Yup! Your brain sits in a bath not of blood, but a different substance called cerebrospinal fluid (CSF). It is on the "internal' side of the blood brain barrier. Nutrients and water diffuse across the blood brain barrier through very fine capillaries. Blood is too thick and "sticky" for the brain to be able to use while still performing its role. CSF itself is almost entirely water - about 99%. CSF also serves to cushion your brain and act as an immunological barrier between your brain and the rest of your body.

In addition, most organs are adversely affected by direct contact with blood. You don't want blood in your stomach or kidneys or liver either! Blood is meant to stay in your blood vessels and diffuse nutrients across various tissue barriers while the glymphatic / lymphatic systems draw metabolic and immunologic waste away to be excreted.