Muscular Tissue Quiz

Front 1

Which muscle(s) can contract without the need for nervous stimulation?

Back 1

smooth and cardiac muscle

Front 2

The term for shortening of a muscle while maintaining constant tension is

Back 2

isotonic contraction

Front 3

Release of ACh

Back 3

increases permeability of the sarcolemma

Front 4

Which of the following best describes the resting membrane potential (RMP)?
A) The extracellular environment is negatively charged
B)The intracellular environment is negatively charged
C)It has a voltage of about +75 mV
D)It depends on the muscle fiber absorbing potassium ions from the ECF
E)The intracellular environment has more positively charged sodium

Back 4

B) The intracellular environment is negatively charged

Front 5

What is the purpose of the triad?

Back 5

The triad allows for Ca2+ release when a muscle fiber is excited

Front 6

Which of the following individuals would have more mitochondria in his skeletal muscle?
A)a 22-year-old football player
B)a newborn
C)a model on a reduced-calorie diet
D)a long-term hospice patient
E)a 50-year-old sedentary computer programmer

Back 6

A)a 22-year-old football player

Front 7

Loss of muscle mass from lack of activity is termed

Back 7

atrophy

Front 8

Which of the following is very important for muscle to continue contraction during anaerobic respiration?
A)protease
B)acid phosphatase
C)cholinesterase inhibitors
D)myokinase
E)acetylcholinesterase

Back 8

D) myokinase

Front 9

Which of the following has the largest mitochondria?
A)cardiac muscle
B)slow oxidative fibers
C)fast glycolytic fibers
D)intermediate fibers
E)smooth muscle

Back 9

A)cardiac muscle

Front 10

The triads of a muscle fiber consist of what?

Back 10

two terminal cisternae and one T tubule.

Front 11

Collagen is...
A)impermeable
B)expendable
C)elastic
D)contractile
E)excitable

Back 11

C)elastic

Front 12

A volleyball player depends on the gastrocnemius muscles for plantar flexion, whereas a marathon runner depends more on the soleus muscles for the same action. This is because the soleus muscles

Back 12

make more use of aerobic respiration.

Front 13

In skeletal muscle, alternating light and dark bands are termed

Back 13

striations

Front 14

Which of the following is not a purpose of the excess postexercise oxygen consumption in muscle?

Back 14

To neutralize carbon dioxide buildup

Front 15

Duing muscle contraction, a single myosin head consumes ATP at a rate of about

Back 15

9ATP per second

Front 16

The minimum stimulus needed to cause muscle contraction is called

Back 16

The threshold

Front 17

To stimulate muscle contraction, acetylcholine is released from the ___

Back 17

Synaptic knob

Front 18

. As you are lifting a box someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must

Back 18

Recruit more muscle fibers.

Front 19

protein that acts as a calcium receptor in skeletal muscle is

Back 19

troponin

Front 20

A skeletal muscle generates the greatest tension when it is

Back 20

In a state of treppe

Front 21

Which of the following is not a purpose of the excess postexercise oxygen consumption in muscle?

Back 21

to neutralize carbon dioxide buildup

Front 22

Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?

Back 22

skeletal muscle

Front 23

Aerobic respiration produces approximately _____ more ATPs per glucose molecule than glycolysis does.

Back 23

36

Front 24

Creatine kinase

Back 24

catalyzes the transfer of phosphate from CP to ADP.

Front 25

A myofilament that flanks a thick filament and anchors it to a Z disc is called

Back 25

an elastic filament.

Front 26

Athletes who train at high altitudes increase their red blood cell count and thus increase their oxygen supply during exercise. Increased oxygen supply results in

Back 26

longer aerobic respiration.

Front 27

Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. These drugs

Back 27

prevent calcium from entering smooth muscle, thus allowing the muscle to relax

Front 28

The sarcolemma of a resting muscle fiber is most permeable to

Back 28

potassium

Front 29

Which of the following is not a characteristic of a muscle cell?

Back 29

plasticity

Front 30

The training regimen of a competitive weight lifter is designed partly to

Back 30

increase the average number of myofibrils per muscle fiber.

Front 31

The contraction strength of smooth muscle is relatively independent of its resting length partly because

Back 31

it does not have Z discs.

Front 32

The purpose of varicosities in muscle physiology is

Back 32

to release norepinephrine.

Front 33

Helps maintain blood pressure

Back 33

Smooth muscle

Front 34

Squeezes or propels substances (i.e., food, feces) through organs

Back 34

Smooth muscle

Front 35

skeletal muscle

Back 35

cell: very long and cylindrical, extends length of muscle fasciculi
nucleus: multiple, peripherally located
striated, voluntary, incapable of spontaneous contraction

Front 36

smooth muscle

Back 36

cell: spindle shaped
nucleus: single centrally located
nonstriated, involuntary, sometimes capable of spontaneous contraction

Front 37

cardiac muscle

Back 37

cell: cylindrical and branched
nucleus: single centrally located
striated, involuntary, capable of spontaneous contractions

Front 38

Epimysium

Back 38

an overcoat of dense collagenous connective tissue that surrounds the entire muscle

Front 39

Perimysium

Back 39

fibrous connective tissue that surrounds fascicles

Front 40

Endomysium

Back 40

fine sheath of connective tissue composed of reticular fibers surrounding each muscle fiber

Front 41

Actin

Back 41

(thin) myofilaments consist of two helical polymer strands of F actin (composed of G actin), tropomyosin, and troponin

Front 42

G actin

Back 42

contains the active sites to which myosin heads attach during contraction

Front 43

regulatory subunits bound to actin

Back 43

Tropomyosin and troponin

Front 44

Myosin molecules

Back 44

-A head with an ATPase, which breaks down ATP
-A hinge region, which enables the head to move
-A rod

Front 45

cross-bridge

Back 45

formed when a myosin head binds to the active site on G actin

Front 46

the smallest contractile unit of a muscle

Back 46

sacromere

Front 47

Z disks

Back 47

a coin-shaped sheet of proteins (connectins) that anchors the thin filaments and connects myofibrils to one another

Front 48

how many actin myofilaments surround a myosin myofilament?

Back 48

6

Front 49

M lines

Back 49

appear darker due to the presence of the protein desmin

Front 50

The nervous system stimulates muscles to contract through electric signals called

Back 50

action potentials

Front 51

in a resting cell, the charge on the inside of the plasma membrane is

Back 51

negative

Front 52

action potential

Back 52

a reversal of the resting membrane potential so that the inside of the plasma membrane becomes positive

Front 53

Contains ACh receptors

Back 53

Motor end plate of a muscle

Front 54

Contain the neurotransmitter acetylcholine (ACh)

Back 54

Axonal endings

Front 55

The enzyme acetylcholinesterase removes acetylcholine from the synaptic cleft by

Back 55

breaking it down into acetic acid and choline

Front 56

Sarcoplasmic reticulum (SR)

Back 56

an elaborate, smooth endoplasmic reticulum that mostly runs longitudinal and surrounds each myofibril

Front 57

Functions in the regulation of intracellular calcium levels

Back 57

Sarcoplasmic reticulum

Front 58

The contraction of a muscle as a result of one or more muscle fibers contracting

Back 58

muscle twitch

Front 59

Has lag, contraction, and relaxation phases

Back 59

muscle twitch

Front 60

Stimulus of increasing frequency increase the force of contraction

Back 60

multiple-wave summation

Front 61

stimuli of increasing strength result in graded contractions of increased force as more motor units are recruited

Back 61

multiple motor unit summation