Question 1

Which of the following proteins is the main component of thick filaments?&#10;A) myosin&#10;B) sarcoplasm&#10;C) actin&#10;D) myofibril

Accepted Answer

Myosin is the main component of thick filaments in muscle cells.

Question 2

What is the anatomical name for the tube-like structures that are open to the surface of the sarcolemma and form a portion of a triad?&#10;A) cisternae&#10;B) myofibril&#10;C) sarcoplasmic reticulum&#10;D) T-tubules

Accepted Answer

T-tubules are the tube-like structures that are open to the surface of the sarcolemma and form a portion of a triad. The T-tubules play a crucial role in the process of muscle contraction by allowing the action potential to penetrate deep into the muscle fiber, triggering the release of calcium ions from the sarcoplasmic reticulum.

Question 3

Which of the following is a globular protein that binds to calcium?&#10;A) tropomyosin&#10;B) troponin&#10;C) actin&#10;D) myosin

Accepted Answer

Troponin is a globular protein that binds to calcium ions, which allows for the regulation of muscle contraction. Tropomyosin and actin are also involved in muscle contraction, but they do not directly bind to calcium ions. Myosin is a motor protein that interacts with actin to produce movement, but it does not bind to calcium.

Question 4

Which of the following is a double-stranded protein that blocks actin-binding sites?&#10;A) myosin&#10;B) DNA&#10;C) tropomyosin&#10;D) troponin

Accepted Answer

Tropomyosin is a double-stranded protein that blocks actin-binding sites in muscle cells, preventing myosin from binding and initiating muscle contraction. Myosin (A) is a motor protein that interacts with actin to generate force in muscle cells. DNA (B) is a hereditary material that contains genetic information, but it does not play a role in muscle contraction. Troponin (D) is a complex of three proteins that regulates tropomyosin's position on actin filaments in response to calcium ions, allowing myosin to bind and initiate muscle contraction. However, it is not itself a double-stranded protein that blocks actin-binding sites.

Question 5

What happens when a patient is poisoned by botulism?&#10;A) increased respiratory rate&#10;B) blurry, double vision&#10;C) constricted pupils&#10;D) increased acetylcholine release

Accepted Answer

One of the main symptoms of botulism poisoning is blurry, double vision, which is caused by the toxin affecting nerves involved in eye movement.

Answer: A, C, D are incorrect
 Botulism poisoning does not lead to an increased respiratory rate, constricted pupils, or increased acetylcholine release. In fact, it causes respiratory paralysis, dilated pupils, and decreased acetylcholine release.

Question 6

What structure of a sarcomere contains proteins that connect and stabilize thin filaments?&#10;A) Z line&#10;B) H band&#10;C) I band&#10;D) A band

Accepted Answer

The Z line is the structure of a sarcomere that contains proteins called alpha-actinin, which connect and stabilize thin filaments.

Question 7

What is the anatomical name for the combination of cisternae and a transverse tubule?&#10;A) sarcoplasmic reticulum&#10;B) sarcolemma&#10;C) triad&#10;D) Z line

Accepted Answer

The combination of cisternae (from the sarcoplasmic reticulum) and a transverse tubule is known as a triad.

Question 8

What is the name for embryonic muscle cells?&#10;A) myosins&#10;B) myoblasts&#10;C) myofibrils&#10;D) myofilaments

Accepted Answer

Myoblasts are embryonic cells that differentiate and give rise to muscle cells. Myosins are a type of protein found in muscle cells, myofibrils are tiny contractile fibers that make up muscle cells, and myofilaments are the even smaller components that make up myofibrils.

Question 9

Which of the following is both a protein and a structural component of thin filaments?&#10;A) actin&#10;B) myosin&#10;C) myofibrils&#10;D) T-tubules

Accepted Answer

Actin is a protein that makes up the majority of thin filaments in muscle cells. It plays a critical role in muscle contraction by interacting with myosin to produce the sliding effect of muscle contraction. Myosin is also a protein involved in muscle contraction, but it is a component of thick filaments rather than thin filaments. Myofibrils are the contractile units of muscle cells that contain the thin and thick filaments. T-tubules are invaginations of the plasma membrane that allow for the propagation of action potentials in muscle cells.

Question 10

What ion enters the muscle cell upon activation of the acetylcholine receptors?&#10;A) sodium&#10;B) calcium&#10;C) potassium&#10;D) chloride

Accepted Answer

Activation of acetylcholine receptors in the muscle cell leads to the influx of sodium ions, which triggers depolarization of the cell and ultimately leads to muscle contraction.

Question 11

What is the name of the area of the sarcolemma that is associated with the neuromuscular junction?&#10;A) junctional folds&#10;B) synaptic terminal&#10;C) synaptic cleft&#10;D) motor end plate

Accepted Answer

The answer of What is the name of the area...

Question 12

What structure contains proteins that stabilize the thin filaments?&#10;A) Z line&#10;B) M line&#10;C) A band&#10;D) I band

Accepted Answer

The answer of What structure contains proteins that stabilize the...

Question 13

What would most likely happen if there were a decrease in the number of acetylcholine receptors in an NMJ?&#10;A) decreased neurotransmitter release into the synaptic cleft&#10;B) increased sodium ion influx at the motor endplate&#10;C) decreased action potential generation at the motor endplate&#10;D) increased action potential generation at the motor endplate

Accepted Answer

The answer of What would most likely happen if there...

Question 14

What is the &#34;group name&#34; for a motor nerve fiber and all the muscle fibers it stimulates?&#10;A) motor end plate&#10;B) myasthenia gravis&#10;C) synaptic terminal&#10;D) motor unit

Accepted Answer

The answer of What is the &#34;group name&#34; for a...

Question 15

What is the cell membrane of a muscle cell called?&#10;A) sarcolemma&#10;B) sarcomere&#10;C) sarcoplasmic reticulum&#10;D) sarcoplasm

Accepted Answer

The answer of What is the cell membrane of a...

Question 16

The release of calcium ions from the sarcoplasmic reticulum in response to an action potential is known as ________.&#10;A) power stroke&#10;B) sliding filament theory&#10;C) tropomyosin&#10;D) excitation-contraction coupling

Accepted Answer

The answer of The release of calcium ions from the...

Question 17

What is it called when the myosin heads pivot and pull on the actin filaments?&#10;A) power stroke&#10;B) tropomyosin displacement&#10;C) action potential&#10;D) troponin

Accepted Answer

The answer of What is it called when the myosin...

Question 18

Which neurotransmitter is released at the neuromuscular junction?&#10;A) sodium&#10;B) acetylcholine&#10;C) glutamate&#10;D) acetylcholinesterase

Accepted Answer

The answer of Which neurotransmitter is released at the neuromuscular...

Question 19

Which structure stores calcium ions for release in the muscle cell?&#10;A) sarcolemma&#10;B) sarcomere&#10;C) sarcoplasm&#10;D) sarcoplasmic reticulum

Accepted Answer

The answer of Which structure stores calcium ions for release...

Question 20

What is the name for the region of the sarcomere that contains only thick filaments?&#10;A) Z line&#10;B) A band&#10;C) H band&#10;D) I band

Accepted Answer

The answer of What is the name for the region...

Deck 10: Introduction to Skeletal Muscle