Tissues And Functions Of The Muscular System
What tissues are found in the muscular system? What are the functions of the different tissues and parts of the system? These are some of the questions that the tissues and functions of the muscular system will help you answer.
- 1.
Most muscles cross at least one
- A.
Tendon.
- B.
Joint.
- C.
Bone.
- D.
Ligament.
- E.
Body plane.
Correct Answer
B. Joint.Explanation
Most muscles in the human body cross at least one joint. A joint is a point where two or more bones meet, allowing movement and flexibility. Muscles attach to bones via tendons, which are strong, fibrous tissues that connect muscle to bone. When a muscle contracts, it pulls on the tendon, causing movement at the joint. Therefore, it is accurate to say that most muscles cross at least one joint in order to facilitate movement.Rate this question:
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- 2.
The attachment of a muscle’s tendon to the stationary bone is called the ___; the attachment of the muscle's other tendon to the movable bone is called ___.
- A.
Origin, action
- B.
Insertion, action
- C.
Origin, insertion
- D.
Insertion, origin
Correct Answer
C. Origin, insertionExplanation
The attachment of a muscle's tendon to the stationary bone is called the origin, while the attachment of the muscle's other tendon to the movable bone is called insertion.Rate this question:
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- 3.
A lever is acted on at two different points by two different forces which are
- A.
Fulcrum and resistance.
- B.
Leverage and load.
- C.
Lever and resistance.
- D.
Effort and load.
- E.
Lever and effort.
Correct Answer
D. Effort and load.Explanation
In a lever system, the effort is the force applied to move the lever, while the load is the resistance or weight being lifted or moved. The fulcrum is the pivot point of the lever, and the resistance refers to the force opposing the effort. Therefore, the correct answer is "effort and load" as they accurately represent the forces acting on the lever.Rate this question:
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- 4.
Motion will occur in a muscle when the ___ supplied exceeds the ___.
- A.
Effort, load
- B.
Resistance, lever
- C.
Load, effort
- D.
Load, resistance
- E.
Lever, effort
Correct Answer
A. Effort, loadExplanation
Motion will occur in a muscle when the effort supplied exceeds the load. In other words, when the force applied by the muscle is greater than the resistance it is trying to move, motion will occur.Rate this question:
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- 5.
Which of the following is not a fascicle arrangement?
- A.
Pennate
- B.
Triangular
- C.
Oval
- D.
Parallel
- E.
Fusiform
Correct Answer
C. OvalExplanation
The fascicle arrangement refers to the pattern in which muscle fibers are organized within a muscle. In a pennate arrangement, the muscle fibers are obliquely attached to a central tendon, giving a feather-like appearance. Triangular, parallel, and fusiform arrangements are all types of fascicle arrangements commonly found in muscles. However, an oval arrangement is not a recognized fascicle arrangement. This suggests that oval is the correct answer as it does not fit the criteria of a fascicle arrangement.Rate this question:
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- 6.
This type of fascicle arrangement has the fascicles spread over a broad area and converges at a thick central tendon.
- A.
Triangular
- B.
Pennate
- C.
Circular
- D.
Fusiform
- E.
Multipennate
Correct Answer
A. TriangularExplanation
A triangular fascicle arrangement is characterized by fascicles that are spread over a broad area and converge at a thick central tendon. This arrangement resembles the shape of a triangle, with the fascicles radiating outwards from the central tendon.Rate this question:
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- 7.
What is another name for a prime mover?
- A.
Antagonist
- B.
Agonist
- C.
Synergist
- D.
Asynergist
- E.
Fixator
Correct Answer
B. AgonistExplanation
An agonist is a muscle that is primarily responsible for producing a specific movement or action. It is the main muscle involved in generating force and initiating a movement. Therefore, it can be considered as the prime mover. The other options listed are not synonyms for a prime mover and do not accurately describe the function of an agonist muscle.Rate this question:
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- 8.
This type of muscle works by stabilizing the origin of a prime mover so that it can act more efficiently
- A.
Synergist
- B.
Agonist
- C.
Antagonist
- D.
Fixator
- E.
