Anatomy Test Part 2
(70).webp "Anatomy Test Part 2 - Quiz")
Questions and Answers
- 1.
This is a band of connective tissue that surrounds 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 muscles. It provides support and protection to the muscle fibers and helps to maintain the structural integrity of the muscle. It also allows for the transmission of forces generated by the muscle during contraction.Rate this question:
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- 2.
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 type of connective tissue that extends as a broad flat layer. It is different from a tendon, which is a dense connective tissue that attaches muscle to bone. The other options, perimysium, deep fascia, fascicle, and endomysium, do not accurately describe a tendon that extends as a broad flat layer.Rate this question:
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- 3.
For every nerve that penetrates a skeletal muscle there are 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 single artery to supply it with oxygenated blood and one or two veins to carry away deoxygenated blood and waste products.Rate this question:
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- 4.
Axon terminal clusters at the ends of neuromuscular junctions are referred to as:
- A.
Myelin bulbs
- B.
Neuromuscular bulbs
- C.
Synaptic end bulbs
- D.
Axon collateral bulbs
- E.
Tubule bulbs
Correct Answer
C. Synaptic end bulbsExplanation
Synaptic end bulbs are the correct answer because they are the clusters of axon terminals found at the ends of neuromuscular junctions. These bulbs contain synaptic vesicles that store neurotransmitters, which are released into the synaptic cleft to transmit signals from the neuron to the muscle fiber. The term "synaptic" refers to the connection between neurons, while "end bulbs" specifically describes the bulb-like structure at the end of the axon terminal.Rate this question:
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- 5.
After the fusion of myoblasts, the muscle fiber loses its ability to do what?
- A.
Grow
- B.
Lengthen
- C.
Contract
- D.
Go through cell division
- E.
All of the answer choices
Correct Answer
D. Go through cell divisionExplanation
After the fusion of myoblasts, the muscle fiber loses its ability to go through cell division. This is because myoblasts are the precursor cells that fuse together to form muscle fibers. Once fusion occurs, the muscle fiber is formed and it becomes a mature, differentiated cell that is specialized for contraction. As a mature cell, it no longer undergoes cell division like myoblasts do. Therefore, the muscle fiber cannot go through cell division after fusion.Rate this question:
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- 6.
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 -
- 7.
The mitochondria in muscle fiber are arranged
- A.
Randomly throughout the sarcoplasm.
- B.
In circles around the T-tubules.
- C.
Around the nuclei
- D.
In rows near the contractile muscle proteins.
- E.
Close to the sarcolemma
Correct Answer
D. In rows near the contractile muscle proteins.Explanation
The mitochondria in muscle fibers are arranged in rows near the contractile muscle proteins. This arrangement allows for efficient energy production and distribution to the areas of the muscle that require it the most during contraction. By being located near the contractile proteins, the mitochondria can quickly generate ATP, the energy currency of cells, and provide it to the muscles for contraction. This organization ensures that the energy needs of the muscle are met effectively.Rate this question:
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- 8.
These are the contractile organelles of the muscle fiber.
- A.
Myofibrils
- B.
Myoglobin
- C.
Mitochondria
- D.
Z discs
- E.
M lines
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 thick and thin filaments, myofibrils are organized into repeating units called sarcomeres, which give muscles their striped appearance. These sarcomeres contain the proteins actin and myosin, which interact to generate the force required for muscle contraction. Therefore, myofibrils are the correct answer as they play a crucial role in muscle contraction.Rate this question:
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- 9.
This part of the skeletal muscle cell releases calcium when stimulated by the T tubules.
- A.
Myofibrils
- B.
Mitochondria
- C.
Terminal cisterns of sarcoplasmic reticulum
- D.
T-tubules
- E.
None of the answer choices
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 release is a crucial step in muscle contraction, as it allows the interaction between actin and myosin filaments, leading to muscle contraction. The T tubules are invaginations of the sarcolemma that allow the action potential to reach deep into the muscle fiber, triggering the release of calcium from the terminal cisterns. The myofibrils are the contractile units of the muscle cell, while mitochondria are responsible for energy production. None of the answer choices are correct except for the terminal cisterns of the sarcoplasmic reticulum.Rate this question:
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- 10.
The sarcoplasmic reticulum is used for storing
- A.
Oxygen
- B.
ATP
- C.
PO43-.
