Question 1

Figure 10-2 Muscle Contractions
 
Use Figure 10-2 to answer the following questions:
-What is the contraction in graph (a) called?

Accepted Answer

The answer of Figure 10-2 Muscle Contractions
 
Use Figure 10-2...

Question 2

The point in a muscle twitch when the troponin is bound to calcium is called the

Accepted Answer

During muscle twitch, the troponin complex binds to calcium ions, which then allows the myosin and actin filaments to slide past each other, leading to muscle contraction. Therefore, the point in a muscle twitch when the troponin is bound to calcium is called the contraction phase.

Question 3

During the time when the action potential moves through the sarcolemma a muscle twitch is in

Accepted Answer

The latent period is the time between the application of a stimulus and the beginning of a muscle contraction, during which the action potential moves through the sarcolemma.

Question 4

A muscle produces its highest tension when in complete

Accepted Answer

Tetanus refers to sustained muscular contraction without relaxations, which produces the highest tension a muscle can generate. Recovery, treppe, and wave summation all refer to muscle contractions, but they do not produce the highest tension possible. Aerobic metabolism refers to energy production within the muscle, but it does not directly impact tension production.

Question 5

The type of contraction in which the muscle fibers do not shorten is called

Accepted Answer

Isometric contractions occur when the muscle generates force without changing its length. The muscle fiber tension increases, but the muscle does not shorten or lengthen. Tetany refers to a sustained muscle contraction, treppe is a phenomenon in which the force of muscle contraction increases in response to repeated stimulation, concentric contractions involve shortening of the muscle fibers, and isotonic contractions involve movement and shortening of the muscle fibers.

Question 6

Put the following events of the contraction cycle in the order in which they occur.
1) Cross-bridge detachment
2) Cross-bridge formation
3) Active site exposure
4) Myosin reactivation
5) Calcium ions bind troponin
6) Myosin head pivoting

Accepted Answer

The order of events in the contraction cycle is as follows:
1) Calcium ions bind troponin, causing a conformational change in tropomyosin, which exposes the active sites on actin.
2) Myosin heads bind to the exposed active sites on actin, forming cross-bridges.
3) The energy released from ATP hydrolysis causes the myosin head to pivot, moving the actin filament toward the center of the sarcomere.
4) Cross-bridge detachment occurs when a new ATP molecule binds to the myosin head, causing it to release from actin.
5) Myosin reactivation occurs when the energy from ATP hydrolysis is used to reposition the myosin head back into its high-energy state.
Therefore, the correct order of events is 5,3,2,6,1,4, and the best choice is C.

Question 7

A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in

Accepted Answer

In incomplete tetanus, the muscle produces almost peak tension during rapid cycles of contraction and relaxation, with some relaxation occurring between contractions.

Question 8

Figure 10-2 Muscle Contractions
 
Use Figure 10-2 to answer the following questions:
-What is thought to happen in a muscle during the response shown in graph (a)?

Accepted Answer

Graph (a) shows the gradual increase in calcium ion concentration in the sarcoplasm, which is thought to happen during muscle contraction.

Question 9

Put the following events of excitation-contraction coupling in the order in which they occur.
1) Excitation
2) Sarcomere shortening
3) Generation of muscle tension
4) Neural control
5) Contraction cycle begins
6) Release of calcium ions

Accepted Answer

The correct sequence for excitation-contraction coupling starts with neural control (4), followed by excitation of the muscle fiber (1), then the release of calcium ions (6), which triggers the contraction cycle to begin (5). This leads to sarcomere shortening (2) and ultimately results in the generation of muscle tension (3).

Question 10

A single motor neuron together with all the muscle fibers it innervates is called a(n)

Accepted Answer

A motor unit consists of a single motor neuron and all the muscle fibers it innervates. The other options are not correct - an end foot is not a recognized term in neuromuscular physiology, an end plate refers specifically to the neuromuscular junction, dermatomes refer to the region of skin innervated by a single spinal nerve, and myotomes refer to the muscle groups innervated by a single spinal nerve.

Question 11

Figure 10-2 Muscle Contractions
 
Use Figure 10-2 to answer the following questions:
-What is the contraction in graph (d) called?

Accepted Answer

The contraction in graph (d) is called complete tetanus, as it shows a sustained contraction without any relaxation between the stimuli. This is achieved through rapid sequential stimulation of muscle fibers, which is known as tetanus.