Secondary mover
Correct Answer
D. FixatorExplanation
A fixator muscle is a type of muscle that stabilizes the origin of a prime mover. It helps to keep the origin of the prime mover steady, allowing it to act more efficiently. This means that the fixator muscle supports and reinforces the action of the prime mover, enabling it to perform its function effectively.Rate this question:
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- 9.
Which of the following is not one of the descriptive ways to name a muscle?
- A.
Size
- B.
Shape
- C.
Number of origins
- D.
Sites of origins
- E.
Number of cells
Correct Answer
E. Number of cellsExplanation
The number of cells is not one of the descriptive ways to name a muscle. Descriptive ways to name a muscle typically include characteristics such as size, shape, number of origins, and sites of origins. The number of cells is not a commonly used characteristic for naming muscles, as it does not provide specific information about the muscle's physical attributes or function.Rate this question:
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- 10.
Describe the characteristics used to name skeletal muscle
- A.
Contents
- B.
Direction
- C.
Size
- D.
Weight
- E.
Shape
- F.
Action
- G.
Number of tendons
- H.
Number of origins
- I.
Location
- J.
Smell
- K.
Origin and Insertion
- L.
Mass
- M.
Volume
Correct Answer(s)
B. Direction
C. Size
E. Shape
F. Action
H. Number of origins
I. Location
K. Origin and InsertionExplanation
The characteristics used to name skeletal muscles include direction, size, shape, action, number of origins, location, and origin and insertion. Direction refers to the orientation of the muscle fibers, such as transverse or oblique. Size refers to the relative dimensions of the muscle, such as long or short. Shape describes the overall form of the muscle, such as triangular or fusiform. Action refers to the movement produced by the muscle, such as flexion or extension. Number of origins refers to the number of attachment points of the muscle. Location indicates the specific region or body part where the muscle is located. Origin and insertion refer to the points where the muscle originates and inserts on bones or other structures.Rate this question:
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- 11.
The different types of muscle tissue differ from each other by:
- A.
Microscopic anatomy
- B.
Location
- C.
Type of control
- D.
Both microscopic anatomy and location
- E.
All of these choices
Correct Answer
E. All of these choicesExplanation
The different types of muscle tissue differ from each other by their microscopic anatomy, location, and type of control. Microscopic anatomy refers to the structural characteristics of the muscle tissue, such as the arrangement of muscle fibers and the presence of specific proteins. Location refers to where the muscle tissue is found in the body, such as skeletal muscles attached to bones or smooth muscles in the walls of organs. Type of control refers to whether the muscle tissue is under voluntary control (skeletal muscles) or involuntary control (smooth and cardiac muscles). Therefore, all of these choices contribute to the differences between the types of muscle tissue.Rate this question:
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- 12.
Which of the following is NOT a major function of muscle tissue?
- A.
Moving blood throughout the body
- B.
Generating heat through contractions
- C.
Stabilizing joints
- D.
Promoting movement of body structures
- E.
Storing energy
Correct Answer
E. Storing energyExplanation
Muscle tissue is responsible for various functions in the body, including moving blood throughout the body, generating heat through contractions, stabilizing joints, and promoting movement of body structures. However, storing energy is not a major function of muscle tissue. Energy storage is primarily carried out by adipose tissue, which is specialized for storing excess energy in the form of fat.Rate this question:
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- 13.
This is the property of muscle that gives it the ability to stretch without damage.
- A.
Electrical excitability
- B.
Contractility
- C.
Extensibility
- D.
Elasticity
- E.
Thermogenicity
Correct Answer
C. ExtensibilityExplanation
Extensibility is the property of muscle that allows it to stretch without causing damage. This means that muscles can be elongated or stretched beyond their normal resting length without tearing or breaking. This is crucial for muscle function as it allows for a greater range of motion and flexibility. It also enables muscles to adapt and grow in response to exercise and physical activity.Rate this question:
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- 14.
In an isometric contraction the muscle develops tension but does not
- A.
Lengthen
- B.
Widen.
- C.
Shorten
- D.
Conduct electrical current.
- E.
