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40. Cerebral circulation. The concept of “blood-brain barrier”: Difference between revisions

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(Created page with "== Cerebral circulation == The cerebral circulation supplies the brain with blood. It originates from four large arteries, two carotid and two vertebral arteries. These four arteries form a structure called the ''circle of Willis'' at the base of the brain. From the circle of Willis arteries which supply the brain originate. The brain constitutes about 2% of the body weight, but it receives 15% of cardiac output in rest, around 700 mL/min. === Regulation of cerebral ci...")
 
 
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The cerebral circulation also redirects blood flow to the more active parts of the brain. For example, when speaking the “speaking centre” of the brain will receive more blood flow, at the expense of other brain areas.
The cerebral circulation also redirects blood flow to the more active parts of the brain. For example, when speaking the “speaking centre” of the brain will receive more blood flow, at the expense of other brain areas.


== Blood brain barrie ==
== Blood brain barrier ==
The blood brain barrier is a barrier between the blood and the brain. Its function is to prevent toxic molecules in the blood from entering the brain. Almost all parts of the brain are protected by the blood brain barrier, except for a few parts. These uncovered parts are called the ''circumventricular organs'' and include the area postrema, the pineal gland and the neural lobe of the pituitary gland, and some others. The circumventricular organs need to receive unfiltered blood for various reasons.
The blood brain barrier is a barrier between the blood and the brain. Its function is to prevent toxic molecules in the blood from entering the brain. Almost all parts of the brain are protected by the blood brain barrier, except for a few parts. These uncovered parts are called the ''circumventricular organs'' and include the area postrema, the pineal gland and the neural lobe of the pituitary gland, and some others. The circumventricular organs need to receive unfiltered blood for various reasons.