A&p Muscle And Nervous System
Questions and Answers
- 1.
Which of the following structures is not part of the central nervous system?
- A.
The brain
- B.
A nerve
- C.
The spinal cord
- D.
A tract
Correct Answer
B. A nerveExplanation
A nerve is not part of the central nervous system. The central nervous system consists of the brain and spinal cord, which are responsible for processing and coordinating information. Nerves, on the other hand, are part of the peripheral nervous system, which connects the central nervous system to the rest of the body. Nerves transmit signals to and from the central nervous system, allowing for communication between the brain and other parts of the body. Therefore, a nerve is not considered part of the central nervous system.Rate this question:
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- 2.
Identify which type(s) of supporting cell is being described. Myelinates nerve fibers in the CNS
- A.
Astrocyte
- B.
Ependymal cell
- C.
Microgilia
- D.
Oligodendrocyte
- E.
Satellite cell
- F.
Schwann cell
Correct Answer
F. Schwann cellExplanation
The correct answer is schwann cell. Schwann cells are a type of supporting cell that myelinates nerve fibers in the peripheral nervous system (PNS). They wrap around and insulate nerve fibers, allowing for faster transmission of electrical signals. In contrast, oligodendrocytes are the type of supporting cells that myelinate nerve fibers in the central nervous system (CNS). Astrocytes, ependymal cells, microglia, satellite cells are other types of supporting cells in the nervous system with different functions.Rate this question:
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- 3.
Lines brain cavities
- A.
Astrocyte
- B.
Ependymal cell
- C.
Satellite cell
Correct Answer
B. Ependymal cellExplanation
Ependymal cells are a type of glial cell that line the cavities of the brain. They are responsible for producing cerebrospinal fluid (CSF) and helping to circulate it throughout the brain and spinal cord. Ependymal cells have cilia on their surface, which aid in the movement of CSF. These cells also play a role in regulating the chemical composition of the CSF and providing structural support to the brain. Overall, ependymal cells contribute to the maintenance of a stable brain environment and the proper functioning of the central nervous system.Rate this question:
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- 4.
Myelinates nerve fibers in the PNS
- A.
Schwann cell
- B.
Oligodendrocyte
- C.
Microgilia
Correct Answer
A. Schwann cellExplanation
Schwann cells are responsible for myelinating nerve fibers in the peripheral nervous system (PNS). Myelination is the process of forming a protective covering around nerve fibers, which allows for faster and more efficient conduction of electrical impulses. Schwann cells wrap around individual nerve fibers, forming multiple layers of myelin sheaths. In contrast, oligodendrocytes are responsible for myelinating nerve fibers in the central nervous system (CNS), and microglia are immune cells that protect the CNS by removing damaged cells and foreign substances. Therefore, the correct answer is Schwann cell.Rate this question:
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- 5.
CNS Phagocytes
- A.
Ependymal cell
- B.
Microgilia
- C.
Astrocyte
Correct Answer
B. MicrogiliaExplanation
Microglia are a type of phagocytic cells found in the central nervous system (CNS). They are the resident immune cells in the brain and spinal cord, responsible for immune surveillance and defense against pathogens. Microglia are derived from macrophages and play a crucial role in maintaining brain homeostasis. They are involved in the clearance of dead cells, debris, and pathogens through phagocytosis. Additionally, microglia also participate in neuroinflammation and contribute to the immune response in the CNS. Therefore, microglia is the correct answer in this context.Rate this question:
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- 6.
Helps regulate the ionic composition of CNS extracellular fluid
- A.
Astrocytes
- B.
Schwann cells
- C.
Satellite cells
Correct Answer
A. AstrocytesExplanation
Astrocytes are a type of glial cell found in the central nervous system (CNS). One of their main functions is to regulate the ionic composition of the extracellular fluid in the CNS. They help maintain the balance of ions such as potassium, sodium, and calcium, which is crucial for proper neuronal function. Astrocytes also play a role in neurotransmitter clearance and recycling, as well as providing structural support to neurons. Therefore, astrocytes are the correct answer as they are directly involved in regulating the ionic composition of the CNS extracellular fluid.Rate this question:
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- 7.