Produce force.
Correct Answer
C. ShortenExplanation
In an isometric contraction, the muscle develops tension but does not lengthen. This means that the muscle remains at a constant length while still generating force. The contraction is characterized by the muscle fibers pulling on each other without any visible movement or change in length. Therefore, the correct answer is "shorten."Rate this question:
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- 15.
Which one of these statements is FALSE?
- A.
The force of a muscle contraction increases as more motor units are activated.
- B.
Concentric isotonic contractions occur when the load equals or exceeds the tension produced in the muscle
- C.
Recruitment is the process in which the number of motor units stimulated during a contraction is increased.
- D.
When a second stimulus occurs before the muscle has relaxed, wave summation occurs and the second contraction generates more force than the first contraction.
- E.
A motor unit is a motor neuron and all of the myofibers it innervates
Correct Answer
B. Concentric isotonic contractions occur when the load equals or exceeds the tension produced in the muscleExplanation
The statement that is FALSE is "Concentric isotonic contractions occur when the load equals or exceeds the tension produced in the muscle." In reality, concentric isotonic contractions occur when the tension produced in the muscle exceeds the load. In this type of contraction, the muscle shortens while generating force, such as when lifting a weight.Rate this question:
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- 16.
Which of the following statements is TRUE regarding Fast Glycolytic fibers found in skeletal muscle
- A.
They are small in diameter
- B.
They are adapted for intense bursts of anaerobically fueled movement
- C.
They have abundant mitochondria.
- D.
They contract slowly, but are resistant to fatigue.
- E.
They contain vast quantities of myoglobin.
Correct Answer
B. They are adapted for intense bursts of anaerobically fueled movementExplanation
Fast Glycolytic fibers found in skeletal muscle are adapted for intense bursts of anaerobically fueled movement. This means that they are designed to produce quick and powerful contractions without the need for oxygen. These fibers rely on the breakdown of glucose through glycolysis to generate energy rapidly. This allows for short bursts of high-intensity activity, such as sprinting or weightlifting.Rate this question:
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- 17.
Which of the following statements is TRUE regarding Slow Oxidative fibers found in skeletal muscle?
- A.
They are large in diameter
- B.
They are adapted for intense bursts of anaerobically fueled movement
- C.
They contain vast stores of glycogen.
- D.
They contract slowly, but are resistant to fatigue.
- E.
They are the last fibers to be recruited in situations where maximal force is required.
Correct Answer
D. They contract slowly, but are resistant to fatigue.Explanation
Slow oxidative fibers found in skeletal muscle contract slowly, but are resistant to fatigue. This means that they are designed for endurance activities that require prolonged contraction without tiring easily. These fibers are smaller in diameter compared to fast-twitch fibers, which are adapted for intense bursts of anaerobically fueled movement. Slow oxidative fibers also have a high capacity for oxidative metabolism, enabling them to generate ATP aerobically and sustain contractions for longer periods. They do not contain vast stores of glycogen like fast-twitch fibers, which rely more on anaerobic metabolism. Additionally, slow oxidative fibers are typically recruited early on during activities that require low to moderate force.Rate this question:
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- 18.
Calcium ions bind to the ___ molecule in skeletal muscle cells.
- A.
Actin
- B.
Troponin
- C.
Tropomyosin
- D.
Myosin
- E.
Titin
Correct Answer
B. TroponinExplanation
Calcium ions play a crucial role in muscle contraction. In skeletal muscle cells, calcium ions bind to the troponin molecule. Troponin is a regulatory protein that is part of the thin filament in muscle cells. When calcium ions bind to troponin, it causes a conformational change that allows the myosin heads to interact with actin, leading to muscle contraction. Therefore, troponin is directly involved in the regulation of muscle contraction in skeletal muscle cells.Rate this question:
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- 19.
This is a band of connective tissue that surrounds whole muscles
- A.
Tendon
- B.
Ligament
- C.
Endomysium
- D.
Epimysium
- E.
