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4.3: Structures of the brain

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    313381
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    Brain Structures

    The surface of the brain, known as the cerebral cortex, is very uneven, characterized by a distinctive pattern of folds or bumps, known as gyri (singular: gyrus), and grooves, known as sulci (singular: sulcus), shown in Figure \(\PageIndex{1}\). These gyri and sulci form important landmarks that allow us to separate the brain into functional centers. The most prominent sulcus, known as the longitudinal fissure, is the deep groove that separates the brain into two halves or hemispheres: the left hemisphere and the right hemisphere. [1]

    Definition: Sulci (Singular: sulcus)

    Pattern of grooves in the cerebral cortex

    Definition:Longitudinal Fissure

    The deep sulcus that separates the brain into two halves or hemispheres

    Definition: Gyri (singular: gyrus)

    Pattern of folds or bumps in the cerebral cortex

    Definition: Cerebral Cortex

    the outer surface of the brain

    The surface of the brain.
    Figure \(\PageIndex{1}\): The surface of the brain is covered with gyri and sulci. A deep sulcus is called a fissure, such as the longitudinal fissure that divides the brain into left and right hemispheres. ([1])

    The two hemispheres are connected by a thick band of neural fibers known as the corpus callosum, consisting of about 200 million axons. The corpus callosum allows the two hemispheres to communicate with each other and allows for information being processed on one side of the brain to be shared with the other side. [1]

    Definition: Corpus Callosum

    Thick band of neural fibers that connects the brain’s two hemispheres

    Definition: Axon

    Long connecting fibers that extend over long distances and make connections with other neurons, often at the dendrites

    The two hemispheres of the cerebral cortex are part of the forebrain (see Figure \(\PageIndex{2}\)), which is the largest part of the brain. The forebrain contains the cerebral cortex and a number of other structures that lie beneath the cortex (subcortical structures): the thalamus, the hypothalamus, the pituitary gland, and the limbic system. The cerebral cortex, which is the outer surface of the brain, is associated with higher-level processes such as consciousness, thought, emotion, reasoning, language, and memory. Each cerebral hemisphere can be subdivided into four lobes, each associated with different functions. [1]

    Definition:Thalamus

    Located within the forebrain, beneath the cerebral cortex, and functions as a sensory relay for the brain

    Definition: Limbic System

    Involved in processing both emotion and memory and is made up of a number of different structures, but three of the most important are the hippocampus, the amygdala, and the hypothalamus

    Definition:Hypothalamus

    Part of the limbic system and regulates a number of homeostatic processes, including the regulation of body temperature, appetite, and blood pressure

    Definition: Forebrain

    The largest part of the brain containing the cerebral cortex and a number of other structures that lie beneath the cortex

    the forebrain, midbrain, and hindbrain.
    Figure \(\PageIndex{2}\): The brain and its parts can be divided into three main categories. ([3])

    Attributions


    This page titled 4.3: Structures of the brain is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Todd LaMarr (ASCCC Open Educational Resources Initiative) .