Blood Circulation Blockage.

Blood Circulation Blockage. The mind gets about 25 % of the body's oxygen but cannot hold it. Brain cells need continuous oxygen supply to remain healthy and function properly. Therefore, blood needs to be provided regularly to the brain through 2 primary arterial devices:

https://www.youtube.com/watch?v=w1q2fAQOkzE

???????? The carotid arteries come up through either side of the front of the neck. (To feel the pulse of a carotid artery, place your fingertips gently against either side of your neck, right under the jaw.)

???????? The basilar artery forms at the base of our skull, starting from the vertebral arteries, which run up along the spine, join, and come up through the rear of the neck.

The artery at the base of the brain is the joining area of several routes at the brain's bottom (inferior) side. At the street that sits at the base of the brain, the internal carotid arteries branch into smaller arteries that supply oxygenated blood to over 80% of the cerebrum.

A reduction of, or disruption in, blood flow to the brain is the cause of a stroke. Blockage for even a short period can be disastrous and cause brain damage or even death.

?Ischemic (caused by a blockage in an artery)

?Hemorrhagic (caused by a tear in the artery's wall that produces bleeding into or around the brain)

The consequences of a stroke, the type of functions affected, and the severity, depending on where in the brain it has occurred and the extent of the damage.

Ischemic strokes are by far the more common type, causing over 80% of all strokes. Ischemia means the deficiency of oxygen in vital tissues. Ischemic strokes are caused by blood clots that are usually one of three types:

Thrombotic or Large-Artery Stroke and Atherosclerosis. Thrombotic stroke accounts for about 60% of all strokes. It usually occurs when an artery to the brain is blocked by a thrombus (blood clot) that forms due to atherosclerosis (commonly known as the hardening of the arteries). These strokes are also sometimes referred to as large-artery strokes. The process leading to thrombotic stroke is complex and occurs over time:

The arterial walls slowly thicken, harden, and narrow until blood flow is reduced, a condition known as stenosis.

As these processes continue, blood flow slows. In addition, other events contribute to the coming stroke: The arteries become calcified, lose elasticity, and become susceptible to tearing. In this event, the thrombus (blood clot) forms. The blood clot then blocks the already narrowed artery and shuts off oxygen to part of the brain. A stroke occurs.

Embolic Strokes and Atrial Fibrillation. An embolic stroke is usually caused by a dislodged blood clot that has travelled through the blood vessels (an embolus ) until it becomes wedged in an artery. Embolic strokes may be due to various conditions:

?In about 15% of embolic strokes, the blood clots initially form due to a rhythm disorder known as atrial fibrillation. Emboli can originate from blood clots at the site of artificial heart valves. Patients with heart valve disorders such as mitral stenosis are at increased risk for clots when they also have atrial fibrillation.? Emboli can also occur after a heart attack or in association with heart failure.

Rarely are emboli formed from fat particles, tumour cells, or air bubbles that travel through the bloodstream.

Lacunar Strokes. Lacunar infarcts are a series of very tiny, ischemic strokes which cause clumsiness, weakness, and emotional variability. They make up the majority of silent brain infarctions and are probably a result of chronic high blood pressure. They are a subtype of thrombotic stroke. They can also sometimes serve as warning signs for a major stroke.

Silent Brain Infarctions. Many elderly people have silent brain infarctions, small strokes that cause no apparent symptoms. They are detected in up to half of elderly patients who undergo imaging tests for problems other than stroke. The presence of silent infarctions indicates an increased risk for future stroke and is often a contributor to mental impairment in the elderly. Smokers and people with hypertension are at particular risk.

Transient Ischemic Attacks (TIAs)

A transient ischemic attack (TIA) is an episode in which a person has stroke-like symptoms for less than 24 hours, usually less than 1-2 hours. Transient ischemic attacks (TIAs) are caused by tiny emboli (clots often formed of pieces of calcium and fatty plaque) that lodge in an artery to the brain. They typically break up quickly and dissolve, but they temporarily block the blood supply to the brain.

A TIA is often considered a warning sign that a proper stroke may happen in the future if something is not done to prevent it. TIA should be taken very seriously and treated as aggressively as a stroke.

Hemorrhagic Stroke

About 20% of strokes occur from haemorrhage (sudden bleeding) into or around the brain. While hemorrhagic strokes are less common than ischemic strokes, they tend to be more deadly.

Hemorrhagic strokes are categorised by how and where they occur.

? Parenchymal, or intracerebral, hemorrhagic strokes. These strokes occur from bleeding within the brain tissue. They are most often the result of high blood pressure exerting excessive pressure on arterial walls already damaged by atherosclerosis. Heart attack patients who have been given drugs to break up blood clots or blood-thinning drugs have a slightly elevated risk of this type of stroke.