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Overview of Major Brain Structures and Functions

  • The adult brain is divided into the cerebrum, diencephalon, cerebellum, and brainstem.
  • Lateral and midsagittal image descriptionviews of the brain show the anatomical boundaries of these major brain divisions.
An image showing the lateral view of the brain
An image showing the lateral and sagittal view of the brain
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  • Making up most (80-85%) of the brain are the right and left hemispheres of the image descriptioncerebrum.
An image showing the lateral and sagittal view of the brain
An image showing lateral view of the Right cerebral hemisphere of the and sagittal view of the Left cerebral hemisphere of the brain
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  • Beneath the convoluted surface of the cerebrum lies a thin layer of gray matter (cerebral cortex), which performs many higher level functions.
  • Sensations are imaged and interpreted, movements are planned, memories are stored and retrieved, and complex judgments are made.
  • Underneath the large cerebrum is the much smaller image descriptiondiencephalon. Most of this region consists of the right and left image descriptionthalamus.
An image showing the lateral and sagittal view of the brain
An image showing the Diencephalon labeled, lateral and sagittal view of the brain
An image showing the Thalamus and Diencephalon labeled, lateral and sagittal view of the brain
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  • Many neurons synapse here so that sensory and motor information can be correctly routed to the cerebrum for further processing.
  • Inferior to the thalami is the image descriptionhypothalamus.
An image showing the Thalamus and Diencephalon labeled, lateral and sagittal view of the brain
An image showing the Hypothalamus, Thalamus and Diencephalon labeled, lateral and sagittal view of the brain
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  • This area regulates several involuntary functions, such as water balance, appetite, and body temperature.
  • Additionally, the hypothalamus is involved in the sensation of primitive emotions and regulation of hormones released from the anterior image descriptionpituitary gland.
An image showing the Hypothalamus, Thalamus and Diencephalon labeled, lateral and sagittal view of the brain
An image showing the Pituitary gland, Hypothalamus, Thalamus and Diencephalon labeled, lateral and sagittal view of the brain
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  • Inferior to the cerebrum is the second largest division of the brain called the image descriptioncerebellum.
An image showing the lateral and sagittal view of the brain
An image showing the Cerebellum labeled, lateral and sagittal view of the brain
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  • Like the cerebrum, it is made up of two, highly convoluted hemispheres.
  • The cerebellum coordinates ongoing muscular movements and helps maintain proper posture, equilibrium, and muscle tone.
  • The fourth major division of the adult brain is called the image descriptionbrainstem (or brain stem), which lies anterior to the cerebellum and inferior to the diencephalon.
An image showing the lateral and sagittal view of the brain
An image showing the brainstem colored and labeled, lateral and sagittal view of the brain
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  • At its superior end is the image descriptionmidbrain(or mesencephalon).
An image showing the brainstem colored and labeled, lateral and sagittal view of the brain
An image showing the Midbrain labeled, lateral and sagittal view of the brain
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  • One of the functions of this area is to control reflex tracking movements of the head, neck, and eyes based on stimuli received from the eyes and ears.
  • Inferior to the mesencephalon is a knob-like image descriptionpons.
An image showing the Midbrain labeled, lateral and sagittal view of the brain
An image showing the Pons and Midbrain labeled, lateral and sagittal view of the brain
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  • Most of the pons consists of ascending and descending tracts of axons (white matter).
  • However, it also contains several small nuclei (= gray matter).
  • Some of these nuclei help the cerebrum communicate with the cerebellum (relay center), and others help regulate breathing movements.
  • The pons also give rise to several of the cranial nerves.
  • The inferior portion of the brainstem is called the image descriptionmedulla oblongata, and it spans the distance from the pons to the spinal cord.
An image showing the Pons and Midbrain labeled, lateral and sagittal view of the brain
An image showing the Medulla oblongata, Pons and Midbrain labeled, lateral and sagittal view of the brain
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  • Because of its location, much of the medulla oblongata is made up of the same nerve fiber tracts that run through the spinal cord.
  • Many of the sensory tract neurons synapse here so that information can be relayed to higher brain centers for processing.
  • Nuclei in the medulla oblongata are involved with five of the cranial nerves, and they also control many of body’s vital (heart rate, blood pressure, & breathing) and non-vital (sneezing & coughing) visceral activities.

Overview:

An image showing the Pituitary gland, Hypothalamus, Thalamus and Diencephalon numbered without answers, lateral and sagittal view of the brain
An image showing the Pituitary gland, Hypothalamus, Thalamus and Diencephalon numbered with answers below, lateral and sagittal view of the brain
An image showing the Cerebellum numbered without answers below, lateral and sagittal view of the brain
An image showing the Cerebellum numbered with answers below, lateral and sagittal view of the brain
An image showing the Medulla oblongata, Pons and Midbrain numbered without answers, lateral and sagittal view of the brain
An image showing the Medulla oblongata, Pons and Midbrain numbered with answers below, lateral and sagittal view of the brain
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