Homo Sapiens Sapiens
Our brain is irrigated by a set of main
arteries, which then branch to form the Willis Polygon. This arrangement allows the blood to pass by
other artery when another is blocked conserving
the circulation in the brain avoiding problems with its oxidation. Each artery
heads towards the lobe nursing them, branching to the centre of the brain while
decreasing the diameter of the vases.
Carotid sinuses are the small dilatations in the internal carotid arteries. They contain the baroreceptors which detect the variations in the blood pressure and transmit this information to the CNS. The intimate and adventitia tunics are very rich in nerve endings and the tunica media is the thinnest of the three The pulses of afferent nerves are processed by the brain in order to control the vasoconstriction and stabilize the blood pressure. When the baroreceptors are stimulated the vases related hormones are produced.
In people with hypertension the baroreceptors became less sensitive to the changes in the blood pressure, and this continues to increase.
In the brain the capillaries are continuous so they can protect the organ from aggressive agents and do not possess pinocytosis vesicles.
Arteriovenous anastomoses are direct communications between arterioles and venules. Changes in the diameter of the vases modify the blood pressure and the blood flux. These anastomoses are richly innervated for parasympatic and simpatic terminations.
An aneurysm is fragility in the walls of some arteries of the brain, which became larger. It tends to localize in the Willis Circle.
In the brain the capillaries are continuous so they can protect the organ from aggressive agents and do not possess pinocytosis vesicles.
Arteriovenous anastomoses are direct communications between arterioles and venules. Changes in the diameter of the vases modify the blood pressure and the blood flux. These anastomoses are richly innervated for parasympatic and simpatic terminations.
An aneurysm is fragility in the walls of some arteries of the brain, which became larger. It tends to localize in the Willis Circle.