Textbook Question
Sympathetic preganglionic neurons synapse:
a. directly on target cells.
b. on skeletal muscle fibers.
c. on sympathetic chain or collateral ganglia.
d. on vagal ganglia.
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Ch. 14 The Autonomic Nervous System and Homeostasis
Amerman2nd EditionHuman Anatomy & PhysiologyISBN: 9780136873822
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Table of contents
- Ch. 1 Introduction to Anatomy and Physiology26
- Ch. 2 The Chemistry of Life38
- Ch. 3 The Cell55
- Ch. 4 Histology47
- Ch. 5 The Integumentary System30
- Ch. 6 Bones and Bone Tissue36
- Ch. 7 The Skeletal System40
- Ch. 8 Articulations19
- Ch. 9 The Muscular System36
- Ch. 10 Muscle Tissue and Physiology29
- Ch. 11 Introduction to the Nervous System and Nervous Tissue28
- Ch. 12 The Central Nervous System42
- Ch. 13 The Peripheral Nervous System41
- Ch. 14 The Autonomic Nervous System and Homeostasis31
- Ch. 15 The Special Senses39
- Ch. 16 The Endocrine System42
- Ch. 17 The Cardiovascular System I: The Heart30
- Ch. 18 The Cardiovascular System II: The Blood Vessels43
- Ch. 19 Blood32
- Ch. 20 The Lymphatic System and Immunity45
- Ch. 21 The Respiratory System27
- Ch. 22 The Digestive System27
- Ch. 23 Metabolism and Nutrition7
- Ch. 24 The Urinary System39
- Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis39
- Ch. 26 The Reproductive System10
- Ch. 27 Development and Heredity5
Chapter 14, Problem L2.3
The drug neostigmine blocks the activity of the enzyme acetylcholinesterase in the synaptic cleft. Predict the effects of this drug.
Verified step by step guidance1
Understand the role of acetylcholinesterase: Acetylcholinesterase is an enzyme located in the synaptic cleft that breaks down the neurotransmitter acetylcholine into acetate and choline, terminating its action at the synapse.
Recognize the effect of blocking acetylcholinesterase: If neostigmine inhibits acetylcholinesterase, acetylcholine will not be broken down as efficiently, leading to an accumulation of acetylcholine in the synaptic cleft.
Predict the physiological outcome: The increased concentration of acetylcholine will result in prolonged stimulation of acetylcholine receptors on the postsynaptic membrane, enhancing cholinergic signaling.
Consider the potential effects on the body: Prolonged stimulation of acetylcholine receptors can lead to increased muscle contraction, improved transmission at neuromuscular junctions, and potentially overstimulation of parasympathetic nervous system functions (e.g., increased salivation, slowed heart rate).
Relate to clinical applications: Neostigmine is often used to treat conditions like myasthenia gravis, where it helps improve muscle strength by enhancing neuromuscular transmission, or to reverse the effects of muscle relaxants used during surgery.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acetylcholinesterase Function
Acetylcholinesterase is an enzyme that breaks down the neurotransmitter acetylcholine in the synaptic cleft, which is the space between nerve cells. By hydrolyzing acetylcholine, it terminates the signal transmission between neurons and muscle cells, allowing for muscle relaxation and preventing continuous stimulation.
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Functional Groups
Neostigmine Mechanism of Action
Neostigmine is a reversible inhibitor of acetylcholinesterase, meaning it binds to the enzyme and prevents it from breaking down acetylcholine. This leads to an accumulation of acetylcholine in the synaptic cleft, resulting in prolonged stimulation of the postsynaptic receptors, which can enhance muscle contraction and improve neuromuscular transmission.
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Clinical Implications of Neostigmine
Neostigmine is commonly used in the treatment of myasthenia gravis, a condition characterized by weakness in the skeletal muscles. By increasing acetylcholine levels, neostigmine helps improve muscle strength and function. However, excessive inhibition of acetylcholinesterase can lead to cholinergic crisis, characterized by muscle twitching, respiratory distress, and other symptoms due to overstimulation of the neuromuscular junction.
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07:53Resting Membrane Potential
Related Practice
Textbook Question
Describe all the changes initiated by the parasympathetic nervous system that will take place when you finish the race. How will these changes maintain homeostasis?
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Textbook Question
Common findings in heart failure are fluid retention by the kidneys and stimulation of the heart by the sympathetic nervous system. How would both of these findings help the body to compensate for the failing heart?
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Textbook Question
You are running a race to the top of a mountain. Explain all the changes your sympathetic nervous system will initiate to maintain homeostasis as you run the race.
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Textbook Question
Using 20 or fewer words, define each of the following terms in your own words.
b. Parasympathetic nervous system
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Textbook Question
Using 20 or fewer words, define each of the following terms in your own words.
a. Sympathetic nervous system
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