Muscle Fibers

Skeletal muscles consist of numerous _____________ that contain a bundle of _______________ which are composed of repeating contractile units called _____________?

• muscle fibers, sarcomeres, myofibrils

• sarcomeres, muscle fibers, myofibrils

• sarcomeres, myofibrils, muscle fibers

• muscle fibers, myofibrils, sarcomeres

The thin filament composed of protein in a myofibril is called?

• Actin

• Myosin

The property of all muscles that can be defined as the muscle tissue having a electric gradient which can reverse when stimulated is?

• Excitability

• Contraction

• Elongate

The type of muscle that is voluntary and is composed of muscle fibers that are bound together in parallel bundles and that is usually described as striated is called?

• Smooth

• Skeletal

• Cardiac

Which skeletal muscle fiber type is known for being fatigue resistant?

• Type 2B

• Type 2A

• Type 2X

• Type 1

Which muscle fiber type is first to be recruited during muscle activity?

• Type 2A

• Type 2B

• Type 1

• Type 2X

myosin

a

b

c

myosin

actin

Z line

Type 2A muscle fibers are known for being:

• Intermediate twitch

• Slow twitch

• Fast oxidative

• Fast glycolytic

Slow oxidative muscle fibers are best suited for endurance activities, such as long distance running, cycling, or rowing.

• running a marathon

• hitting a baseball

• lifting heavy weights at the gym

• running a 100-yard dash

What is the main source of energy storage in Type 1 muscle fibers?

• Triglycerides

• Glucose

• ATP

• Glycogen