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Questions and Answers
Which of the following is a function of the muscular system?
Which of the following is a function of the muscular system?
What is the major source of movement of blood in the body?
What is the major source of movement of blood in the body?
Which type of muscle is responsible for locomotion and facial expressions?
Which type of muscle is responsible for locomotion and facial expressions?
Which property of muscle allows it to respond to a stimulus?
Which property of muscle allows it to respond to a stimulus?
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Which type of muscle tissue is composed of long, cylindrical, multinucleated fibers?
Which type of muscle tissue is composed of long, cylindrical, multinucleated fibers?
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Which connective tissue surrounds a whole muscle?
Which connective tissue surrounds a whole muscle?
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Which type of muscle tissue is striated?
Which type of muscle tissue is striated?
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What is the function of transverse (T) tubules in muscle cells?
What is the function of transverse (T) tubules in muscle cells?
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Which protein stabilizes the position of myosin and accounts for much of the elasticity and extensibility of myofibrils?
Which protein stabilizes the position of myosin and accounts for much of the elasticity and extensibility of myofibrils?
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What is the function of tropomyosin in muscle contraction?
What is the function of tropomyosin in muscle contraction?
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What is the region in the A band where actin and myosin do not overlap called?
What is the region in the A band where actin and myosin do not overlap called?
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What is the protein that links thin filaments to the sarcolemma?
What is the protein that links thin filaments to the sarcolemma?
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Which of the following best describes the resting membrane potential of a neuron?
Which of the following best describes the resting membrane potential of a neuron?
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What is the main driving force behind the establishment of the resting membrane potential?
What is the main driving force behind the establishment of the resting membrane potential?
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Which type of ion channels open and close in response to small voltage changes across the plasma membrane?
Which type of ion channels open and close in response to small voltage changes across the plasma membrane?
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What is the main difference between depolarization and repolarization during an action potential?
What is the main difference between depolarization and repolarization during an action potential?
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Which of the following is true about the neuromuscular junction?
Which of the following is true about the neuromuscular junction?
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What is the role of acetylcholinesterase in the synaptic cleft?
What is the role of acetylcholinesterase in the synaptic cleft?
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What happens when acetylcholine binds to ligand-gated Na+ channels on the postsynaptic membrane?
What happens when acetylcholine binds to ligand-gated Na+ channels on the postsynaptic membrane?
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What is the role of calcium ions in muscle relaxation?
What is the role of calcium ions in muscle relaxation?
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According to the text, what is the response of a muscle fiber to a sub-threshold stimulus?
According to the text, what is the response of a muscle fiber to a sub-threshold stimulus?
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According to the text, what determines the strength of a muscle contraction?
According to the text, what determines the strength of a muscle contraction?
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What is the term for the phenomenon where each subsequent contraction in a rested muscle is stronger than the previous one?
What is the term for the phenomenon where each subsequent contraction in a rested muscle is stronger than the previous one?
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What happens to muscle tension as the frequency of action potentials increases?
What happens to muscle tension as the frequency of action potentials increases?
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What is the term for the phenomenon where muscle fibers partially relax between contractions?
What is the term for the phenomenon where muscle fibers partially relax between contractions?
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What is the term for the phenomenon where there is no relaxation between muscle contractions?
What is the term for the phenomenon where there is no relaxation between muscle contractions?
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During the depolarization phase of the action potential, the membrane potential changes from approximately -85 mV to approximately +20 mV.
During the depolarization phase of the action potential, the membrane potential changes from approximately -85 mV to approximately +20 mV.
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During the repolarization phase of the action potential, the inside of the plasma membrane changes from approximately +20 mV back to -85 mV.
During the repolarization phase of the action potential, the inside of the plasma membrane changes from approximately +20 mV back to -85 mV.
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Action potentials cause calcium ions to be released from the sarcoplasmic reticulum into the muscle cell.
Action potentials cause calcium ions to be released from the sarcoplasmic reticulum into the muscle cell.
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The decrease in calcium ion levels in the muscle cell leads to muscle relaxation.
The decrease in calcium ion levels in the muscle cell leads to muscle relaxation.
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Study Notes
Muscular System
- The muscular system is responsible for movement of blood in the body
- Skeletal muscle is responsible for locomotion and facial expressions
Muscle Structure
- Skeletal muscle tissue is composed of long, cylindrical, multinucleated fibers
- Epimysium is the connective tissue that surrounds a whole muscle
Muscle Properties
- Irritability is the property of muscle that allows it to respond to a stimulus
- Titin protein stabilizes the position of myosin and accounts for much of the elasticity and extensibility of myofibrils
Muscle Contraction
- Transverse (T) tubules play a role in muscle cells
- Tropomyosin is involved in muscle contraction
- The H zone is the region in the A band where actin and myosin do not overlap
- Dystrophin is the protein that links thin filaments to the sarcolemma
Neuron Function
- The resting membrane potential of a neuron is typically around -70 mV
- The main driving force behind the establishment of the resting membrane potential is the concentration gradient of potassium and sodium ions
- Voltage-gated ion channels open and close in response to small voltage changes across the plasma membrane
- Depolarization is the decrease in membrane potential, while repolarization is the return to resting potential
Neuromuscular Junction
- The neuromuscular junction is the site where a neuron releases acetylcholine to stimulate muscle contraction
- Acetylcholinesterase breaks down acetylcholine in the synaptic cleft
- When acetylcholine binds to ligand-gated Na+ channels on the postsynaptic membrane, it causes muscle contraction
- Calcium ions play a role in muscle relaxation
Muscle Contraction and Relaxation
- A sub-threshold stimulus does not cause muscle contraction
- The strength of a muscle contraction is determined by the number of muscle fibers stimulated
- The phenomenon of muscle fibers partially relaxing between contractions is called relaxation
- The phenomenon of muscle fibers not relaxing between contractions is called tetanus
- As the frequency of action potentials increases, muscle tension increases
- The term for the phenomenon where each subsequent contraction in a rested muscle is stronger than the previous one is post-tetanic potentiation
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Description
Test your knowledge on the contraction and relaxation of skeletal muscle and the neuromuscular junction. Explore topics such as motor neurons, action potentials, synapses, and synaptic clefts.