What type of current flows through the axolemma during the steep phase of repolarization?
- A.
Chiefly a sodium current
- B.
Chiefly a potassium current
- C.
Sodium and potassium current
Correct Answer
B. Chiefly a potassium currentExplanation
During the steep phase of repolarization, the axolemma experiences a change in electrical potential, causing the cell to return to its resting state. This is primarily achieved through the movement of potassium ions out of the cell. As potassium channels open, potassium ions flow out of the cell, leading to an efflux of positive charge and repolarization. Therefore, the correct answer is chiefly a potassium current.Rate this question:
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- 8.
Assume that an EPSP is being generated on the dendritic membrane. Which will occur?
- A.
Specific Na+ channels will open
- B.
Specific K+ channels will open
- C.
A single type of channel will open, permitting simultaneous flow of Na+ and K+
- D.
Na+ channels will open first and then close as K+ channels open
Correct Answer
C. A single type of channel will open, permitting simultaneous flow of Na+ and K+Explanation
When an EPSP (Excitatory Postsynaptic Potential) is generated on the dendritic membrane, a single type of channel will open, allowing the simultaneous flow of Na+ (sodium) and K+ (potassium) ions. This is known as a non-selective cation channel. The opening of these channels allows both Na+ and K+ ions to move across the membrane, which can depolarize the neuron and contribute to the generation of an action potential.Rate this question:
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- 9.
The velocity of nerve impulse conduction is greatest in
- A.
Heavily myelinated, large-diameter fibers
- B.
Myelinated, small-diameter fibers
- C.
Unmyelinated, small-diameter fibers
- D.
Unmyelinated, large-diameter fibers
Correct Answer
A. Heavily myelinated, large-diameter fibersExplanation
Heavily myelinated, large-diameter fibers have the greatest velocity of nerve impulse conduction because myelin acts as an insulating layer that allows for faster transmission of electrical signals. Additionally, the larger diameter of these fibers allows for less resistance to the flow of ions, further increasing the speed of conduction. On the other hand, myelinated, small-diameter fibers have a slower conduction velocity due to their smaller size and unmyelinated fibers have the slowest conduction velocity as they lack the insulation provided by myelin.Rate this question:
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- 10.
Chemical synapses are characterized by all of the following except
- A.
The release of neurotransmitter by the presynaptic membranes
- B.
Postsynaptic membranes bearing receptors that bind neurotransmitter
- C.
Ions flowing through protein channels from the presynaptic to the postsynaptic neuron
- D.
A fluid-filled gap seperating the nuerons
Correct Answer
C. Ions flowing through protein channels from the presynaptic to the postsynaptic neuronExplanation
Chemical synapses are characterized by the release of neurotransmitter by the presynaptic membranes, postsynaptic membranes bearing receptors that bind neurotransmitter, and a fluid-filled gap separating the neurons. However, ions flowing through protein channels from the presynaptic to the postsynaptic neuron is not a characteristic of chemical synapses. Instead, this is a characteristic of electrical synapses, where ions directly flow from one neuron to another through gap junctions.Rate this question:
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- 11.
Biogenic amine neurotransmitters include all but
- A.
Norepinephrine
- B.
Acetylcholine
- C.
Dopamine
- D.
Serotonin
Correct Answer
B. AcetylcholineExplanation
Acetylcholine is not a biogenic amine neurotransmitter. Biogenic amine neurotransmitters are a specific group of neurotransmitters that are derived from amino acids and play important roles in the central nervous system. Norepinephrine, dopamine, and serotonin are all examples of biogenic amine neurotransmitters. Acetylcholine, on the other hand, is a neurotransmitter that is derived from choline and is not classified as a biogenic amine.Rate this question:
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- 12.
The neuropeptides that act as natural opiates are:
- A.
Substance P
- B.
