Chapter 12 Practice Questions

Question 1

The cells of muscles are called muscle ______.

Answer 1

Fibers

Question 2

What is the principle purpose of the muscular system?

Answer 2

Create movement

Question 3

Select all of the following that are muscle tissue types:
• Rough
• Cardiac
• Skeletal
• Smooth
• Digestive

Answer 3

• Cardiac
• Skeletal
• Smooth

Question 4

The region where the end of an axon from a neuron comes into close contact with a muscle fiber is called a ______ junction.

Answer 4

Neuromuscular

Question 5

The main protein that is found in the thin filaments in myofibrils of muscle fibers, is called ______.

Answer 5

actin

Question 6

What permits rapid passing of a contraction between cardiac muscle fibers?

Answer 6

Intercalated disks

Question 7

Select all of the following that are components of a muscle fiber:
• Sacromere
• Sarcoplasmic reticulum
• Axon terminal
• Myofibril
• Sarcolemma

Answer 7

• Sacromere
• Sarcoplasmic reticulum
• Myofibril
• Sarcolemma

Question 8

Put the molecular events underpinning muscle contraction in order, beginning with the action that provides the required energy:
• ADP and phosphate are bound to myosin
• The myosin head bends as ADP and phosphate are released
• ATP is split by myosin release
• ATP is bound by myosin

Answer 8

1. ATP is split by myosin release
2. ADP and phosphate are bound to myosin
3. The myosin head bends as ADP and phosphate are released
4. ATP is bound by myosin

Question 9

Which of the following describe cramps?
A. Can occur when sleeping after a strenuous workout
B. Can occur in leg and foot after strenuous activity
C. Generally does not occur after or during strenuous activity
D. Strong, painful spasms

Answer 9

A. Can occur when sleeping after a strenuous workout
B. Can occur in leg and foot after strenuous activity
D. Strong, painful spasms

Question 10

Fascia is a type of connective tissue that surrounds the muscle. What is it called when it extends beyond the muscle?

Answer 10

Tendon

Question 11

In a myofibril, what is the distance from one Z line to the next?

Answer 11

Sacromere

Question 12

The main protein that is found in the thick filaments in the myofibrils is called ______.

Answer 12

Myosin

Question 13

How do the myosin-binding sites become exposed, allowing myosin to bind with actin?

Answer 13

When calcium is released from the sarcoplasmic reticulum, tropomyosin threads shift their position, exposing the myosin-binding sites

Question 14

What occurs during muscle contraction according to the sliding filament model?
• Myosin blocks binding sites to actin
• When the sarcomere lengthens the actin slide past the myosin
• Myosin filaments break down ATP
• Myosin heads form cross bridges towards the binding sites on sctin

Answer 14

• Myosin filaments break down ATP

* Myosin heads form cross bridges towards the binding sites on actin

Question 15

What are muscle fibers that fatigue quickly, are light in color, and contain little or no myoglobin?

Answer 15

Fast-twitch fibers

Question 16

Which of the following are the characteristics of fermentation in muscle contraction?
• Produces ATP
• Aerobic breakdown of glucose
• Does not require oxygen
• Results in buildup of lactate

Answer 16

• Produces ATP
• Does not require oxygen
• Results in buildup of lactate

Question 17

A muscle cell organelle that consist of a linear arrangement of sacromeres and contains both thick and thin filaments is called a ______.

Answer 17

Myofibril

Question 18

Which of the following is an example of antagonistic muscle action?
A. When the biceps flex the forearm, the triceps extend the forearm
B. When the biceps extend the forearm, the triceps extend the forearm
C. When the biceps flex the forearm, the triceps flex the forearm
D. When the biceps extend the forearm, muscles in the forearm resist the biceps

Answer 18

A. When the biceps flex the forearm, the triceps extend the forearm

Question 19

The ______ of a muscle is on a stationary bone and the ______ of a muscle is on a bone that moves.

Answer 19

Origin, insertion

Question 20

Select all of the following ways by which skeletal muscles protect the body.
• Reinforce and cushion joints
• Abdominal muscles protect internal organs
• Pad the skull
• Pad and protect bones
• Form a protective wall around the lungs

Answer 20

• Reinforce and cushion the joints
• Abdominal muscles protect internal organs
• Pad and protect the bones

Question 21

What is the main source of heat that raises body temperature?

Answer 21

Contraction of skeletal muscles

Question 22

What does the all-or-none law of muscle contraction state?

Answer 22

Muscle fibers will contract completely or not at all.

Question 23

Select all of the following relationships between the skeletal and muscle systems that produce body movement:
• Pressure exerted by skeletal muscle contraction helps squeeze tissue fluid into lymphatic capillaries
• Muscle contractions keep bones warm
• Contraction of jaw muscles and tongue allow you to grind food with the teeth
• Skeletal muscles contract and pull on bones
• Bones store calcium needed for muscle contraction

Answer 23

• Contraction of jaw muscles and tongue allow you to grind food with the teeth
• Skeletal muscles contract and pull on bones
• Bones store calcium needed for muscle contraction

Question 24

______ ______ is a broad term applied to a group of disorders characterized by a progressive degeneration and weakening of muscles.

Answer 24

Muscular dystrophy

Question 25

The arrangement of ______ within a muscle fiber gives skeletal muscle a striated appearance.

Answer 25

Myofilaments