Perimysium
Correct Answer
D. EpimysiumExplanation
The epimysium is a band of connective tissue that surrounds whole muscles. It provides support and protection to the muscle fibers and helps to maintain the shape and integrity of the muscle. It is the outermost layer of connective tissue in the muscle and is responsible for connecting the muscle to the surrounding structures.Rate this question:
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- 20.
When connective tissue extends as a broad flat layer, the tendon is referred to as
- A.
Perimysium.
- B.
Deep fascia.
- C.
Fascicle.
- D.
Aponeurosis
- E.
Endomysium
Correct Answer
D. AponeurosisExplanation
An aponeurosis is a broad, flat tendon-like structure that connects muscles to other structures, such as bones or other muscles. It is formed when connective tissue extends as a broad flat layer. This allows for a wide distribution of forces and helps to provide strength and stability to the area. Therefore, the correct answer is aponeurosis.Rate this question:
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- 21.
For every nerve that penetrates a skeletal muscle, there are in general how many arteries and veins?
- A.
One artery and one or two veins
- B.
Two arteries and two veins
- C.
Three arteries and two veins
- D.
One artery and three veins
- E.
One artery and a varied amount of veins
Correct Answer
A. One artery and one or two veinsExplanation
For every nerve that penetrates a skeletal muscle, there is generally one artery and one or two veins. This means that the muscle receives a supply of oxygenated blood through the artery and the deoxygenated blood is drained away through the veins. The number of veins can vary, but there is always at least one artery and one vein present.Rate this question:
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- 22.
Axon terminal clusters at the ends of motor neurons that are considered part of the neuromuscular junction are referred to as
- A.
Myelin bulbs
- B.
Neuromuscular bulbs
- C.
Synaptic end bulbs
- D.
Axon collateral bulb
- E.
Tubule bulb
Correct Answer
C. Synaptic end bulbsExplanation
Axon terminal clusters at the ends of motor neurons are referred to as synaptic end bulbs. These bulbs play a crucial role in the transmission of signals from the motor neurons to the muscles at the neuromuscular junction. They contain neurotransmitters that are released into the synaptic cleft, allowing the signal to be transmitted to the muscle fibers and causing them to contract.Rate this question:
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- 23.
After the fusion of myoblasts, the muscle fiber loses its ability to do what?
- A.
Grow
- B.
Lengthen
- C.
Contract
- D.
Go through mitosis
- E.
All of these choices
Correct Answer
D. Go through mitosisExplanation
After the fusion of myoblasts, the muscle fiber loses its ability to go through mitosis. Myoblasts are precursor cells that fuse together to form muscle fibers. Once fusion occurs, the muscle fiber becomes multinucleated and cannot divide further through mitosis. This is because the fusion process combines the nuclei of the myoblasts, resulting in a single nucleus in the muscle fiber. Therefore, the muscle fiber cannot undergo cell division and mitosis.Rate this question:
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- 24.
Which of the following represents the sequence that muscle action potentials must go through to excite a muscle cell?
- A.
Sarcolemma, axon of neuron, T tubules
- B.
T tubules, sarcolemma, myofilament
- C.
Muscle fiber, axon of neuron, myofibrils
- D.
Axon of neuron, sarcolemma, T tubules
- E.
Myofibrils, myofilaments, mitochondria
Correct Answer
D. Axon of neuron, sarcolemma, T tubules -
- 25.
These are the contractile organelles of the muscle fiber.
- A.
Myofibrils
- B.
Myoglobin
- C.
Mitochondria
- D.
Z disc
- E.
M line
Correct Answer
A. MyofibrilsExplanation
Myofibrils are the contractile organelles of the muscle fiber. They are responsible for the contraction and relaxation of muscles. Made up of repeating units called sarcomeres, myofibrils contain thick and thin filaments that slide past each other during muscle contraction, resulting in muscle movement. These structures play a crucial role in generating force and enabling muscle contraction. Myofibrils are essential for muscle function and are therefore the correct answer in this context.Rate this question:
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- 26.
This part of the skeletal muscle cell releases calcium when stimulated by the T tubules
- A.
Myofibrils
- B.
Sarcoplasm
- C.
Terminal cisterns of sarcoplasmic reticulum
- D.