Somatostatin
- C.
Cholecystokinin
- D.
Enkephalins
Correct Answer
D. EnkephalinsExplanation
Enkephalins are neuropeptides that act as natural opiates. These small molecules are produced by the body and play a role in pain relief and mood regulation. They bind to specific receptors in the brain and spinal cord, inhibiting the transmission of pain signals and producing analgesic effects. Enkephalins are part of the endogenous opioid system, which also includes other natural opiates like endorphins. By binding to opioid receptors, enkephalins can produce feelings of euphoria and well-being.Rate this question:
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- 13.
Inhibition of acetylcholinesterase by poisoning blocks neurotransmission at the neuromuscular junction because
- A.
ACh is no longer released by the presynaptic terminal
- B.
ACh synthesis in the presynaptic terminal is blocked
- C.
ACh is not degraded, hence prolonged depolarization is enforced on the posysynaptic cell
- D.
ACh is blocked from attaching to the postsynaptic ACh receptors
Correct Answer
C. ACh is not degraded, hence prolonged depolarization is enforced on the posysynaptic cellExplanation
Inhibition of acetylcholinesterase prevents the breakdown of acetylcholine (ACh), leading to its accumulation in the synaptic cleft. This excess ACh continuously stimulates the postsynaptic cell, causing prolonged depolarization. This prolonged depolarization can lead to muscle spasms and paralysis, as neurotransmission is disrupted and the normal balance of excitation and inhibition is disturbed.Rate this question:
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- 14.
The anatomical region of a multipolart neuron that has the lowest threshold for generating an AP is the
- A.
Soma
- B.
Dendrites
- C.
Axon hillock
- D.
Distal axon
Correct Answer
C. Axon hillockExplanation
The axon hillock is the correct answer because it is the region of a multipolar neuron that has the lowest threshold for generating an action potential (AP). The axon hillock is located at the junction between the soma (cell body) and the axon. It contains a high concentration of voltage-gated ion channels, particularly sodium channels, which are responsible for initiating and propagating the action potential. Due to its high density of ion channels, the axon hillock is more excitable than other regions of the neuron, such as the dendrites or the distal axon.Rate this question:
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- 15.
An IPSP is inhibitory because
- A.
It hyperpolarizes the posysynaptic membrane
- B.
It reduces the amount of neurotransmitter released by the presynaptic terminal
- C.
It prevents calcium ion entry into the presynaptic terminal
- D.
It changes the threshold of the neuron
Correct Answer
A. It hyperpolarizes the posysynaptic membraneExplanation
An IPSP is inhibitory because it hyperpolarizes the postsynaptic membrane. Hyperpolarization refers to an increase in the membrane potential, making it more negative than the resting potential. This makes it harder for an action potential to be generated, reducing the likelihood of the neuron firing. Therefore, when an IPSP hyperpolarizes the postsynaptic membrane, it inhibits the transmission of signals between neurons, preventing the generation of an action potential and ultimately inhibiting neuronal activity.Rate this question:
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- 16.
Identify the neuronal circuits described the choosing the correct response. (1) Impulses continue around and around the circuit until one neuron stops firing.
- A.
Converging
- B.
Diverging
- C.
Parallel after-discharge
- D.
Reverberating
Correct Answer
D. ReverberatingExplanation
The correct answer is "reverberating." In a reverberating neuronal circuit, impulses continue to travel in a loop, causing a continuous feedback loop and the firing of neurons in a repetitive pattern. This type of circuit is commonly found in processes such as breathing, where the repetitive firing of neurons is necessary for the continuous movement of muscles involved in respiration.Rate this question:
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- 17.
(2) One or a few inputs ultimately influence large numbers of neurons
- A.
Converging
- B.
Diverging
- C.
Parallel after-discharge
- D.
Reverberating
Correct Answer
B. DivergingExplanation
Diverging is the correct answer because it refers to the process in which one or a few inputs influence large numbers of neurons. In a diverging pathway, a single input signal branches out and activates multiple neurons, leading to the spread of information across different neural circuits. This allows for the amplification and distribution of signals, enabling widespread communication and processing in the nervous system.Rate this question:
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- 18.
