How do brain cells differ from other cells in the body?
The cells send signals to adjoining cells more quickly.
The cells function Independently from other cells in the region.
The cells do not store glucose as glycogen.
The cells are combined in concentric circles that increase with age.
The Correct Answer is C
Neurons, or brain cells, are highly specialized cells responsible for transmitting information throughout the nervous system. Unlike other cells in the body, neurons do not store glucose in the form of glycogen. This characteristic makes them heavily reliant on a continuous and stable supply of glucose from the bloodstream to meet their energy demands. Here's a detailed explanation:
The Role of Glucose in Neurons
- Energy Demand: Neurons have a high energy demand due to their role in maintaining electrical gradients, neurotransmitter synthesis, and signal transmission. The primary source of energy for neurons is glucose.
- Blood-Brain Barrier: Glucose is transported from the bloodstream to the brain through the blood-brain barrier, a selective barrier that regulates the passage of substances into the brain. Specialized glucose transporters, primarily GLUT1 and GLUT3, facilitate the uptake of glucose into neurons.
- Glycolysis and ATP Production: Once inside the neuron, glucose undergoes glycolysis, a metabolic pathway that breaks down glucose to produce ATP (adenosine triphosphate), the energy currency of the cell. The end product of glycolysis, pyruvate, enters the mitochondria where it is further oxidized in the Krebs cycle and oxidative phosphorylation to produce more ATP.
Lack of Glycogen Storage in Neurons
No Glycogen Reserves: Unlike liver and muscle cells, neurons do not have significant glycogen stores. Glycogen is a stored form of glucose that can be mobilized during periods of low blood glucose levels. Neurons lack this storage capacity, making them highly dependent on a continuous supply of glucose from the blood.
Importance of Continuous Blood Flow
Constant Supply Needed: Due to their inability to store glucose, neurons require a constant supply of glucose from the bloodstream. Any interruption in blood flow, such as during a stroke or hypoglycemia, can quickly lead to energy depletion and neuronal dysfunction or death.
Physiological Implications
Ischemia and Hypoglycemia: Conditions that disrupt the delivery of glucose to the brain, such as ischemia (reduced blood flow) or hypoglycemia (low blood glucose levels), can have severe effects on neuronal function and survival. This highlights the critical need for maintaining adequate cerebral blood flow and glucose levels.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is ["A","B","D"]
Explanation
Choice A reason:
Improvement in activities of daily living (ADLs) and displaying hopefulness in interactions with others are positive nonverbal cues indicating that therapy and medication are effective. These improvements suggest that Edward is regaining interest in daily activities and looking forward to the future.
Choice B reason:
Being less tearful and able to discuss openly the loss of his grandfather with friends and in group settings are signs that Edward is processing his grief and benefiting from therapy. Open communication about his loss indicates emotional progress and acceptance.
Choice C reason:
Continuing to isolate is not a positive nonverbal cue. Isolation suggests that Edward is still struggling with his depressive symptoms and not fully engaging with his support system. This behavior indicates that further intervention may be needed.
Choice D reason:
Smiling appropriately and interacting with peers are positive nonverbal cues that therapy and medication are working. These behaviors show that Edward is beginning to re-engage socially and experience moments of joy and connection.
Correct Answer is D
Explanation
Iron is a critical component of hemoglobin in red blood cells. An inadequate intake of iron can lead to iron deficiency anemia, which results in a decrease in the quantity of circulating red blood cells.
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