- 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, as they bind to proteins within the muscle fibers, allowing them to slide past each other and generate force. When a muscle is at rest, the sarcoplasmic reticulum actively pumps calcium ions from the cytoplasm into its storage compartments. During muscle contraction, the sarcoplasmic reticulum releases stored calcium ions, triggering the contraction process. Therefore, the correct answer is Ca2+.Rate this question:
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- 11.
Which of the following contain thin filaments.
- A.
I band
- B.
A band
- C.
H zone
- D.
Both I band and A band
- E.
All of these answer choices are correct
Correct Answer
D. Both I band and A bandExplanation
Both the I band and A band contain thin filaments. The I band is composed of thin filaments called actin, which anchor to the Z line and extend towards the center of the sarcomere. The A band, on the other hand, contains both thick filaments (myosin) and thin filaments (actin), with the thin filaments overlapping the thick filaments. Therefore, both the I band and A band contribute to the presence of thin filaments in the sarcomere.Rate this question:
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- 12.
Which of the following contain thick filament?
- A.
Zone of overlap
- B.
A band
- C.
H zone
- D.
Both A band and H zone
- E.
All of the above
Correct Answer
E. All of the aboveExplanation
All of the options mentioned in the question contain thick filament. The zone of overlap refers to the region where thin and thick filaments overlap, the A band refers to the region where thick filaments are present, and the H zone refers to the region within the A band where only thick filaments are present. Therefore, all of these options contain thick filaments.Rate this question:
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- 13.
Myofibrils contain
- A.
Contractile proteins.
- B.
Regulatory proteins.
- C.
Structural proteins.
- D.
All of these answers are correct.
- E.
None of these answers are correct.
Correct Answer
D. All of these answers are correct.Explanation
The correct answer is all of these answers are correct. Myofibrils are composed of various proteins that perform different functions. Contractile proteins, such as actin and myosin, are responsible for the actual contraction of the muscle. Regulatory proteins, such as troponin and tropomyosin, regulate the interaction between actin and myosin. Structural proteins, such as titin and dystrophin, provide support and stability to the myofibrils. Therefore, all of these proteins are present in myofibrils, making all the given answers correct.Rate this question:
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- 14.
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 functions as a motor protein in all three types of muscle tissue. It is responsible for the movement of muscles by interacting with actin filaments and generating the force required for muscle contraction. Myosin is a key component of the sliding filament theory, which explains how muscles contract and generate movement. It is found in skeletal muscle, cardiac muscle, and smooth muscle, making it the only option that is present in all three types of muscle tissue.Rate this question:
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- 15.
What regulatory proteins can be found on an actin molecule?
- A.
Troponin and titin
- B.
Tropomyosin and troponin
- C.
Myosin and titin
- D.
Titin and tropomyosin
- E.
Tropomyosin and myosin
Correct Answer
B. Tropomyosin and troponinExplanation
Tropomyosin and troponin are regulatory proteins that can be found on an actin molecule. Tropomyosin is a long, filamentous protein that wraps around the actin filament, blocking the myosin binding sites and preventing muscle contraction. Troponin is a complex of three subunits that is attached to tropomyosin. It regulates muscle contraction by binding to calcium ions and causing a conformational change in tropomyosin, exposing the myosin binding sites and allowing muscle contraction to occur.Rate this question:
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- 16.
Titin is found in a sarcomere
- A.
The A band only
- B.
The H zone only
- C.
The zone of overlap only
- D.
From M line to Z disc
- E.
The I band only
Correct Answer
D. From M line to Z discExplanation
Titin is a protein that is found in the sarcomere, which is the basic unit of muscle contraction. 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 "from M line to Z disc".Rate this question:
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- 17.
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 responsible for reinforcing the sarcolemma, which is the cell membrane of muscle fibers. It plays a crucial role in maintaining the structural integrity of muscle cells and preventing damage during muscle contractions. Mutations in the dystrophin gene can lead to muscular dystrophy, a group of genetic disorders characterized by progressive muscle weakness and degeneration.Rate this question:
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- 18.
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 lineExplanation
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.Rate this question:
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- 19.
The sarcoplasmic reticulum releases calcium ions into the cytosol
- A.
At the beginning of a contraction
- B.
In response to acetylcholine binding to Ca2+ release channels.
- C.
By active transport using Ca2+ pumps in the SR membrane.
