Part 2 book “Human anatomy” has contents: Brain and cranial nerves, spinal cord and spinal nerves, pathways and integrative functions, autonomic nervous system, lymphatic system, respiratory system, digestive system, urinary system, reproductive system, blood, and other contents. | N E R V O U S Outline Brain Development and Tissue Organization Embryonic Development of the Brain Organization of Neural Tissue Areas in the Brain Support and Protection of the Brain Cranial Meninges Brain Ventricles Cerebrospinal Fluid Blood-Brain Barrier Cerebrum Cerebral Hemispheres Functional Areas of the Cerebrum Central White Matter Cerebral Nuclei Diencephalon Epithalamus Thalamus Hypothalamus Brainstem Midbrain Pons Medulla Oblongata Cerebellum Cerebellar Peduncles Limbic System Cranial Nerves MODULE 7: NERVOUS SYSTEM S Y S T E M 15 Brain and Cranial Nerves 436 Chapter Fifteen Brain and Cranial Nerves A bout 4 to 6 million years ago, when the earliest humans were evolving, brain size was a mere 440 cubic centimeters (cc), not much larger than that of a modern chimpanzee. As humans have evolved, brain size has increased steadily and reached an average volume of 1200 cc to 1500 cc and an average weight of to kilograms. In addition, the texture of the outer surface of the brain (its hemispheres) has changed. Our skull size limits the size of the brain, so the tissue forming the brain’s outer surface folded on itself so that more neurons could fit into the space within the skull. Although modern humans display variability in brain size, it isn’t the size of the brain that determines intelligence, but the number of active synapses among neurons. The brain is often compared to a computer because they both simultaneously receive and process enormous amounts of information, which they then organize, integrate, file, and store prior to making an appropriate output response. But in some ways this is a weak comparison, because no computer is capable of the multitude of continual adjustments that the brain’s neurons perform. The brain can control numerous activities s imultaneously,