Sarcomeres
- E.
Sarcolemma
Correct Answer
C. Terminal cisterns of sarcoplasmic reticulumExplanation
The terminal cisterns of the sarcoplasmic reticulum are responsible for releasing calcium when stimulated by the T tubules. Calcium is a crucial ion in muscle contraction, as it binds to the protein troponin, allowing the myosin heads to interact with actin and initiate the sliding of the sarcomeres, which ultimately leads to muscle contraction. The terminal cisterns are specialized regions of the sarcoplasmic reticulum that are located near the T tubules, allowing for efficient communication and coordination between the two structures during muscle contraction.Rate this question:
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- 27.
The sarcoplasmic reticulum is used for storing
- A.
Oxygen
- B.
ATP
- C.
Myoglobin
- D.
Na+
- E.
Ca2+
Correct Answer
E. Ca2+Explanation
The sarcoplasmic reticulum is a specialized organelle found in muscle cells that is responsible for storing and releasing calcium ions (Ca2+). Calcium ions play a crucial role in muscle contraction by binding to proteins within the muscle fibers and initiating the sliding of the actin and myosin filaments. This allows for the generation of force and movement. Therefore, the sarcoplasmic reticulum is used for storing Ca2+ ions, which are essential for muscle function.Rate this question:
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- 28.
Which of the following contains thin filaments?
- A.
I band
- B.
A band
- C.
H zone
- D.
Both I band and A band
- E.
All of these choices
Correct Answer
D. Both I band and A bandExplanation
Both the I band and A band contain thin filaments. The I band is a region of the sarcomere where only thin filaments are present. It is located between two A bands and represents the distance between two adjacent sarcomeres. The A band, on the other hand, contains both thin and thick filaments. It is the region where thick filaments overlap with thin filaments, giving it a darker appearance. Therefore, the correct answer is both I band and A band.Rate this question:
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- 29.
Which of the following contains thick filaments?
- A.
Zone of overlap
- B.
A band
- C.
H zone
- D.
Both a band and h zone
- E.
All of these choices
Correct Answer
E. All of these choicesExplanation
The correct answer is "all of these choices." This is because all of the listed options contain thick filaments. The zone of overlap is the region where thick and thin filaments overlap, the A band is the region where thick filaments are located, and the H zone is the region within the A band where only thick filaments are present. Therefore, all of these choices contain thick filaments.Rate this question:
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- 30.
Myofibrils contain
- A.
Contractile proteins
- B.
Regulatory proteins
- C.
Structural proteins
- D.
All of these choices
- E.
None of these choices
Correct Answer
D. All of these choicesExplanation
Myofibrils contain all of these choices: contractile proteins, regulatory proteins, and structural proteins. Contractile proteins, such as actin and myosin, are responsible for muscle contraction. Regulatory proteins, such as tropomyosin and troponin, regulate the interaction between actin and myosin. Structural proteins, such as titin and dystrophin, provide support and stability to the myofibrils. Therefore, all three types of proteins are present in myofibrils.Rate this question:
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- 31.
Which of the following functions as a motor protein in all three types of muscle tissue?
- A.
Actin
- B.
Myosin
- C.
Troponin
- D.
Titin
- E.
Tropomyosin
Correct Answer
B. MyosinExplanation
Myosin is the correct answer because it is a motor protein that is involved in muscle contraction in all three types of muscle tissue, namely skeletal, cardiac, and smooth muscle. Myosin interacts with actin filaments to generate the force required for muscle contraction. It acts as a molecular motor by using ATP to undergo a conformational change, which allows it to move along the actin filaments and generate the sliding motion necessary for muscle contraction.Rate this question:
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- 32.
What regulatory proteins can be found associated with an actin molecule?
- A.
Troponin and titin
- B.
Tropomyosin and troponin
- C.
Myosin and titin
- D.
Titin and tropomyosin
- E.