- D.
After the contraction ends.
- E.
All of these answers are correct.
Correct Answer
A. At the beginning of a contractionExplanation
The sarcoplasmic reticulum releases calcium ions into the cytosol at the beginning of a contraction. This is because the release of calcium ions is necessary for muscle contraction to occur. When a muscle is stimulated, acetylcholine binds to Ca2+ release channels, triggering the release of calcium ions from the sarcoplasmic reticulum into the cytosol. This increase in calcium concentration in the cytosol allows for the interaction between actin and myosin filaments, leading to muscle contraction. Therefore, the correct answer is that the sarcoplasmic reticulum releases calcium ions at the beginning of a contraction in response to acetylcholine binding to Ca2+ release channels.Rate this question:
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- 20.
What energizes the myosin head?
- A.
The actin filaments
- B.
Calcium ions
- C.
Potassium ions
- D.
ATP hydrolysis reaction
- E.
ADP synthesis
Correct Answer
D. ATP hydrolysis reactionExplanation
The myosin head is energized by the ATP hydrolysis reaction. ATP, or adenosine triphosphate, is a molecule that stores and releases energy in cells. In the presence of ATP, the myosin head binds to actin filaments and undergoes a conformational change, allowing it to pull the actin and generate muscle contraction. During this process, ATP is hydrolyzed into ADP (adenosine diphosphate) and inorganic phosphate, releasing energy that is used to power the movement of the myosin head. Therefore, the ATP hydrolysis reaction is responsible for energizing the myosin head.Rate this question:
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- 21.
What is needed for the contraction cycle to continue?
- A.
ATP and acetylcholine (ACh)
- B.
Calcium ions and ATP
- C.
ACh and potassium ions
- D.
Sodium ions and ATP
- E.
Calcium and ACh
Correct Answer
B. Calcium ions and ATPExplanation
The contraction cycle in muscle cells requires calcium ions and ATP. Calcium ions are necessary for the binding of myosin to actin, which leads to muscle contraction. ATP provides the energy needed for the myosin heads to detach from actin and reset for the next contraction. Without calcium ions and ATP, the contraction cycle cannot continue.Rate this question:
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- 22.
The signal to excite a muscle cell must cross the neuromuscular junction by the diffusion of acetylcholine across the
- A.
Node of Ranvier
- B.
Synaptic cleft
- C.
Sarcolemma
- D.
Synaptic end bulb
- E.
Transverse tubule
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 axon terminal of the motor neuron and the muscle cell. Acetylcholine, a neurotransmitter, is released from the axon terminal and diffuses across the synaptic cleft to bind to receptors on the muscle cell. This binding triggers a series of events that ultimately lead to muscle contraction. Therefore, the synaptic cleft is the correct answer as it is the site where acetylcholine diffuses to transmit the signal to the muscle cell.Rate this question:
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- 23.
Creatine phosphate and ATP together create enough energy for a muscle to contract for
- A.
15 seconds.
- B.
15 minutes.
- C.
1.5 minutes.
- D.
5 seconds.
- E.
One minute.
Correct Answer
A. 15 seconds.Explanation
Creatine phosphate and ATP are both energy sources that provide the necessary fuel for muscle contractions. Creatine phosphate is used as a rapid source of energy, while ATP is the primary energy currency of cells. Together, they work to replenish and sustain the energy needed for muscle contractions. However, the limited amount of creatine phosphate and ATP stored in muscles can only support contractions for a short period of time. Therefore, the correct answer is 15 seconds, as this is the approximate duration that the available energy can last.Rate this question:
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- 24.
This consists of a somatic motor neuron plus all the skeletal muscle fibers it stimulates.
- A.
Sarcomere
- B.
Motor unit
- C.
Neuromuscular junction
- D.
Muscle unit
- E.
Multi-unit smooth muscle
Correct Answer
B. Motor unitExplanation
A motor unit consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates. When the motor neuron is activated, it sends an electrical signal to the muscle fibers, causing them to contract. This coordinated contraction of multiple muscle fibers allows for precise control and movement. Therefore, the motor unit is the correct answer in this context.Rate this question:
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- 25.
This is a brief contraction of all muscle fibers in a motor unit in response to a single action potential.
- A.
Isometric contraction.
- B.
Isotonic contraction.
- C.
Tetany.
- D.