Question 12

The increase in muscle tension that is produced by increasing the number of active motor units is called

Accepted Answer

The increase in muscle tension that is produced by increasing the number of active motor units is called recruitment. In recruitment, more motor units are activated as the intensity of the stimulus increases, leading to an increase in muscle tension.

Question 13

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contractionoccurs. This addition of one twitch to another is called

Accepted Answer

Wave summation describes the addition of one twitch to another when a second stimulus arrives before the relaxation phase has ended. This results in a more powerful contraction than a single twitch. Incomplete tetanus occurs when there is partial relaxation between contractions, while complete tetanus is a sustained contraction with no relaxation. Treppe describes the phenomenon of progressively stronger contractions due to increasing Ca2+ availability, and recruitment refers to the activation of additional motor units to increase muscle force.

Question 14

Detachment of myosin cross-bridges occurs during the

Accepted Answer

Myosin cross-bridges detach during the relaxation phase of muscle contraction. This occurs when the nerve impulse ends and calcium ions are actively transported back into the sarcoplasmic reticulum, causing the tropomyosin to cover the binding sites on actin filaments and leading to detachment of the myosin cross-bridges from the actin filament.

Question 15

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This state of maximum tension is called

Accepted Answer

Complete tetanus refers to the state of maximum tension that occurs when a muscle is stimulated repeatedly at a high rate without allowing for any relaxation periods. This state is characterized by sustained contractions of the muscle fibers and a plateau in the amount of tension generated.

Question 16

Figure 10-2 Muscle Contractions
 
Use Figure 10-2 to answer the following questions:
-To produce a contraction similar to the one in graph (b), the muscle

Accepted Answer

Graph (b) shows a sustained contraction of muscle fibers, which is achieved by multiple stimuli being applied before the muscle has fully relaxed. This is known as tetanus.

Question 17

Put the following events of the neuromuscular junction in the order in which they occur.
1) Action potential is propagated in the sarcolemma.
2) Acetylcholine binds to ligand gated sodium channels.
3) Action potential arrives at the neuromuscular junction.
4) Vesicles full of acetylcholine are stored at the axon terminal.
5) Acetylcholine is released into the synaptic cleft.

Accepted Answer

The correct sequence for the events at the neuromuscular junction starts with vesicles full of acetylcholine being stored at the axon terminal (4), followed by the arrival of an action potential at the neuromuscular junction (3). This triggers the release of acetylcholine into the synaptic cleft (5). Acetylcholine then binds to ligand-gated sodium channels on the muscle cell membrane (2), which leads to the propagation of an action potential in the sarcolemma (1).

Question 18

The rapid rise and fall in force produced by a muscle fiber after a single action potential is a(n)

Accepted Answer

The rapid rise and fall in force produced by a muscle fiber after a single action potential is called a twitch. A twitch is a brief and sudden contraction of a muscle fiber in response to a single action potential. It consists of three phases: the latent period, the contraction phase, and the relaxation phase.

Question 19

Figure 10-2 Muscle Contractions
 
Use Figure 10-2 to answer the following questions:
-Why is there partial relaxation in graph (c)?

Accepted Answer

Partial relaxation occurs when the nerve stimulation frequency is below maximum, allowing some relaxation between contractions.

Question 20

A single contraction-relaxation cycle in a muscle fiber produces a(n)

Accepted Answer

A single contraction-relaxation cycle in a muscle fiber is known as a twitch. This is a brief and rapid contraction and relaxation of the muscle fiber that is stimulated by a single action potential.

Quiz 10: Muscle Tissue

Figure 10-2 Muscle Contractions Use Figure 10-2 to answer the following questions: -What is the contraction in graph (a) called?

The point in a muscle twitch when the troponin is bound to calcium is called the

During the time when the action potential moves through the sarcolemma a muscle twitch is in

A muscle produces its highest tension when in complete

The type of contraction in which the muscle fibers do not shorten is called

Put the following events of the contraction cycle in the order in which they occur. 1) Cross-bridge detachment 2) Cross-bridge formation 3) Active site exposure 4) Myosin reactivation 5) Calcium ions bind troponin 6) Myosin head pivoting

A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in

Figure 10-2 Muscle Contractions Use Figure 10-2 to answer the following questions: -What is thought to happen in a muscle during the response shown in graph (a) ?

Put the following events of excitation-contraction coupling in the order in which they occur. 1) Excitation 2) Sarcomere shortening 3) Generation of muscle tension 4) Neural control 5) Contraction cycle begins 6) Release of calcium ions