The vertebrate brain is in all of the brain systems that are found in mammals and occur in birds, reptiles, and amphibians, as well as in fish and sharks.
2. The part of the brain developed from the middle cerebral vesicle (hollow organ in the body containing fluid) and consisting of the tectum (part in the body that forms a covering; especially, the back upper section of the midbrain) and cerebral peduncles (neurons joining different parts of the brain), and traversed by the cerebral aqueduct.
The cerebral aqueduct is a narrow opening in the brain that connects the third ventricle with the fourth ventricle, allowing cerebrospinal fluid to flow between these two areas.
Ventricles are openings in the brain that provide a pathway for cerebrospinal fluid is the cushiony fluid that protects the brain and spine from trauma.
The cerebral aqueduct drains cerebrospinal fluid from the third ventricle to the fourth ventricle where the third ventricle is a narrow, four-sided, irregularly shaped opening in the middle of the brain.
The fourth ventricle is a wide, flat open space located in the back bottom part of the brain.