The Ventricular System and Production of Cerebrospinal Fluid
KEY CONCEPTS The central nervous system consists of the brain and spinal cord; it is covered with the meninges and floats in cerebrospinal fluid.
Development of the Central Nervous System
The Spinal Cord
KEY CONCEPTS The nervous system develops first as a tube, which thickens and forms pockets and folds as cells are produced. The tube becomes the ventricular system. The primary cause of the difference between the human brain and that of other primates is a slightly extended period of symmetrical and asymmetrical division of progenitor cells located in the ventricular zone. The forebrain, surrounding the lateral and third ventricles, consists of the telencephalon (cerebral cortex, limbic system, and basal ganglia) and diencephalon (thalamus and hypothalamus). The midbrain, which surrounds the cerebral aqueduct, consists of the tectum and tegmentum. The hindbrain, which surrounds the fourth ventricle, contains the cerebellum, the pons, and the medulla.
The Autonomic Nervous System
KEY CONCEPTS The spinal and cranial nerves connect the central nervous system with the rest of the body. The autonomic nervous system consists of two divisions: sympathetic and parasympathetic.