Question 1

What is the function of striated muscles?​ 
A)control blood pressure and move the eyes and lung 
B)move nutrients through the digestive tract and move bones 
C)control the heart and skeletal muscles 
D)control blood pressure and move the heart

Accepted Answer

C

Question 2

________ is a protein that makes up the thin filaments of myofibril.​ 
A)Pectin 
B)Myosin 
C)Actin 
D)Sarcomere

Accepted Answer

Actin is a protein that forms the thin filaments in myofibrils, which are responsible for muscle contractions. Pectin is a type of carbohydrate found in plants, myosin is a protein that makes up the thick filaments in myofibrils, and sarcomere is the basic unit of muscle contraction.

Question 3

The arrival of an action potential in a muscle fiber causes​ 
A)calcium to enter the muscle fiber. 
B)calcium to be released by internal organelles. 
C)acetylcholine to enter the muscle fiber. 
D)acetylcholine to be released by internal organelles.

Accepted Answer

The arrival of an action potential in a muscle fiber causes calcium to be released by internal organelles called the sarcoplasmic reticulum. This calcium release triggers a series of events that ultimately leads to muscle contraction.

Question 4

The long strands of protein running the length of a muscle fiber are called​ 
A)sarcomeres. 
B)myofibrils. 
C)Z lines. 
D)troponins.

Accepted Answer

The long strands of protein running the length of a muscle fiber are called myofibrils. Sarcomeres are the contractile units of myofibrils, Z lines are the boundaries of Sarcomeres, and troponins are regulatory proteins involved in muscle contraction.

Question 5

Action potentials in muscle fibers​ 
A)do not occur. 
B)spread out in two directions on either side of a receptor site. 
C)travel in only one direction, from one end of a muscle fiber to the other. 
D)lead to multiple twitches in that fiber.

Accepted Answer

Action potentials in muscle fibers spread out in two directions from the point of initiation, typically at or near the middle of the fiber, ensuring that the contraction signal is propagated throughout the entire muscle fiber efficiently.

Question 6

The separation of actin molecules from myosin molecules requires​ 
A)calcium. 
B)sodium. 
C)acetylcholine. 
D)energy.

Accepted Answer

The separation of actin molecules from myosin molecules requires energy in the form of ATP hydrolysis. This allows the myosin head to detach from actin and return to its original conformation, ready for another cycle of contraction. Calcium, sodium, and acetylcholine are involved in the process of muscle contraction, but they do not directly cause the separation of actin and myosin.

Question 7

Slow-twitch muscle fibers are to _______ as fast-twitch muscle fibers are to _______.​ 
A)Ia: Ib 
B)IIa; Ia 
C)I; IIa & IIb 
D)IIb; IIa

Accepted Answer

Slow-twitch muscle fibers are classified as Type I, which are more efficient for endurance and aerobic activities. Fast-twitch muscle fibers are classified as Type II, which include subtypes IIa and IIb, and are more suited for short bursts of power and anaerobic activities.

Question 8

-The structure indicated by the number 3 in this image is  
A)myofibril. 
B)z-line. 
C)sarcomere. 
D)motor end plate.

Accepted Answer

The answer of 
-The structure indicated by the number 3...

Question 9

Nutrients are moved through the digestive tract by _________ muscle.​ 
A)smooth 
B)cardiac 
C)striated 
D)both smooth and striated

Accepted Answer

Smooth muscle is found throughout the digestive tract and is responsible for moving nutrients through the system. Cardiac muscle is only found in the heart, and striated muscle is mainly associated with movement and support of the skeleton. Therefore, the best choice is A) smooth muscle.

Question 10

A muscle relaxes after contracting when​ 
A)calcium is taken up by internal organelles. 
B)internal acetylcholine is broken apart by acetylcholinesterase. 
C)troponin is taken up by internal organelles. 
D)myosin and actin begin to interact.

Accepted Answer

Calcium is taken up by internal organelles, such as the sarcoplasmic reticulum, which leads to the cessation of muscle contraction and allows the muscle to relax.

Question 11

Rigor mortis,or the muscle stiffness present after death,results primarily from 
A)a drop in acetylcholine levels. 
B)a lack of energy needed to separate actin and myosin molecules. 
C)an increase in intracellular calcium concentrations. 
D)the breakdown of troponin molecules.

Accepted Answer

Rigor mortis occurs as a result of the lack of energy available to separate actin and myosin molecules, leading to a stiffening of the muscles. This process happens because the body is no longer producing ATP, which is required for muscle relaxation.

Question 12

Muscle fibers respond to​ 
A)serotonin. 
B)glutamate. 
C)dopamine. 
D)acetylcholine.

Accepted Answer

Muscle fibers respond to acetylcholine, a neurotransmitter released by motor neurons at the neuromuscular junction. This activates muscle contraction.

