Chapter 12: The Central Nervous System

                This week we’re discussing the central nervous system in more detail. The central nervous system is made up of the brain and spinal cord. A vocabulary word you may want to be familiar with is cephalization. This is the evolution of the brain and how the elaboration of the anterior portion of the central nervous system, it also increases in neurons in the head and the highest level of this is shown in the human brain.

                The brain is composed of wrinkled, pinkish gray matter. The adult brain structure is broken up into 3 surface structures, the forebrain, midbrain, and hindbrain. These structures are further broken down into smaller categories; this can get confusing to understand so I am going to try and break it down, also you can find a handy diagram on page 429 of the text book that gives you a good visual of the structures of the brain.

1.     1.  Prosencephalon (forebrain)

a.       Telencephalon- contains the cerebrum: cortex, white matter and basal nuclei (derived from the lateral ventricles)

b.      Diencephalon- contains the thalamus, hypothalamus, and epithalamus (derived from the third ventricle)

2.     2.  Mesencephalon (midbrain)

a.       Mesencephalon- contains the brain stem and the midbrain (derived from the cerebral aqueduct)

3.    3.   Rhombencephalon (hindbrain)

a.       Metencephalon- contains the brain stem and pons (derived from the fourth ventricle)

b.      Myelencephalon- contains the medulla oblongata (derived from the fourth ventricle)

The two cerebral hemispheres are the biggest structure of the brain and most likely what you think of when you think of the brain. The brain contains ridges which are referred to as the gyri. The cerebral hemispheres contain shallow grooves called sulci. Lastly, it contains contain deep grooves called fissures. The fissures divide the large regions of the brain. The sulci divide the hemispheres into five lobes; frontal, parietal, temporal, occipital, and insula.

The cerebral cortex is make of superficial gray matter and this portion of the brain accounts for 40% of the mass of the brain. The main function of the cortex is that is enables us to be aware of ourselves, sensations, to communicate, to remember, and also to initiates voluntary movements. There are three types of functional areas are: Motor areas (control voluntary movements), sensory areas (conscious awareness of sensation), and association area (integrates diverse information). You need to be able to identify these areas on the brain and on page 434 there is a diagram with these areas as well as other structures of the brain that you need to know.

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