Titin and calsequestrin
Correct Answer
B. Tropomyosin and troponinExplanation
Tropomyosin and troponin are regulatory proteins that can be found associated with an actin molecule. Tropomyosin is a long, filamentous protein that wraps around the actin filament, regulating access to the myosin binding sites on actin. Troponin is a complex of three subunits that binds to tropomyosin and actin. It plays a crucial role in regulating muscle contraction by controlling the position of tropomyosin on the actin filament. Together, tropomyosin and troponin work to regulate the interaction between actin and myosin during muscle contraction.Rate this question:
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- 33.
Titin is found in a sarcomere
- A.
In the A band only
- B.
In the H zone only
- C.
From the zone of overlap to the Z disc
- D.
From the M line to the Z disc
- E.
In the I band only.
Correct Answer
D. From the M line to the Z discExplanation
Titin is a protein that is found in the sarcomere, which is the basic unit of a muscle fiber. It spans from the M line to the Z disc within the sarcomere. The M line is located in the center of the sarcomere, while the Z disc is found at the ends of the sarcomere. Therefore, the correct answer is that titin is found from the M line to the Z disc.Rate this question:
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- 34.
Which of the following is used to reinforce the sarcolemma?
- A.
Troponin
- B.
Tropomyosin
- C.
Myosin
- D.
Actin
- E.
Dystrophin
Correct Answer
E. DystropHinExplanation
Dystrophin is a protein that is used to reinforce the sarcolemma, which is the cell membrane of muscle fibers. It helps to maintain the structural integrity of the sarcolemma and prevent damage during muscle contractions. Dystrophin is particularly important in skeletal muscle, and its absence or dysfunction can lead to muscular dystrophy, a group of genetic disorders characterized by muscle weakness and degeneration.Rate this question:
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- 35.
In the sliding filament mechanism, the thin filament is being pulled towards the
- A.
Z disc.
- B.
H zone.
- C.
M line.
- D.
A band.
- E.
I band.
Correct Answer
C. M line.Explanation
In the sliding filament mechanism, the thin filament is being pulled towards the M line. The M line is located in the center of the sarcomere and serves as the attachment point for the thick filaments. As the thick filaments slide past the thin filaments during muscle contraction, the thin filaments are pulled towards the M line. This movement causes the sarcomere to shorten, resulting in muscle contraction. Therefore, the correct answer is M line.Rate this question:
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- 36.
The sarcoplasmic reticulum releases calcium ions into the cytosol
- A.
At the beginning of a contraction
- B.
Throughout the entire contraction.
- C.
During the midpoint only of the contraction.
- D.
After the contraction ends.
- E.
All of these choices.
Correct Answer
A. At the beginning of a contractionExplanation
The sarcoplasmic reticulum is responsible for storing and releasing calcium ions, which are crucial for muscle contractions. When a muscle is stimulated to contract, the sarcoplasmic reticulum releases calcium ions into the cytosol, which then bind to specific proteins called troponin. This binding allows the muscle fibers to slide past each other, resulting in muscle contraction. Therefore, the correct answer is that the sarcoplasmic reticulum releases calcium ions at the beginning of a contraction.Rate this question:
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- 37.
What energizes the myosin head?
- A.
The actin filaments
- B.
Calcium ions
- C.
Potassium ions
- D.
Hydrolysis of ATP
- E.
Phosphorylation of ADP
Correct Answer
D. Hydrolysis of ATPExplanation
The myosin head is energized by the hydrolysis of ATP. During muscle contraction, ATP is broken down into ADP and inorganic phosphate, releasing energy that is used to power the movement of the myosin head. This energy allows the myosin head to bind to actin filaments and undergo a conformational change, resulting in muscle contraction. Calcium ions are involved in the regulation of muscle contraction, but they do not directly energize the myosin head. Potassium ions and phosphorylation of ADP are not directly involved in the energization of the myosin head.Rate this question:
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- 38.
What is needed for the contraction cycle to continue?
- A.
ATP and Acetylcholine (ACh)
- B.
Calcium ions and ATP
- C.
ACh and potassium
- D.
Water and ATP
- E.