Refractory period.
- E.
Twitch contraction.
Correct Answer
E. Twitch contraction.Explanation
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 characterized by a quick and involuntary muscle movement. It is different from isotonic contraction, which involves muscle fibers shortening and producing movement, and isometric contraction, which involves muscle fibers generating force without changing length. Tetany refers to a sustained contraction, while the refractory period is a period of time during which a muscle fiber cannot be stimulated again.Rate this question:
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- 26.
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 the correct answer because it refers to the period of time after a neuron or muscle cell has fired an action potential or contracted, during which it is temporarily unable to respond to another stimulus. This period is often characterized by a loss of excitability, as the cell needs time to reset and restore its ion concentrations. Therefore, the term "period of lost excitability" accurately describes the refractory period.Rate this question:
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- 27.
A sustained contraction is
- A.
Unfused tetanus
- B.
Muscle atrophy.
- C.
Flaccidity.
- D.
Fused tetanus.
- E.
Wave summation.
Correct Answer
D. Fused tetanus.Explanation
Fused tetanus refers to a sustained contraction of a muscle where individual twitches fuse together and the muscle remains in a state of maximum contraction. This occurs when the frequency of nerve impulses is high enough that each new twitch starts before the previous one has completely relaxed. As a result, the muscle fibers are unable to relax fully, leading to a continuous contraction. This is different from unfused tetanus, where the twitches are not completely fused together, and wave summation, where the twitches increase in intensity but do not fuse. Muscle atrophy refers to the wasting away of muscle tissue, while flaccidity refers to a lack of muscle tone.Rate this question:
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- 28.
Increasing the number of active motor units is called
- A.
Wave summation
- B.
Fused tetanus.
- C.
Motor unit recruitment.
- D.
Muscle tone.
- E.
Flaccidity.
Correct Answer
C. Motor unit recruitment.Explanation
Motor unit recruitment refers to the process of increasing the number of active motor units in a muscle. Motor units are composed of a motor neuron and the muscle fibers it innervates. When more motor units are recruited, more muscle fibers are activated, resulting in increased muscle force and contraction. This process is essential for generating stronger muscle contractions and is often seen during activities that require increased force production, such as lifting heavy weights or running at high speeds.Rate this question:
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- 29.
This is the least powerful type of muscle fiber.
- A.
Slow oxidative fiber
- B.
Fast oxidative fiber
- C.
Fast glycolytic fiber
- D.
Slow glycolytic fiber
- E.
None of these choices.
Correct Answer
A. Slow oxidative fiberExplanation
Slow oxidative fiber is the least powerful type of muscle fiber because it has a slower contraction time and lower force production compared to other types of muscle fibers. These fibers are primarily used for endurance activities and are highly resistant to fatigue. They rely on oxidative metabolism to produce energy, which allows them to sustain contractions for longer periods of time. However, due to their slower contraction speed and lower force production, they are not as powerful as fast oxidative or fast glycolytic fibers.Rate this question:
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- 30.
Which of the below structures is found in cardiac muscle tissue but not skeletal muscle tissue?
- A.
Myosin
- B.
Tropomyosin
- C.
Sarcomeres
- D.
Intercalated discs
- E.
Striations
Correct Answer
D. Intercalated discsExplanation
Intercalated discs are found in cardiac muscle tissue but not in skeletal muscle tissue. These specialized structures are responsible for connecting individual cardiac muscle cells, allowing them to work together as a coordinated unit. Intercalated discs contain gap junctions, which enable electrical impulses to pass quickly from one cell to another, facilitating synchronized contractions of the heart. In contrast, skeletal muscle tissue does not have intercalated discs, as skeletal muscle cells are not required to contract in a coordinated manner.Rate this question:
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- 31.
Which of the following exhibits autorhythmicity?
- A.
Cardiac muscle
- B.
Slow twitch oxidative skeletal muscle
- C.
Multi-unit smooth muscle
- D.
Fast twitch glycolytic skeletal muscle
- E.
All of these choices are correct.
Correct Answer
A. Cardiac muscleExplanation
Cardiac muscle exhibits autorhythmicity, which means it has the ability to generate its own electrical impulses and contract rhythmically without any external stimulation. This is important for the heart to maintain its regular pumping action. Unlike other muscle types, cardiac muscle cells are interconnected and form a specialized network called the cardiac conduction system. This system coordinates the electrical signals and ensures that the heart beats in a synchronized and coordinated manner. Therefore, cardiac muscle is the correct answer as it demonstrates autorhythmicity.Rate this question:
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- 32.
