Notes Ch. 11B Nervous System II Anatomy and Physiology

Brain The brain has neural centers that are responsible for sensations and perceptions. It commands the skeletal muscles and carries on higher mental function, like memory and reasoning. The brain is also responsible for personality.

Brain Development The basic structure of the brain shows the way it forms during early development. It begins as the neural tube that becomes the central nervous system. The part that becomes the brain has 3 major cavities - the forebrain, midbrain, and hindbrain.

The forebrain will divide into anterior and posterior parts, the hindbrain divides into 2 parts. Eventually the midbrain, pons, and medulla oblongata make the brainstem.

Structure of the Cerebrum The cerebrum is the largest part of the brain. It has 2 large cerebral hemispheres which are mirror images of each other. There is also the corpus callosum which is a broad, flat bundle of axons that connects the cerebral hemispheres.

There are many ridges called gyri that separated by grooves on the cerebrum surface. A shallow to somewhat deep groove is called a sulcus. A very deep groove is called a fissure. There is a longitudinal fissure that separates the right and left cerebral hemispheres. A transverse fissure separates the cerebrum from the cerebellum.

There are 5 lobes of the cerebral hemispheres: The frontal lobe - the anterior part of each cerebral hemisphere. The parietal lobe is posterior (behind) the frontal lobe. The temporal lobe is inferior to the frontal and parietal lobes. The occipital lobe is posterior to each cerebral hemisphere. 5. Insula - the lobe deep within the lateral sulcus.

The cerebral cortex is a thin layer of gray matter The cerebral cortex is a thin layer of gray matter. It is the outer part of the cerebrum. It contains 75% of all the neuron cell bodies in the nervous system. Under the cerebral cortex is white matter that is most of the cerebrum. Some of the neuron cell bodies will pass from one cerebral hemisphere to the other.