(3) Many neurons influence a few neurons
- A.
Converging
- B.
Diverging
- C.
Reverberating
- D.
Parallel after-discharge
Correct Answer
A. ConvergingExplanation
In converging neural pathways, many neurons send signals to a smaller number of neurons. This allows for the integration of information from multiple sources and the processing of complex stimuli. The converging pathway is important for sensory perception, decision-making, and memory formation. It ensures that different inputs are combined and processed in a coordinated manner, leading to a more accurate and efficient neural response.Rate this question:
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- 19.
(4) may be involved in exacting types of mental activity
- A.
Converging
- B.
Diverging
- C.
Parallel after-discharge
- D.
Reverberating
Correct Answer
C. Parallel after-dischargeExplanation
Parallel after-discharge refers to a neural circuit where a single stimulus can activate multiple pathways simultaneously, leading to prolonged and synchronized firing of neurons. This type of circuit is often associated with complex mental activities such as problem-solving, decision-making, and memory retrieval. Therefore, the statement suggests that (4) may be involved in exacting types of mental activity, as it describes a neural circuit that allows for the simultaneous activation and synchronization of multiple pathways.Rate this question:
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- 20.
A muscle that assists an agonist by causing a like movement or by stabilizing a joint over which an agonist acts is
- A.
An antagnonist
- B.
Prime mover
- C.
Synergist
- D.
Agonist
Correct Answer
C. SynergistExplanation
A synergist is a muscle that assists an agonist by causing a similar movement or by stabilizing a joint over which the agonist acts. This means that the synergist works together with the agonist to produce a coordinated movement. It helps to enhance the action of the agonist and ensure smooth and efficient movement.Rate this question:
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- 21.
The arrangement of muscle fibers in which the fibers are arranged at an angle to a central longitudinal tendon is
- A.
Circular
- B.
Longitudinal
- C.
Pennate
- D.
Parallel
Correct Answer
C. PennateExplanation
Pennate muscle fibers are arranged at an angle to a central longitudinal tendon. This arrangement allows for a greater number of muscle fibers to be packed into a smaller space, resulting in increased strength and force generation. The angle of the fibers can vary, with some pennate muscles having a more oblique angle and others having a more perpendicular angle to the tendon. This arrangement is commonly found in muscles that require a lot of strength, such as the quadriceps in the thigh.Rate this question:
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- 22.
Match the facial muscle description to the appropriate name. (1) Squints the eye
- A.
Corrugator supercilii
- B.
Zygomaticus
- C.
Obicularis oculi
Correct Answer
C. Obicularis oculiExplanation
The correct answer is obicularis oculi because this muscle is responsible for squinting the eye. The corrugator supercilii muscle is involved in frowning and wrinkling the forehead, while the zygomaticus muscle is responsible for smiling. Therefore, the obicularis oculi is the most appropriate name for the muscle that squints the eye.Rate this question:
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- 23.
(2) raises the eyebrows
- A.
Frontal belly of epicranius
- B.
Occipital belly of epicranius
- C.
Depressor anguli oris
Correct Answer
A. Frontal belly of epicraniusExplanation
The correct answer is the frontal belly of epicranius. The frontal belly of epicranius is a muscle located in the forehead region. When this muscle contracts, it raises the eyebrows, causing a visible movement in that area. The occipital belly of epicranius is located at the back of the head and is responsible for pulling the scalp backward. The depressor anguli oris is a muscle in the lower face that pulls the corners of the mouth downward. Therefore, the most appropriate answer in this context is the frontal belly of epicranius, as it specifically relates to raising the eyebrows.Rate this question:
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- 24.
(3) Smiling muscle
- A.
Obicularis oris
- B.
Zygomaticus
- C.
