1.The internal carotid artery and vertebral artery form a willis ring at the base of the brain 2.The artery that enters the cranial cavity forms and its bend, which is the main reason why the cerebral artery has no pulsation 3.The cerebral artery wall is very thin, similar to the extracranial vein of the same size 4.It is divided into cortical branches and central branches, which form a system and do not anastomose with each other 5.The cortical artery forms a rich anastomosis in the soft membrane and forms a blood balance pool on the surface of the brain, but the resulting 6.Arteries and veins do not travel together. 7.Venous and venous sinuses do not have valves. 8.Capillaries vary in density in different brain regions and are related to brain function. 9.Brain capillaries and neurons are separated by a blood-brain barrier. 10.There are many variants in brain vessels, especially in the cerebral base arterial ring.