Calcium ACh
Correct Answer
B. Calcium ions and ATPExplanation
The contraction cycle in muscle cells requires the presence of calcium ions and ATP. Calcium ions are necessary for the binding of myosin and actin, which initiates muscle contraction. ATP is needed for the detachment of myosin from actin and the re-energizing of the myosin heads, allowing for repeated muscle contractions. Therefore, both calcium ions and ATP are essential for the contraction cycle to continue.Rate this question:
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- 39.
This phase is described as a muscle action potential propagating along the sarcolemma and into the T tubules.
- A.
Contraction
- B.
Relaxation
- C.
Excitation
- D.
Release channel
- E.
ATP hydrolysis
Correct Answer
C. ExcitationExplanation
Excitation refers to the phase where a muscle action potential propagates along the sarcolemma (cell membrane of a muscle fiber) and into the T tubules (invaginations of the sarcolemma). This phase is crucial for initiating muscle contraction. During excitation, the action potential triggers the release of calcium ions from the sarcoplasmic reticulum, which then binds to troponin and allows for the interaction between actin and myosin filaments, leading to muscle contraction.Rate this question:
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- 40.
The signal to excite a muscle cell must cross the neuromuscular junction by the diffusion of acetylcholine across the
- A.
Motor neuron axon.
- B.
Synaptic cleft
- C.
Sarcolemma
- D.
Synaptic vesicles.
- E.
Myofibril
Correct Answer
B. Synaptic cleftExplanation
The signal to excite a muscle cell must cross the synaptic cleft. The synaptic cleft is the small gap between the motor neuron axon and the muscle cell, where the neuromuscular junction is located. Acetylcholine, a neurotransmitter, is released from the synaptic vesicles in the motor neuron axon and diffuses across the synaptic cleft. It then binds to receptors on the sarcolemma of the muscle cell, initiating a series of events that lead to muscle contraction. Therefore, the diffusion of acetylcholine across the synaptic cleft is necessary for the signal to excite a muscle cell.Rate this question:
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- 41.
How many molecules of acetylcholine need to bind to open the ion channel of the ACh receptor?
- A.
34
- B.
5
- C.
10
- D.
An unknown amount
- E.
2
Correct Answer
E. 2Explanation
The correct answer is 2 because acetylcholine, a neurotransmitter, needs to bind with two molecules to open the ion channel of the ACh receptor. This binding triggers a conformational change in the receptor, allowing ions to flow through the channel and propagate the nerve signal.Rate this question:
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- 42.
How do muscles produce ATP?
- A.
Creatine phosphate
- B.
Anaerobic cellular respiration
- C.
Aerobic cellular respiration
- D.
All of these choices
- E.
None of these choices
Correct Answer
D. All of these choicesExplanation
Muscles produce ATP through a combination of processes. Creatine phosphate is used as a quick source of energy during short bursts of intense activity. Anaerobic cellular respiration occurs when there is not enough oxygen available, and glucose is broken down to produce ATP. Aerobic cellular respiration takes place when there is sufficient oxygen, and glucose is fully broken down in the presence of oxygen to produce ATP. Therefore, all of these choices contribute to the production of ATP in muscles.Rate this question:
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- 43.
Creatine phosphate stores and ATP together create enough energy for a muscle to contract for
- A.
15 seconds
- B.
15 minutes
- C.
1.5 minutes
- D.
Less than 5 seconds
- E.
One minute
Correct Answer
A. 15 secondsExplanation
Creatine phosphate is a high-energy molecule found in muscle cells that can rapidly regenerate ATP, the main source of energy for muscle contractions. When muscles contract, ATP is broken down into ADP and a phosphate group, releasing energy. Creatine phosphate can then donate its phosphate group to ADP, converting it back into ATP. This process allows for the rapid replenishment of ATP, providing enough energy for a muscle to contract for approximately 15 seconds.Rate this question:
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- 44.
This consists of a somatic motor neuron plus all the skeletal muscle fibers it stimulates
- A.
Sarcomere
- B.
Motor unit
- C.
Neuromuscular junction
- D.
Somatic motor neuron
- E.