Corrugator supercilii
Correct Answer
B. ZygomaticusExplanation
The zygomaticus muscle is responsible for smiling. When this muscle contracts, it pulls the corners of the mouth upward, creating a smile. The other two muscles mentioned, obicularis oris and corrugator supercilii, are not specifically associated with smiling. The obicularis oris muscle is responsible for puckering the lips, while the corrugator supercilii muscle is involved in frowning or furrowing the eyebrows. Therefore, zygomaticus is the correct answer as it is directly related to the action of smiling.Rate this question:
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- 25.
(4) Puckers the lips
- A.
Depressor anguli oris
- B.
Orbicularis oculi
- C.
Orbicularis oris
Correct Answer
C. Orbicularis orisExplanation
The correct answer is orbicularis oris because this muscle is responsible for puckering the lips. It is a circular muscle that surrounds the mouth and allows for movements such as closing and protruding the lips. The other two muscles mentioned, depressor anguli oris and orbicularis oculi, are not directly involved in puckering the lips.Rate this question:
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- 26.
(5) Pulls the scalp posteriorly
- A.
Zygomaticus
- B.
Occipital belly of epicranius
- C.
Corrugator spercilii
Correct Answer
B. Occipital belly of epicraniusExplanation
The occipital belly of the epicranius muscle is responsible for pulling the scalp posteriorly. This muscle is located at the back of the head and connects to the frontalis muscle via the epicranial aponeurosis. When the occipital belly contracts, it causes the scalp to move backward, helping to create facial expressions like raising the eyebrows or wrinkling the forehead.Rate this question:
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- 27.
The primer mover of inspiration is the
- A.
Diaphragm
- B.
Internal intercostals
- C.
External intercostals
- D.
Abdominal wall muscles
Correct Answer
A. DiaphragmExplanation
The diaphragm is the primary muscle responsible for inspiration. It contracts and moves downward, causing the thoracic cavity to expand and the lungs to fill with air. This creates a pressure gradient that allows air to flow into the lungs. The internal and external intercostal muscles also play a role in inspiration by helping to elevate the ribcage and expand the chest cavity. The abdominal wall muscles are primarily involved in expiration by compressing the abdominal contents and pushing air out of the lungs.Rate this question:
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- 28.
The arm muscle that both flexes the elbow and supinates the forarm is the
- A.
Brachialis
- B.
Brachioradialis
- C.
Biceps brachii
- D.
Triceps brachii
Correct Answer
C. Biceps brachiiExplanation
The biceps brachii is the correct answer because it is the muscle that both flexes the elbow and supinates the forearm. The brachialis muscle also flexes the elbow, but it does not have the ability to supinate the forearm. The brachioradialis muscle is responsible for flexing the elbow, but it does not supinate the forearm. The triceps brachii muscle is responsible for extending the elbow, but it does not flex or supinate the forearm.Rate this question:
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- 29.
The chewing muscles that protrude the mandible and produce side-to-side grinding movements are
- A.
Buccinators
- B.
Masseters
- C.
Temporalis
- D.
Pterygoids
Correct Answer
D. PterygoidsExplanation
The chewing muscles that protrude the mandible and produce side-to-side grinding movements are the pterygoids. These muscles are located in the jaw and are responsible for moving the mandible from side to side during chewing. The pterygoids work in conjunction with other muscles such as the masseters and temporalis to facilitate proper chewing and grinding of food.Rate this question:
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- 30.
Muscles that depress the hyoid bone and larnyx include all but the
- A.
Sternohyoid
- B.
Omohyoid
- C.
Geniohyoid
- D.
Sterno-thyroid
Correct Answer
C. GeniohyoidExplanation
The geniohyoid muscle is not involved in depressing the hyoid bone and larynx. The sternohyoid, omohyoid, and sterno-thyroid muscles are responsible for depressing the hyoid bone and larynx.Rate this question:
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- 31.
Intrinsic muscles of the back that promote extension of the spine (or head) include all but
- A.
Splenius muscles
- B.
Semispinalis muscles
- C.
Scalene muscles
- D.