Question 13

Muscle fibers contract when Z lines move _________ and the sarcomeres _________.​ 
A)farther apart; stretch 
B)farther apart; shorten 
C)closer together; stretch 
D)closer together; shorten

Accepted Answer

Muscle fibers contract when the sarcomeres, which are the basic contractile units of muscle, shorten. In this process, the Z lines, which mark the boundaries of adjacent sarcomeres, move closer together.

Question 14

Slow-twitch fibers and fast-twitch fibers are both a type of​ 
A)myosin filament. 
B)actin filament. 
C)myofibril. 
D)sarcomere.

Accepted Answer

The answer of Slow-twitch fibers and fast-twitch fibers are both...

Question 15

In a resting muscle fiber,_________ is covered by a protein called _________.​ 
A)actin; troponin 
B)actin; calcium 
C)myosin; troponin 
D)myosin; calcium

Accepted Answer

In a resting muscle fiber, the thin filament made up of actin is covered by the protein troponin. Myosin is found on the thick filament and calcium ions are involved in muscle contraction, but neither of these are covering actin in a resting muscle cell.

Question 16

Single segments of a myofibril are called​ 
A)sarcomeres. 
B)twitches. 
C)Z lines. 
D)troponins.

Accepted Answer

Single segments of a myofibril are called sarcomeres.

Question 17

A Z line is ​ 
A)a segment of myofibril. 
B)a type of muscle fiber. 
C)the boundary of a sarcomere. 
D)the path of a muscular action potential.

Accepted Answer

The Z line is the boundary of a sarcomere, which is the basic unit of a muscle fiber. It defines the beginning and end of each sarcomere and helps to anchor the actin filaments in place. The other choices are incorrect as a Z line is not a segment of a myofibril, type of muscle fiber, or the path of a muscular action potential.

Question 18

One major difference between striated and smooth muscles is that​ 
A)smooth muscles move the voluntary system and striated muscles move automatic systems. 
B)striated muscles are responsible for fast twitch and smooth muscles are responsible for slow twitch. 
C)striated muscles move mostly voluntary systems while smooth muscles move involuntary, automatic systems. 
D)smooth muscles are made up of myofibrils and striated muscle is made up of only sarcomeres.

Accepted Answer

Striated muscles, also known as skeletal muscles, control voluntary movements like walking, jumping, and lifting. Smooth muscles, on the other hand, control involuntary movements like digestion and breathing. Therefore, striated muscles move mostly voluntary systems while smooth muscles move involuntary, automatic systems. Option A is incorrect because smooth muscles are not responsible for moving the voluntary system. Option B is incorrect because twitch speed does not differentiate between striated and smooth muscles. Option D is incorrect because both striated and smooth muscles contain actin and myosin fibers.

Question 19

The lungs are moved by _________ muscle​ 
A)smooth 
B)cardiac 
C)striated 
D)both smooth and striated

Accepted Answer

The lungs are moved by the diaphragm muscle, which is a striated muscle. Smooth muscle is found in the walls of internal organs like the intestine, and cardiac muscle only makes up the heart.

Question 20

What causes muscles to twitch? 
A)depolarization of the muscle fiber produced by an influx of sodium ions 
B)depolarization of the muscle fiber produced by an influx of potassium ions 
C) hyperpolarization of the muscle fiber produced by an influx of calcium ions 
D)hyperpolarization of the muscle fiber produced by an outflow of potassium ions

Accepted Answer

Muscles twitch due to depolarization of the muscle fiber produced by an influx of sodium ions. This can be caused by various reasons, such as nerve impulses, muscle fatigue, electrolyte imbalances, or caffeine intake.

Quiz 8: Movement

What is the function of striated muscles?

________ is a protein that makes up the thin filaments of myofibril.

The arrival of an action potential in a muscle fiber causes

The long strands of protein running the length of a muscle fiber are called

Action potentials in muscle fibers

The separation of actin molecules from myosin molecules requires

Slow-twitch muscle fibers are to _ as fast-twitch muscle fibers are to _.

-The structure indicated by the number 3 in this image is

Nutrients are moved through the digestive tract by _________ muscle.

A muscle relaxes after contracting when

Rigor mortis,or the muscle stiffness present after death,results primarily from

Muscle fibers respond to

Muscle fibers contract when Z lines move _ and the sarcomeres _.

Slow-twitch fibers and fast-twitch fibers are both a type of

In a resting muscle fiber,_ is covered by a protein called _.

Single segments of a myofibril are called

A Z line is

One major difference between striated and smooth muscles is that

The lungs are moved by _________ muscle

What causes muscles to twitch?

Quiz 8: Movement

What is the function of striated muscles?​

________ is a protein that makes up the thin filaments of myofibril.​

The arrival of an action potential in a muscle fiber causes​

The long strands of protein running the length of a muscle fiber are called​

Action potentials in muscle fibers​

The separation of actin molecules from myosin molecules requires​

Slow-twitch muscle fibers are to _______ as fast-twitch muscle fibers are to _______.​

-The structure indicated by the number 3 in this image is

Nutrients are moved through the digestive tract by _________ muscle.​

A muscle relaxes after contracting when​