Smooth muscle tone is due to the prolonged presence of what in the cytosol?
- A.
ATP
- B.
Calcium ions
- C.
Phosphate ions
- D.
Myoglobin
- E.
None of these choices.
Correct Answer
B. Calcium ionsExplanation
Smooth muscle tone is maintained by the prolonged presence of calcium ions in the cytosol. Calcium ions play a crucial role in smooth muscle contraction by binding to specific proteins called calmodulin, which activates myosin light chain kinase. This enzyme then phosphorylates myosin, initiating the contraction process. Therefore, the correct answer is calcium ions.Rate this question:
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- 33.
Hyperplasia is
- A.
An increase in the size of muscle fibers.
- B.
A decrease in the size of muscle fibers.
- C.
An increase in the number of muscle fibers.
- D.
A decrease in the number of muscle fibers.
- E.
None of these choices.
Correct Answer
C. An increase in the number of muscle fibers.Explanation
Hyperplasia refers to an increase in the number of muscle fibers. This means that the total number of muscle cells in a particular muscle or tissue increases. It is different from hypertrophy, which is an increase in the size of individual muscle fibers. In hyperplasia, the muscle fibers multiply, leading to an overall increase in muscle mass.Rate this question:
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- 34.
Which of the following is not a function of the nervous system?
- A.
Sensory function
- B.
Integrative function
- C.
Motor function
- D.
All of the above are functions of the nervous system
Correct Answer
D. All of the above are functions of the nervous systemExplanation
The given answer states that all of the options listed (sensory function, integrative function, and motor function) are functions of the nervous system. This means that each of these functions is performed by the nervous system. The nervous system is responsible for receiving sensory information from the environment, integrating and processing this information, and then sending out motor signals to initiate appropriate actions. Therefore, all of the options listed are indeed functions of the nervous system.Rate this question:
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- 35.
The peripheral nervous system can be divided into:
- A.
Somatic nervous system
- B.
Autonomic nervous system
- C.
Enteric nervous system
- D.
All of these choices
Correct Answer
D. All of these choicesExplanation
The peripheral nervous system refers to the nerves and ganglia outside of the brain and spinal cord. It can be divided into three main divisions: the somatic nervous system, which controls voluntary movements and sensory information; the autonomic nervous system, which controls involuntary functions like heart rate and digestion; and the enteric nervous system, which controls the gastrointestinal system. Therefore, all of these choices are correct divisions of the peripheral nervous system.Rate this question:
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- 36.
The motor portion of the autonomic nervous system can be divided into:
- A.
Somatic and sympathetic divisions.
- B.
Somatic and parasympathetic divisions.
- C.
Enteric and somatic divisions.
- D.
Sympathetic and parasympathetic divisions.
- E.
Voluntary and involuntary divisions.
Correct Answer
D. Sympathetic and parasympathetic divisions.Explanation
The motor portion of the autonomic nervous system can be divided into the sympathetic and parasympathetic divisions. The sympathetic division is responsible for the body's fight-or-flight response, activating processes that increase heart rate, dilate blood vessels, and release stress hormones. On the other hand, the parasympathetic division is responsible for the body's rest-and-digest response, promoting processes such as digestion, slowing heart rate, and conserving energy. These two divisions work in opposition to maintain homeostasis in the body.Rate this question:
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- 37.
This has the property of electrical excitability.
- A.
Muscle cells
- B.
Neurons
- C.
All of these choices
- D.
None of these choices
Correct Answer
C. All of these choicesExplanation
All of these choices have the property of electrical excitability. Muscle cells and neurons are both types of cells that are capable of generating and conducting electrical signals. Muscle cells are responsible for contraction and movement, and neurons are responsible for transmitting electrical signals in the nervous system. Therefore, both muscle cells and neurons exhibit electrical excitability. Since the answer states "all of these choices," it implies that both muscle cells and neurons possess this property, making it the correct answer.Rate this question:
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- 38.
This is the site of protein synthesis in a neuron.
- A.
Mitochondria
- B.
Nucleus
- C.
Nissl body
- D.
Golgi apparatus
- E.
