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Ch. 12 The Central Nervous System
All textbooksMarieb, Hoehn 7th EditionCh. 12 The Central Nervous SystemProblem 11
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Chapter 11, Problem 11

What constitutes the blood brain barrier?

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The blood-brain barrier (BBB) is a selective permeability barrier that separates the circulating blood from the brain and extracellular fluid in the central nervous system (CNS).
The BBB is primarily composed of endothelial cells that line the brain's capillaries. These cells are tightly joined together by tight junctions, which restrict the passage of substances.
Astrocytes, a type of glial cell, play a crucial role in the maintenance and function of the BBB. Their end-feet envelop the capillaries and provide biochemical support to the endothelial cells.
Pericytes, which are contractile cells, are embedded in the basement membrane of the capillaries and contribute to the regulation of blood flow and the integrity of the BBB.
The BBB allows the passage of essential nutrients and gases, such as glucose and oxygen, while blocking potentially harmful substances, including pathogens and toxins, from entering the brain.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Blood-Brain Barrier (BBB)

The blood-brain barrier is a selective permeability barrier that separates the circulating blood from the brain and extracellular fluid in the central nervous system. It is primarily formed by endothelial cells of brain capillaries, which are tightly joined to prevent the passage of potentially harmful substances while allowing essential nutrients to pass through.
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Endothelial Cells

Endothelial cells line the blood vessels and play a crucial role in the formation of the blood-brain barrier. In the brain, these cells are characterized by tight junctions that restrict the movement of solutes and maintain the unique environment necessary for proper neuronal function, thus protecting the brain from toxins and pathogens.
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Transport Mechanisms

Transport mechanisms are vital for the function of the blood-brain barrier, as they regulate the entry of substances into the brain. These include passive diffusion for small, lipophilic molecules, and active transport systems for essential nutrients like glucose and amino acids, ensuring that the brain receives necessary resources while remaining shielded from harmful agents.
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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
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Textbook Question
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.
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Textbook Question
List four ways in which the CNS is protected.
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Textbook Question
A patient has suffered a cerebral hemorrhage that has caused dysfunction of the precentral gyrus of his right cerebral cortex. As a result, a. he cannot voluntarily move his left arm or leg, b. he feels no sensation on the left side of his body, c. he feels no sensation on his right side.
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Textbook Question
A number of brain structures are listed below. If an area is primarily gray matter, write a in the answer blank; if mostly white matter, respond with b.  ________    (1) cerebral cortex  ________    (2) corpus callosum and corona radiata  ________    (3) red nucleus  ________    (4) medial and lateral nuclear groups  ________    (5) medial lemniscus  ________    (6) cranial nerve nuclei  ________    (7) spinothalamic tract  ________    (8) fornix  ________    (9) cingulate and precentral gyri
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Textbook Question
a. What is the advantage of having a cerebrum that is highly convoluted? b. What term is used to indicate its grooves? Its outward folds? c. Which groove divides the cerebrum into two hemispheres? d. What divides the parietal from the frontal lobe? The parietal from the temporal lobe?
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