Muscle fiber
Correct Answer
B. Motor unitExplanation
A motor unit consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates. This means that when the somatic motor neuron sends a signal, all the muscle fibers within that motor unit contract simultaneously. The motor unit is the functional unit responsible for generating movement in the skeletal muscles.Rate this question:
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- 45.
A single, brief contraction of all muscle fibers in a motor unit in response to a single action potential is called:
- A.
Recovery oxygen uptake
- B.
Motor unit movement
- C.
Muscle fatigue
- D.
Refractory period
- E.
Twitch contraction
Correct Answer
E. Twitch contractionExplanation
A twitch contraction refers to the brief contraction of all muscle fibers in a motor unit in response to a single action potential. This contraction is a result of the motor neuron stimulating the muscle fibers, causing them to contract simultaneously. It is called a twitch because it is a quick and involuntary contraction that lasts for a very short duration. This term is commonly used in the context of studying muscle physiology and understanding muscle contractions.Rate this question:
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- 46.
This is also referred to as the period of lost excitability
- A.
Refractory period
- B.
Contraction period
- C.
Latent period
- D.
Relaxation period
- E.
Wave summation
Correct Answer
A. Refractory periodExplanation
The refractory period is a period of time during which a nerve or muscle cell is unable to respond to a stimulus, as it is still recovering from the previous stimulus. It is often referred to as the period of lost excitability because the cell is temporarily unresponsive. This period is crucial for ensuring that nerve and muscle cells do not become overstimulated and can properly recover before being able to respond again.Rate this question:
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- 47.
A sustained contraction during which individual muscle twitches cannot be detected is called
- A.
Myogram
- B.
Muscle tone
- C.
Wave summation
- D.
Fused tetanus
- E.
Twitch
Correct Answer
D. Fused tetanusExplanation
Fused tetanus refers to a sustained contraction of a muscle where individual muscle twitches cannot be detected. This occurs when the muscle fibers are stimulated rapidly and do not have enough time to relax between contractions. As a result, the contractions blend together into a smooth, continuous contraction. This is in contrast to unfused tetanus, where individual muscle twitches can still be observed.Rate this question:
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- 48.
Increasing the number of active motor units is called:
- A.
Wave summation
- B.
Fused tetanus
- C.
Motor unit recruitment
- D.
Muscle tone
- E.
Unfused tetanus
Correct Answer
C. Motor unit recruitmentExplanation
Motor unit recruitment refers to the process of increasing the number of active motor units in a muscle. When a muscle needs to generate more force, the nervous system activates additional motor units to contract. This recruitment allows for a greater number of muscle fibers to be stimulated, resulting in a stronger contraction. It is an important mechanism for increasing muscle strength and is commonly seen during activities that require more force, such as lifting heavy weights or performing intense exercise.Rate this question:
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- 49.
This is the least powerful type of muscle fiber
- A.
Slow oxidative fiber
- B.
Fast oxidative fibers
- C.
Fast glycolytic fibers
- D.
Slow glycolytic fibers
- E.
All muscle fibers are equally capable of producing force
Correct Answer
A. Slow oxidative fiberExplanation
Slow oxidative fibers are the least powerful type of muscle fiber. These fibers have a high capacity for aerobic metabolism and are resistant to fatigue. They are primarily used for endurance activities such as long-distance running or cycling. Slow oxidative fibers have a slower contraction speed and lower force production compared to other types of muscle fibers.Rate this question:
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- 50.
A unique characteristic of cardiac muscle tissue is
- A.
Myosin
- B.
Tropomysoin
- C.
Sarcomeres
- D.
Intercalated discs
- E.
Striations
Correct Answer
D. Intercalated discsExplanation
Intercalated discs are a unique characteristic of cardiac muscle tissue. These specialized structures connect individual cardiac muscle cells, allowing for coordinated contraction of the entire heart. Intercalated discs contain gap junctions, which facilitate the rapid spread of electrical signals between cells, ensuring synchronous contraction. This unique feature is essential for the efficient pumping action of the heart and distinguishes cardiac muscle from other types of muscle tissue.Rate this question:
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Mar 21, 2023Quiz Edited by
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Apr 17, 2012Quiz Created by
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