Nucleolus
Correct Answer
C. Nissl bodyExplanation
The Nissl body, also known as Nissl substance or Nissl granules, is a specialized region within the neuron's cell body where protein synthesis takes place. It is composed of rough endoplasmic reticulum (ER) and ribosomes, which are responsible for synthesizing proteins needed for the neuron's function and structure. The Nissl body is particularly abundant in neurons that have high protein synthesis requirements, such as those involved in transmitting electrical signals. Therefore, it is the site of protein synthesis in a neuron.Rate this question:
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- 39.
Nerve fiber refers to:
- A.
An axon.
- B.
A dendrite
- C.
A Nissl body.
- D.
Both axons and dendrites.
- E.
All of these choices
Correct Answer
D. Both axons and dendrites.Explanation
The term "nerve fiber" refers to both axons and dendrites. Axons are long, slender projections of nerve cells that transmit electrical impulses away from the cell body, while dendrites are shorter, branched projections that receive electrical impulses from other cells. Therefore, the correct answer is that nerve fiber refers to both axons and dendrites.Rate this question:
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- 40.
This type of neuron has one main dendrite and one main axon.
- A.
Multipolar neuron
- B.
Bipolar neuron
- C.
Unipolar neuron
- D.
Purkinje cell
- E.
Renshaw cell
Correct Answer
B. Bipolar neuronExplanation
A bipolar neuron is a type of neuron that has one main dendrite and one main axon. This means that it has two processes extending from the cell body - one for receiving signals (dendrite) and one for sending signals (axon). This type of neuron is commonly found in sensory organs such as the retina of the eye and the olfactory epithelium in the nose, where it is involved in relaying sensory information to the brain.Rate this question:
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- 41.
Schwann cells begin to form myelin sheaths around axons
- A.
When neurons are injured
- B.
During fetal development.
- C.
After birth.
- D.
Only in response to electrical stimulation by neuroglial cells.
- E.
During the early onset of Alzheimer’s disease.
Correct Answer
B. During fetal development.Explanation
During fetal development, Schwann cells begin to form myelin sheaths around axons. This process is crucial for the proper functioning of the nervous system. Myelin sheaths help to insulate and protect the axons, allowing for efficient transmission of electrical signals. This development occurs before birth and continues throughout early childhood. After birth, Schwann cells continue to myelinate axons in response to the maturation of the nervous system, but the initial formation of myelin sheaths occurs during fetal development.Rate this question:
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- 42.
This contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals and neruoglia.
- A.
Gray matter
- B.
White matter
- C.
Nissl bodies
- D.
Ganglia
- E.
Nuclei
Correct Answer
A. Gray matterExplanation
Gray matter refers to the regions of the central nervous system that contain neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia. It appears gray because it lacks myelin, a fatty substance that gives white matter its color. Gray matter is responsible for processing and integrating information in the brain, while white matter is responsible for transmitting signals between different areas of gray matter. Nissl bodies are structures found in the cell bodies of neurons, ganglia are clusters of cell bodies outside the central nervous system, and nuclei are collections of cell bodies within the central nervous system.Rate this question:
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- 43.
Which is not a type of channel used in production of an electrical signal in neurons?
- A.
Leakage channel
- B.
Voltage-gated channel
- C.
Ligand-gated channel
- D.
Mechanically gated channel
- E.
Ion-gated channel
Correct Answer
E. Ion-gated channelExplanation
Ion-gated channel is not a type of channel used in the production of an electrical signal in neurons. Leakage channels, voltage-gated channels, ligand-gated channels, and mechanically gated channels are all types of channels that play a role in the generation and transmission of electrical signals in neurons. Ion-gated channel is not a recognized term in neuroscience and does not accurately describe any known type of channel involved in neuronal signaling.Rate this question:
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- 44.
The resting membrane potential in neurons ranges from:
- A.
+5 to 100 mV
- B.
–25 to –70 mV
- C.
–40 to –90 mV
- D.
–90 to 5 mV
- E.
None of these choices
Correct Answer
C. –40 to –90 mVExplanation
The resting membrane potential in neurons refers to the electrical charge difference across the cell membrane when the neuron is not actively sending a signal. This potential typically ranges from -40 to -90 mV. This negative potential is maintained by the balance of ions inside and outside the cell, with higher concentrations of sodium ions outside and higher concentrations of potassium ions inside. This potential is important for the neuron's ability to generate and transmit electrical signals.Rate this question:
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- 45.
