Textbook Question
Fiber tracts that allow neurons within the same cerebral hemisphere to communicate are:
a. Association fibers
b. Commissures
c. Projection fibers
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Ch. 12 The Central Nervous System
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091
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Table of contents
- Ch. 1 The Human Body: An Orientation24
- Ch. 2 Chemistry Comes Alive25
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System10
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton11
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System26
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System26
- Ch. 13 The Peripheral Nervous System and Reflex Activity28
- Ch. 14 The Autonomic Nervous System18
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart22
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses29
- Ch. 22 The Respiratory System20
- Ch. 23 The Digestive System30
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System25
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System23
Marieb, Hoehn7th EditionHuman Anatomy & PhysiologyISBN: 9780805359091Not the one you use?Change textbook
Chapter 12, Problem 7
A professor unexpectedly blew a loud horn in his anatomy and physiology class. The students looked up, startled. The reflexive movements of their eyes were mediated by the:
a. Cerebral cortex
b. Inferior olives
c. Raphe nuclei
d. Superior colliculi
e. Nucleus gracilis
Verified step by step guidance1
Step 1: Understand the question is asking about the neural structure responsible for reflexive eye movements in response to a sudden stimulus, such as a loud horn.
Step 2: Recall that reflexive eye movements are rapid, involuntary responses that help orient the eyes toward a stimulus, often mediated by midbrain structures.
Step 3: Review the functions of the listed options: the cerebral cortex is involved in voluntary movement and higher processing; inferior olives are related to motor coordination; raphe nuclei are involved in serotonin production and mood regulation; nucleus gracilis processes sensory information from the body.
Step 4: Identify that the superior colliculi, part of the midbrain tectum, play a key role in visual reflexes and orienting movements of the eyes and head toward stimuli.
Step 5: Conclude that the reflexive eye movements in response to the loud horn are mediated by the superior colliculi.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Reflexive Eye Movements
Reflexive eye movements are automatic responses to sudden stimuli, such as a loud noise or a bright light. These movements help orient the eyes toward the source of the stimulus without conscious effort, enabling quick attention shifts to potential threats or important events.
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Tendon Reflex
Superior Colliculi
The superior colliculi are paired structures in the midbrain involved in processing visual and auditory information to coordinate reflexive eye and head movements. They play a key role in directing gaze and attention toward sudden stimuli, making them essential for reflexive eye movements.
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03:39Superior and Inferior
Role of Other Brain Structures in Reflexes
While structures like the cerebral cortex, inferior olives, raphe nuclei, and nucleus gracilis have important functions, they are not primarily responsible for reflexive eye movements. The cerebral cortex manages voluntary actions, inferior olives assist motor learning, raphe nuclei regulate mood, and nucleus gracilis processes somatosensory information.
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Related Practice
Textbook Question
Choose the correct term from the key to respond to the statements describing various brain areas.
Key:
a. Cerebellum
b. Corpora quadrigemina
c. Corpus callosum
d. Striatum
e. Hypothalamus
f. Medulla
g. Midbrain
h. Pons
i. Thalamus
________ (1) basal nuclei involved in fine control of motor activities
________ (2) region where there is a crossover of fibers of descending pyramidal tracts
________ (3) control of temperature, autonomic nervous system reflexes, hunger, and water balance
________ (4) houses the substantia nigra and cerebral aqueduct
________ (5) relay stations for visual and auditory stimuli input; found in midbrain
________ (6) houses vital centers for control of the heart, respiration, and blood pressure
________ (7) brain area through which all the sensory input is relayed to get to the cerebral cortex
________ (8) brain area most concerned with equilibrium, body posture, and coordination of motor activity
Textbook Question
a. What is the function of the basal nuclei?
b. Which basal nuclei form the striatum?
c. Which arches over the diencephalon?
Textbook Question
What constitutes the blood brain barrier?
Textbook Question
List four ways in which the CNS is protected.
Textbook Question
Destruction of the ventral horn cells of the spinal cord results in loss of
a. Integrating impulses
b. Sensory impulses
c. Voluntary motor impulses
d. All of these
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