors that may increase stroke are high cholesterol, diabetes, high blood pressure, and obesity. Some stroke factors are also due to old age or having a family that has a history of strokes. Men are more likely to have a stroke but the most st...
The bleeding of the brain also causes increased pressure on the brain and it presses against the skull. Symptoms of a hemorrhagic stroke vary upon the amount of blood tissues affected and the location of the bleeding. A transient ischemic attack only lasts for a few hours of the day or a day and it doesn't cause permanent brain damage like an ischemic stroke would. (TIA) transient ischemic attack is not considered to be a stroke, it is referred to as a warning signal before having a stroke. Ask yourself how does a stroke change a person's everyday life drastically? People who suffer from strokes have to live with a mental or physical disability that causes them to be limited.
So, what is actually happening when a stroke occurs? A stroke occurs blood flow to the brain is either impeded or significantly reduced. When this happens, the brain cells are starved of the essential oxygen and nutrients they need and begin to die. There are three different kinds of strokes. They are ischemic, hemorrhagic,
The simplest way in which neurotransmitter-receptor binding can cause the opening of the protein channels is when the receptor is located immediately on top of the protein channel. Once a neurotransmitter binds on to the receptor, it causes the protein channel to permit ion flow. Receptors can also be acting on protein channels in more indirect fashion, via a second messenger system. A second messenger system is characterized by a G Protein's inclusion in the transduction of "signals from the transmembrane receptors to intracellular effectors." (1) That means, the binding of a neurotransmitter to a receptor activates a G Protein, which causes the protein channels gating ion flow to open. For this, two general mechanisms exist. Before they can be explained, however, the structure and dynamics of the G Protein must be considered.
The World Health Organisation (2013) explains that an Ischaemic stroke occurs as a result of a blood vessel becoming blocked by a clot, reducing the supply of oxygen to the brain and, therefore, damaging tissue. The rationale for selecting Mary for this discussion is; the author wishes to expand her evidenced based knowledge of stroke since it is the principal cause of disability and the third leading cause of mortality within the Scottish population (Scottish Intercollegiate Guidelines Network (SIGN), 2008) and, therefore, a national priority. In response to this priority, the Scottish Government (2009) produced their ‘Better Heart Disease and Stroke Care Action Plan’. Additionally, they have introduced a HEAT target to ensure 90% of stroke patients get transferred to a specialised stroke unit on the day of admission to hospital (Scottish Government, 2012).
“Time is brain” is the repeated catch phrase when addressing the treatment and management of stroke (Saver, 2006). Access to prompt and appropriate medical care during the first few hours of stroke onset is critical to patient survival and outcomes. Recent changes in the guidelines for acute stroke care released by the American Heart Association (AHA) and the American Stroke Association (ASA) have improved patient access to treatment. Stroke treatment now follows the model of myocardial infarction treatment. Hospitals are categorized into four levels based on stroke treatment capability. The most specialized treatment is available in comprehensive stroke centers followed by primary stroke centers, acute stroke-ready hospitals, and community hospitals. The use of telemedicine now enables even community hospitals, with limited specialized capabilities, to care for stroke patients. Telemedicine puts emergency hospital personnel in contact with neurologists providing expertise in the evaluation of a stroke patient and determination of their eligibility for treatment with thrombolytic medication (Jefferey, 2013).
Stroke is a serious medical condition that affects people of all ages specifically older adults. People suffer from a stroke when there is decreased blood flow to the brain. Blood supply decreases due to a blockage or a rupture of a blood vessel which then leads to brain tissues dying. The two types of stroke are ischemic stroke and hemorrhagic stroke. An ischemic stroke is caused by a blood clot blocking the artery that brings oxygenated blood to the brain. On the other hand, a hemorrhagic stroke is when an artery in the brain leaks or ruptures (“About Stroke,” 2013). According to the Centers for Disease Control and Prevention (CDC), “Stroke is the fourth leading cause of death in the United States and is a major cause of adult disability” (“About Stroke,” 2013). Stroke causes a number of disabilities and also leads to decreased mobility in over half of the victims that are 65 and older. The CDC lists several risk factors of stroke such as heredity, age, gender and ethnicity as well as medical conditions such as high blood pressure, high cholesterol, diabetes and excessive weight gain that in...
Sometimes neurons are negatively influenced by the voltage-gated sodium channels’ loss of ability. Tetrodotoxin (TTX) and saxitoxin are two of the deadliest poisons in the world, found in pufferfish and poison dart frogs, respectively. The reason they are so dangerous is that they block only voltage-gated sodium channels (as opposed to blocking both sodium and potassium channels, as done by medical anesthetics), and therefore completely throw off the relationship between the sodium channels and the potassium channels, and therefore the balance between concentrations of Na+ and K+
I realized it was a stroke,” –Fred, a stroke survivor. Some of the most common symptoms indicating that a stroke is occurring include sudden numbness or loss of movement in the limbs on one side of your body or face, sudden vision changes, sudden trouble speaking, sudden confusion, a very intense headache, or sudden balance issues. Stroke is simply acquired when the blood supply to the brain is suspended, but to get to the roots of what causes it, a stroke is triggered by the slowly forming plaque buildup over time. The plaque is made up of calcium, fat, cholesterol, cellular waste, and fibrin, a material involved in blood clotting. The plaque existing in an artery can grow big enough to block the supply of blood to the brain, resulting in a stroke. A stroke can also be caused by high blood pressure breaking a blood vessel in the brain causing internal bleeding. Although there is no cure, as damage the brain is usually irreversible if not cared for quickly; there are different treatments available for both types of stroke. For an ischemic stroke, a tissue called plasminogen activator can be injected into an artery to break up