Erector spinae
Correct Answer
C. Scalene musclesExplanation
The scalene muscles are not intrinsic muscles of the back that promote extension of the spine. The scalene muscles are located in the neck and are responsible for various movements of the neck, such as lateral flexion and rotation. They do not directly contribute to the extension of the spine or head. On the other hand, the splenius muscles, semispinalis muscles, and erector spinae are all intrinsic muscles of the back that play a role in promoting extension of the spine or head.Rate this question:
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- 32.
Several muscles act to move and/or stabilize the scapula. Which of the following are small rectangular muscles that square the shoulders as they act together to retract the scapula?
- A.
Levator scapulae
- B.
Rhomboids
- C.
Serratus anterior
- D.
Trapezius
Correct Answer
B. RhomboidsExplanation
The rhomboids are small rectangular muscles that act together to retract the scapula. When these muscles contract, they pull the scapula towards the midline of the body, helping to square the shoulders. The levator scapulae muscle helps elevate the scapula, the serratus anterior muscle protracts the scapula, and the trapezius muscle has multiple functions including elevating, retracting, and rotating the scapula. Therefore, the correct answer is rhomboids.Rate this question:
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- 33.
The quadriceps include all but
- A.
Vastus lateralis
- B.
Vastus intermedius
- C.
Vastus medialis
- D.
Biceps femoris
- E.
Rectus femoris
Correct Answer
D. Biceps femorisExplanation
The quadriceps are a group of muscles located in the front of the thigh. They include the vastus lateralis, vastus intermedius, and vastus medialis, all of which are responsible for extending the knee joint. The biceps femoris, on the other hand, is a muscle located in the back of the thigh and is part of the hamstring muscle group, not the quadriceps. The rectus femoris is also a quadriceps muscle responsible for extending the knee and flexing the hip joint. Therefore, the biceps femoris is the correct answer as it is not included in the quadriceps muscle group.Rate this question:
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- 34.
A prime mover of hip flexion is the
- A.
Rectus femoris
- B.
Iliopsoas
- C.
Vasti muscles
- D.
Gluteus maximus
Correct Answer
B. IliopsoasExplanation
The iliopsoas muscle is a prime mover of hip flexion. It is composed of two muscles, the iliacus and the psoas major, which work together to flex the hip joint. The rectus femoris is also involved in hip flexion, but it is not the primary muscle responsible for this movement. The vasti muscles are a group of muscles in the quadriceps that primarily extend the knee, not flex the hip. The gluteus maximus is a hip extensor, meaning it works to straighten the hip joint rather than flex it. Therefore, the correct answer is iliopsoas.Rate this question:
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- 35.
The prime mover of hip extension against resistance is the
- A.
Gluteus maximus
- B.
Gluteus medius
- C.
Biceps femoris
- D.
Semi-membranosus
Correct Answer
A. Gluteus maximusExplanation
The gluteus maximus is the correct answer because it is the largest and strongest muscle in the gluteal region. It is responsible for extending the hip joint against resistance, such as when standing up from a seated position or climbing stairs. The gluteus medius, biceps femoris, and semi-membranosus are also muscles involved in hip movement, but they do not primarily function as the prime mover for hip extension against resistance.Rate this question:
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- 36.
Muscles that cause plantar flexion include all but the
- A.
Gastrocnemius
- B.
Soleus
- C.
Tibialis anterior
- D.
Tibialis posterior
- E.
Fibularis muscles
Correct Answer
C. Tibialis anteriorExplanation
The muscles that cause plantar flexion are the gastrocnemius, soleus, tibialis posterior, and fibularis muscles. The tibialis anterior is the only muscle listed that does not cause plantar flexion. Instead, it is responsible for dorsiflexion, which is the movement that lifts the foot upwards.Rate this question:
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- 37.
In walking, which two lower limb muscles keep the forward-swinging foot from dragging on the ground?
- A.
Pronator teres and popliteus
- B.
Flexor digitorum longus and popliteus
- C.
