Structures of the Brain Psy240

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The human brain has five divisions. They start forming in the vertebrae embryo as the tissue that eventually develops into the central nervous system. The first developments of the brain are three swellings that appear at the anterior end of a fluid filled tube. These swellings eventually become the forebrain, midbrain, and hindbrain. What happens is, the forebrain swelling grows into two different swellings and so does the hindbrain swelling. This is what makes up the five divisions of the brain. These divisions are known as the telencephalon, the diencephalon, the mesencephalon, the metencephalon, and the myelencephalon. The myelencephalon, also called the medulla, is the most posterior of the divisions of the brain. It is composed mainly of tracts carrying signals between the brain and the body. The myelencephalon is made up of about 100 tiny nuclei that occupy and central core of the brain stem. These nuclei are responsible for a number of functions including sleeping, attention, movement, the maintenance of muscle tone, and various cardiac, circulatory, and respiratory reflexes. Damage to this part of the brain is life-threatening. The metencephalon also houses many tracts that both ascend and descend as part of a reticular formation. These structures create a bulge called the pons. The pons is one major division of the metencephalon. The other is the cerebellum. This is the large convoluted structure on the brain stem. Damage to this part of the brain makes it impossible to control one’s movements and to adapt them to changing conditions. Like the metencephalon, the mesencephalon also has two divisions. They are the tectum and the tegmentum. The tectum is the dorsal surface of the midbrain. In mammals, it is composed of two pairs of bumps called the colliculi. The posterior part is called the inferior colliculi and has an auditory function. The anterior pair is called the superior colliculi and hasa visual function. The tegmentum is the part of the...
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