Anatomy - Chapter 9

Front 1

The stimulus above which no stronger contraction can be elicited, because all motor units are firing in the muscle.

Back 1

Maximal stimulus

Front 2

The phenomenon in which the contraction strength of a muscle increases, due to increased Ca2+ availability and enzyme efficiency during the warm-up.

Back 2

Treppe

Front 3

Continued sustained smooth contraction due to rapid stimulation.

Back 3

Tetanus

Front 4

The situation in which contractions become stronger due to stimulation before complete relaxation occurs.

Back 4

Wave summation

Front 5

How a smooth increase in muscle force is produced.

Back 5

Multiple motor unit summation

Front 6

A sarcomere is the distance between two ________.

Back 6

Z discs

Front 7

The ________ contains only the actin filaments.

Back 7

I Band

Front 8

The thicker filaments are the________ filaments.

Back 8

Myosin

Front 9

Both actin and myosin are found in the ________.

Back 9

A Band

Front 10

The myosin filaments are located in the ________.

Back 10

A Band

Front 11

Serves as the actual ʺtriggerʺ for muscle contraction by removing the inhibition of the troponin molecules.

Back 11

Calcium Ions

Front 12

A neurotransmitter released at motor end plates by the axon terminals.

Back 12

Acetylcholine

Front 13

A metabolic pathway that provides for a large amount of ATP per glucose because oxygen is used. Products are water and carbon dioxide and ATP.

Back 13

Aerobic Respiration

Front 14

Normally stored in the terminal cisternae of the sarcoplasmic reticulum.

Back 14

Calcium Ions

Front 15

Used to convert ADP to ATP by transfer of a high-energy phosphate group. A reserve high-energy compound.

Back 15

Creatine Phosphate

Front 16

Destroys Ach.

Back 16

Acetlycholinesterase

Front 17

True/False: Once a motor neuron has fired, all the muscle fibers in a muscle contract.

Back 17

False

Front 18

True/False: The thin filaments (actin) contain a polypeptide subunit G actin that bear active sites for myosin attachment.

Back 18

True

Front 19

True/False: The force of muscle contraction is controlled by multiple motor unit summation or recruitment.

Back 19

True

Front 20

True/False: Eccentric contractions are more forceful than concentric contractions.

Back 20

True

Front 21

True/False: A motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate.

Back 21

False

Front 22

True/False: Peristalsis is characteristic of smooth muscle.

Back 22

True

Front 23

True/False: A contraction in which the muscle does not shorten but its tension increases is called isometric.

Back 23

True

Front 24

True/False: During isotonic contraction, the heavier the load, the faster the velocity of contraction.

Back 24

False

Front 25

True/False: During isometric contraction, the energy used appears as movement.

Back 25

False

Front 26

True/False: One of the important functions of skeletal muscle contraction is production of heat.

Back 26

True

Front 27

True/False: Oxygen debt refers to the oxygen required to make creatine phosphate.

Back 27

False

Front 28

True/False: Muscle contraction will always promote movement of body parts regardless of how they are attached.

Back 28

False

Front 29

True/False: Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.

Back 29

True

Front 30

True/False: Whereas skeletal muscle cells are electrically coupled, smooth muscle cells appear to be chemically coupled by gap junctions.

Back 30

False

Front 31

True/False: Single-unit smooth muscle is found in the intestines.

Back 31

True

Front 32

True/False: A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.

Back 32

True

Front 33

True/False: The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.

Back 33

True

Front 34

True/False: When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length.

Back 34

True

Front 35

True/False: The more slowly a skeletal muscle is stimulated, the greater its exerted force becomes.

Back 35

False

Front 36

True/False: Contractures are a result of a total lack of ATP.

Back 36

True

Front 37

True/False: Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions.

Back 37

True

Front 38

True/False: Recruitment is an option in a single-unit smooth muscle cell.

Back 38

False

Front 39

With muscular dystrophy ________.

Back 39

Muscle fibers degenerate and atrophy.

Front 40

Which muscle cells have the greatest ability to regenerate?

Back 40

Smooth

Front 41

Most muscles contain ________.

Back 41

A mixture of fiber types

Front 42

Fatigued muscle cells that recover rapidly are the products of ________.

Back 42

Intense exercise of short duration

Front 43

The strongest muscle contractions are normally achieved by ________.

Back 43

Increasing the stimulation up to the maximal stimulus

Front 44

Which of the following would be recruited later in muscle stimulation when contractile strength increases?

Back 44

Motor units with larger, less excitable neurons

Front 45

Which of the following is not a usual result of resistance exercise?

Back 45

Increase in the number of muscle cells

Front 46

In skeletal muscle contraction, calcium apparently acts to ________.

Back 46

Remove the blocking action of tropomyosin

Front 47

Calcium ions bind to the ________ molecule in skeletal muscle cells.

Back 47

Troponin

Front 48

Myoglobin ________.

Back 48

Stores oxygen in muscle cells

Front 49

An elaborate network of membranes in skeletal muscle cells that functions in calcium storage
is the ________.

Back 49

Sarcoplasmic recticulum

Front 50

A sarcomere is ________.

Back 50

The area between two Z discs

Front 51

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the events of excitation -contraction coupling occur.

Back 51

Latent

Front 52

Creatine phosphate functions in the muscle cell by ________.

Back 52

Storing energy that will be transferred to ADP to resynthesize ATP

Front 53

After nervous stimulation of the muscle cell has ceased, the calcium ________.

Back 53

Level in the cytoplasm drops

Front 54

The major function of the sarcoplasmic reticulum in muscle contraction is to ________.

Back 54

Regulate intracellular calcium concentration

Front 55

The striations of a skeletal muscle cell are produced, for the most part, by ________.