Adductor longus and abductor digiti minimi in foot
- D.
Gluteus medius and tibialis anterior
Correct Answer
D. Gluteus medius and tibialis anteriorExplanation
The gluteus medius and tibialis anterior muscles play a role in keeping the forward-swinging foot from dragging on the ground during walking. The gluteus medius, located in the hip, helps to stabilize the pelvis and prevent excessive hip drop, allowing for a smooth and efficient gait. The tibialis anterior, located in the front of the lower leg, is responsible for dorsiflexion of the foot, which lifts the toes and prevents them from dragging on the ground during the swing phase of walking.Rate this question:
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- 38.
Which criterion (or criteria) are used in naming the gluteus medius?
- A.
Relative size
- B.
Muscle location
- C.
Muscle shape
- D.
Action
- E.
Number of origins
Correct Answer(s)
A. Relative size
B. Muscle locationExplanation
The criteria used in naming the gluteus medius are relative size and muscle location. The term "gluteus" refers to the muscle group it belongs to, which is the gluteal muscles. The term "medius" indicates its relative size compared to other muscles in the same group, suggesting that it is located in the middle or intermediate position.Rate this question:
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- 39.
Which of the following is a large, deep muscle that protracts the scapula during punching?
- A.
Serratus anterior
- B.
Rhomboids
- C.
Levator scapulae
- D.
Subscapularis
Correct Answer
A. Serratus anteriorExplanation
The serratus anterior is a large, deep muscle that is responsible for protracting the scapula during punching. It is located on the lateral aspect of the rib cage and attaches to the scapula, allowing it to move forward and away from the spine. This muscle is important for stabilizing the scapula and providing the necessary movement for effective punching.Rate this question:
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- 40.
The connective tissue covering that encloses the sarcolemma of an individual muscle fiber is called the
- A.
Epimysium
- B.
Perimysium
- C.
Endomysium
- D.
Periosteum
Correct Answer
C. EndomysiumExplanation
The correct answer is endomysium. The endomysium is the connective tissue covering that surrounds and protects the sarcolemma, which is the cell membrane of a muscle fiber. It is the innermost layer of connective tissue and provides support and insulation for the individual muscle fiber. The epimysium, perimysium, and periosteum are also connective tissues, but they do not specifically enclose the sarcolemma of a muscle fiber.Rate this question:
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- 41.
A fascicle is a
- A.
Muscle
- B.
Bundle of muscle fibers enclosed by a connective tissue sheath
- C.
Bundle of myofibrils
- D.
Group of myofilaments
Correct Answer
B. Bundle of muscle fibers enclosed by a connective tissue sheathExplanation
A fascicle is a bundle of muscle fibers enclosed by a connective tissue sheath. This sheath, known as the perimysium, provides support and protection to the muscle fibers within the fascicle. The fascicle is a structural unit of a muscle and is responsible for transmitting force generated by the muscle fibers to produce movement.Rate this question:
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- 42.
Thick and thin myofilaments have different compositions. For each descriptive phrase, indicate whether the filament is thick or thin. (1) Contains actin
- A.
Thick
- B.
Thin
Correct Answer
B. ThinExplanation
The statement "Contains actin" indicates that the filament being described is thin. Actin is a protein that makes up the thin filaments in muscle cells. Thick filaments, on the other hand, are composed of the protein myosin. Since actin is mentioned, it implies that the filament being referred to is thin.Rate this question:
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- 43.
(2) Contains ATPases
- A.
Thick
- B.
Thin
Correct Answer
A. ThickExplanation
Thick filaments in muscle cells contain ATPases. ATPases are enzymes that hydrolyze ATP, releasing energy that is necessary for muscle contraction. These ATPases are found in the myosin heads of the thick filaments. When ATP is hydrolyzed, the energy released is used to power the sliding of the thick and thin filaments, leading to muscle contraction. Therefore, the correct answer is "Thick".Rate this question:
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- 44.
(3) attaches to the Z disc
- A.
Thick
- B.