A polarized cell
- A.
Has a charge imbalance across its membrane.
- B.
Includes most cells of the body.
- C.
Exhibits a membrane potential.
- D.
Includes most cells of the body and exhibits a membrane potential.
- E.
ALL of the choices
Correct Answer
E. ALL of the choicesExplanation
The correct answer is "ALL of the choices." This is because a polarized cell refers to any cell that has a charge imbalance across its membrane, which is true for all cells of the body. Additionally, a polarized cell exhibits a membrane potential, which is also true for all cells. Therefore, all of the given choices accurately describe a polarized cell.Rate this question:
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- 46.
Sodium pumps are considered electrogenic because
- A.
It contributes to the negativity of the resting membrane potential.
- B.
The sodium ions are negatively charged.
- C.
It exhibits low permeability.
- D.
Both it contributes to the negativity of the resting membrane potential and the sodium ions are negatively charged.
- E.
All of these choices
Correct Answer
A. It contributes to the negativity of the resting membrane potential.Explanation
The correct answer is "it contributes to the negativity of the resting membrane potential." This is because sodium pumps actively transport sodium ions out of the cell, creating a higher concentration of sodium ions outside the cell compared to inside. This concentration gradient contributes to the negativity of the resting membrane potential, as there are more positively charged sodium ions outside the cell than inside.Rate this question:
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- 47.
A depolarizing graded potential
- A.
Makes the membrane more polarized.
- B.
Makes the membrane less polarized
- C.
Is considered a type of action potential.
- D.
Is the last part of an action potential.
- E.
Is seen when the cell approaches threshold.
Correct Answer
B. Makes the membrane less polarizedExplanation
A depolarizing graded potential refers to a change in the membrane potential that makes it less polarized. This means that the potential becomes less negative, bringing it closer to zero or even becoming positive. This change in membrane potential occurs when the cell receives excitatory signals, causing the opening of ion channels that allow positive ions to enter the cell. As a result, the membrane becomes less polarized and more likely to reach the threshold for generating an action potential.Rate this question:
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- 48.
When a depolarizing graded potential makes the membrane depolarize to threshold
- A.
Ligand-gated Ca+2 channels close rapidly.
- B.
Voltage-gated Ca+2 channels open rapidly.
- C.
Ligand-gated Na+ channels close rapidly.
- D.
Voltage-gated Na+ channels open rapidly.
- E.
None of these choices occur.
Correct Answer
D. Voltage-gated Na+ channels open rapidly.Explanation
When a depolarizing graded potential makes the membrane depolarize to threshold, voltage-gated Na+ channels open rapidly. This allows an influx of Na+ ions into the cell, causing further depolarization and the generation of an action potential. The opening of these channels is essential for the propagation of the action potential along the neuron.Rate this question:
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- 49.
During the resting state of a voltage gated Na+ channel 1. the inactivation gate is open. 2. the activation gate is closed. 3. the channel is permeable to Na+.
- A.
1 only
- B.
2 only
- C.
3 only
- D.
Both 1 and 2 are true.
- E.
All of these choices are true.
Correct Answer
D. Both 1 and 2 are true.Explanation
During the resting state of a voltage gated Na+ channel, both the inactivation gate is open and the activation gate is closed. This means that the channel is not allowing the flow of Na+ ions through it. The inactivation gate being open indicates that the channel is ready to be activated, while the closed activation gate prevents the flow of ions until the channel is properly stimulated. Therefore, both statements 1 and 2 are true during the resting state of a voltage gated Na+ channel.Rate this question:
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- 50.
During which period can a second action potential be initiated by a larger than normal stimulus?
- A.
Latent period
- B.
Absolute refractory period
- C.
Relative refractory period
- D.
All of these choices
- E.
None of these choices
Correct Answer
C. Relative refractory periodExplanation
During the relative refractory period, the membrane potential of a neuron is hyperpolarized but gradually returning to its resting state. This means that a larger than normal stimulus can still generate a second action potential, although it would require a stronger stimulus compared to the initial action potential. Therefore, during the relative refractory period, a second action potential can be initiated by a larger than normal stimulus.Rate this question:
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Apr 16, 2024Quiz Edited by
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May 09, 2012Quiz Created by
Bowchicka777
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