Chapter 44. Lower Brain Structures

Learning Objectives

brainstem
lowest portion of the brain, just above spinal cord; consists of the medulla, pons, midbrain, and reticular formation
brain
largest part of the central nervous system; consists of about 80 billion neurons organized into networks for processing sensory information, storing memories, and controlling behavior
midbrain
part of brainstem that contains processing centers to turn the eyes or the head toward sights and sounds
cerebellum
brain structure that coordinates body movement and balance; involved in simple forms of learning
pons
part of brainstem that relays messages between the cerebellum and the cerebral cortex to help coordinate body movements; plays a role in sleep
cerebral cortex
six thin layers of interconnected neurons that cover the outer surface of the brain and do most of the brain's processing
reticular formation
part of brainstem that filters incoming sensory stimuli and helps regulate arousal and alertness
consciousness
the experience of being aware of the external world
thalamus
brain structure that relays sensory messages to the cortex and movement messages to the cerebellum
medulla
part of brainstem that controls breathing, heartbeat, and other vital functions
Lower Brain Structures
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Learning Objectives:

Identify the major structures of the lower brain.

Describe the functions of the major lower brain structures.

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1. The brainstem and associated structures form the base of the brain. All communications between the cerebral cortex and the rest of the body pass through these structures.

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2. The brainstem itself consists of the medulla, pons, and midbrain, with the reticular formation running through the center of these structures and into the thalamus.

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3. The medulla regulates survival functions such as heart rate, blood pressure, and breathing. The pons has a role in sleep, and works with the cerebellum in coordinating body movements.

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4. The reticular formation regulates a person’s level of alertness, and filters incoming sensory information for danger signals. It arouses a sleeping brain to bring a person back to consciousness.

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5. The cerebellum is attached to the back of the brainstem. Its primary role is to coordinate complex movements such as walking or reaching, but it also processes some sensory information and handles simple forms of learning.

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6. The midbrain is the top portion of the brainstem, located above the pons. The midbrain contains several small processing centers that link vision and hearing with movements of the head and eyes.

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7. The thalamus sits on top the brainstem, like a cap. The thalamus is the main relay station between the senses and the areas of the cerebral cortex that process sensory information.

Practice: Exploring the Lower Brain

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Practice: Exploring the Lower Brain

Select each of the labels to see a brief description of the function of each brain structure.

Function of the selected brain structure:

Thalamus. Relays sensory messages to the cortex for processing

Cerebellum. Coordinates movement and balance, and simple forms of learning

Pons. Plays a role in sleep and works with the cerebellum in coordinating movements

Medulla. Controls breathing, heartbeat, and other vital functions

Reticular. Filters incoming stimuli and helps regulate arousal and alertness

Midbrain. Links vision and hearing with movements of the head and eyes

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Quiz 1

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Quiz 1

Drag each label to the appropriate brain structure. When all the labels have been placed, select the CHECK ANSWER button.

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Perhaps you should go back to review structures in the lower brain.
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Medulla
Pons
Reticular formation
Cerebellum
Midbrain
Thalamus

Quiz 2

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Quiz 2

Match the brain structures of the lower brain to their descriptions by dragging each colored circle to the appropriate gray circle. When all circles have been placed, select the CHECK ANSWER button.

Select the NEXT button and move to the Conclusion.
Perhaps you should go back to review functions of structures in the lower brain.
medulla
pons
reticular formation
cerebellum
midbrain
thalamus
plays a role in sleep and works with the cerebellum in coordinating movements
links vision and hearing with movements of the head and eyes
controls breathing, heartbeat, and other vital functions
filters incoming stimuli and helps regulate arousal and alertness
coordinates movement and balance, and simple forms of learning
relays sensory messages to the cortex for processing

Conclusion

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