Back 55

The arrangement of myofilaments

Front 56

Which of the following are composed of myosin?

Back 56

Thick filaments

Front 57

During muscle contraction, myosin cross bridges attach to which active sites?

Back 57

Actin filaments

Front 58

Which of the following surrounds the individual muscle cell?

Back 58

Endomysium

Front 59

Smooth muscles that act like skeletal muscles but are controlled by autonomic nerves and hormones are ________.

Back 59

Multi-unit muscles

Front 60

Rigor mortis occurs because ________.

Back 60

No ATP is available to release attached actin and myosin molecules

Front 61

Which of the following does not act as a stimulus to initiate a muscle contraction?

A) hormonal activity B) neurotransmitters
C) a change in the pH of a muscle D) a change of temperature

Back 61

A change in temperature

Front 62

The term aponeurosis refers to ________.

Back 62

A sheetlike indirect attachment to a skeletal element

Front 63

The oxygen-binding protein found in muscle cells is ________.

Back 63

Myoglobin

Front 64

The contractile units of skeletal muscles are ________.

Back 64

Myofibrils

Front 65

The site of calcium regulation in the smooth muscle cell is ________.

Back 65

Calmodulin

Front 66

One functional unit of a skeletal muscle is ________.

Back 66

A sarcomere

Front 67

The functional role of the T tubules is to ________.

Back 67

Enhance cellular communication during muscle contraction

Front 68

The role of calcium ions in muscle contraction is to ________.

Back 68

Bind to regulatory sites on troponin, changing the configuration

Front 69

The warm-up period required of athletes in order to bring their muscles to peak performance is called ________.

Back 69

Wave summation

Front 70

) The main effect of the warm-up period of athletes, as the muscle contractions increase instrength, is to ________.

Back 70

Enhance the availability of calcium and the efficiency of enzyme systems

Front 71

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.

Back 71

Lactic Acid

Front 72

When a muscle is unable to respond to stimuli temporarily, it is in which of the following
periods?

Back 72

Refractory period

Front 73

In an isotonic contraction, the muscle ________.

Back 73

Changes in length and moves the ʺloadʺ

Front 74

The muscle cell membrane is called the ________.

Back 74

Sarcolemma

Front 75

Smooth muscle is significantly different from striated muscle in several ways. Which of the
following is true?

Back 75

Smooth muscle contracts in a twisting way.

Front 76

The mechanism of contraction in smooth muscle is different from skeletal muscle in that
________.

Back 76

The site of calcium regulation differs

Front 77

The cells of single-unit visceral muscle ________.

Back 77

Exhibit spontaneous action potentials

Front 78

Which of the following statements is not true concerning developmental aspects of muscle?

A) There is no biological basis for the difference in strength between women and men.
B) Skeletal muscle is derived from mesoderm.
C) Skeletal muscle develops from somites.
D) Most muscle tissues develop from myoblasts.

Back 78

There is no biological basis for the difference in strength between women and men.

Front 79

Which of the following is true about smooth muscle contraction?

A) Certain smooth muscle cells can actually divide to increase their numbers.
B) Smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any connective tissue elements.
C) Smooth muscle cannot stretch as much as skeletal muscle.
D) Smooth muscle has well-developed T tubules at the site of invagination.

Back 79

Certain smooth muscle cells can actually divide to increase their numbers

Front 80

Smooth muscle is characterized by all of the following except ________.

Back 80

There are more thick filaments than thin filaments

Front 81

Muscle tissue has all of the following properties except ________.

Back 81

Secretion

Front 82

The giant protein titin maintains the organization of the ________ assisting in muscle stretching.

Back 82

A Band

Front 83

Which of the following statements is true?
A) Cardiac muscle cells have many nuclei.
B) Smooth muscle cells have T tubules.
C) Striated muscle cells are long and cylindrical with many nuclei.
D) Cardiac muscle cells are found in the heart and large blood vessels.

Back 83

Striated muscle cells are long and cylindrical with many nuclei.

Front 84

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________.

Back 84

Glycolysis

Front 85

Muscle tone is ________.

Back 85

A state of sustained partial contraction

Front 86

The sliding filament model of contraction involves ________.

Back 86

Actin and myosin sliding past each other and partially overlap

Front 87

After nervous stimulation stops, ACh in the synaptic cleft is prevented from continuing stimulation of contraction by ________.

Back 87

Acetylcholinesterase destroying the ACh

Front 88

Which of the following is most accurate?

A) Muscle tension remains relatively constant during isotonic contraction.
B) T-tubles may be sliding during isotonic contraction.
C) The I band lenghtens during isotonic contraction.
D) Myofilaments slide during isometric contractions.

Back 88

Muscle tension remains relatively constant during isotonic contraction.

Front 89

The most distinguishing characteristic of muscle tissue is ________.

Back 89

The ability to transform chemical energy into mechanical energy

Front 90

Three discrete types of muscle fibers are identified on the basis of their size, speed, and
endurance. Which of the following athletic endeavors best represents the use of red fibers?

Back 90

A long, relaxing swim

Front 91

Of the following muscle types, which has only one nucleus, no sarcomeres, and rare gap
junctions?

Back 91

Multiunit smooth muscle

Front 92

Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped ________.

Back 92

No muscle tension could be generated

Front 93

An individual has just ingested a chemical that binds irreversibly to the ACh receptors in the sarcolemma. By itself it does not alter membrane potential, yet prevents normal neurotransmitter binding. Ignoring the effects on any other system, the consequence to skeletal
muscle would be ________.

Back 93

no contraction at all by nervous mechanisms, but Contraction if stimulated by an external electrode