Thin
Correct Answer
B. ThinExplanation
The statement "attaches to the Z disc" refers to the attachment of a structure to the Z disc. In the context of muscle anatomy, the Z disc is a protein structure that anchors the thin filaments. The thin filaments, composed of actin, are responsible for muscle contraction. Therefore, the correct answer is "thin" since the thin filaments attach to the Z disc.Rate this question:
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- 45.
(4) Contains myosin
- A.
Thick
- B.
Thin
Correct Answer
A. ThickExplanation
The correct answer is "thick." This is because myosin is a protein that is found in the thick filaments of muscle fibers. The thick filaments are responsible for generating force during muscle contraction. On the other hand, the thin filaments contain actin, another protein involved in muscle contraction. Therefore, the statement that the structure contains myosin indicates that it is referring to the thick filaments.Rate this question:
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- 46.
(5) Contains troponin
- A.
Thick
- B.
Thin
Correct Answer
B. ThinExplanation
The correct answer is "Thin" because thin filaments in muscle cells contain a protein called troponin. Troponin plays a crucial role in muscle contraction by regulating the interaction between actin and myosin filaments. It helps in the binding of calcium ions, which triggers the movement of the thin filaments and leads to muscle contraction. On the other hand, thick filaments are composed of myosin protein and are responsible for generating the force during muscle contraction.Rate this question:
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- 47.
(6) does not lie in the I band
- A.
Thick
- B.
Thin
Correct Answer
A. ThickExplanation
The given statement states that (6) does not lie in the I band. Since the options are "Thick" and "Thin," we can infer that the I band represents a region associated with thin filaments. Therefore, if (6) does not lie in the I band, it must be associated with thick filaments.Rate this question:
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- 48.
The function of the T tubules in muscle contraction is to
- A.
Make and store glycogen
- B.
Release Ca2+ into the cell interior and then pick it up again
- C.
Transmit the action potential deep into the muscle cells
- D.
Form proteins
Correct Answer
C. Transmit the action potential deep into the muscle cellsExplanation
The T tubules in muscle contraction are responsible for transmitting the action potential deep into the muscle cells. This allows for synchronized contraction of the entire muscle fiber. The action potential travels along the T tubules, triggering the release of calcium ions from the sarcoplasmic reticulum, which then initiates the sliding of the actin and myosin filaments, leading to muscle contraction. Therefore, the T tubules play a crucial role in the excitation-contraction coupling process in muscles.Rate this question:
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- 49.
The sites where the motor nerve impulse is transmitted from the nerve endings to the skeletal muscle cell membranes are the
- A.
Neuromuscular junctions
- B.
Sacromeres
- C.
Myofilaments
- D.
Z discs
Correct Answer
A. Neuromuscular junctionsExplanation
The correct answer is neuromuscular junctions. These junctions are the sites where the motor nerve impulse is transmitted from the nerve endings to the skeletal muscle cell membranes. At the neuromuscular junction, the nerve ending releases a chemical called acetylcholine, which binds to receptors on the muscle cell membrane, causing the muscle to contract. This communication between the nerve and muscle is essential for muscle movement and coordination. Sacromeres, myofilaments, and Z discs are all components of the muscle cell structure, but they are not directly involved in the transmission of nerve impulses.Rate this question:
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- 50.
Contraction elicited by a single brief stimulus is called a
- A.
Twitch
- B.
Wave summation
- C.
Multiple motor unit summation
- D.
Fused tetanus
Correct Answer
A. TwitchExplanation
A contraction elicited by a single brief stimulus is called a "twitch." This means that when a muscle receives a single stimulus, it contracts and then relaxes. It is a quick and isolated contraction that occurs in response to a single signal from the nervous system. This is in contrast to other options such as wave summation, multiple motor unit summation, and fused tetanus, which involve sustained or repeated contractions that are not elicited by a single brief stimulus.Rate this question:
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Mar 22, 2023Quiz Edited by
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Nov 10, 2010Quiz Created by
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