Chapter 9: End of Chapter Questions

Pennate muscle arrangements are fibers that (select all that apply):

-Attach obliquely to its tendon -Create a featherlike arrangement -Are better able to produce force

Type IIa

-Color is red/white. -Fatigue resistance is intermediate/low.

Type IIb

-Color is white and fiber size is large. -Power output is high.

Which of the following are phases in the stretch-shortening cycle? Choose all that apply.

-Concentric phase -Eccentric phase -Amortization phase

Type I

-Fiber size is small. -Mitochondria and capillary density is high.

Which of the following methods of training have been shown to transition Type IIb to Type IIa fibers? Select all that apply.

-High intensity resistance training -High intensity aerobic endurance

Skeletal muscle adapts to anaerobic training primarily by:

-Increasing its size -Facilitating fiber type transitions -Enhancing its biochemical and ultra-structural components

The benefits of exercise include which of the following? Select all that apply.

-Reduced risk of disease -Improved emotional and social wellness -Increased life expectancy

What types of activities can be done to prevent atrophy of skeletal muscles, and specifically, type II fibers?

-Running fast -Lifting relatively heavy weight -Jumping

Match the type of muscle with the corresponding tissues/structures. -Skeletal muscle tissue -Nerves -Blood vessels -Connective tissues -Caveolae -Nucleus

-Skeletal muscle -Skeletal muscle -Skeletal muscle -Skeletal muscle -Smooth muscle Smooth muscle

Which of the following are methods of improving flexibility of a muscle? Select all that apply.

-Static stretching -Jogging -Yoga

Which of the following fiber type transitions has research shown to occur with training? Select all that apply.

-Type IIb to Type IIa -Type IIa to Type IIb

What is the neuromuscular junction?

-Where the axons of motor nerves meet the muscle -A chemical synapse formed between a motor neuron and a muscle fiber

From a neurological perspective, in order to produce more force, which of the following must occur?

A greater number of motor units must be activated

Isometric

A muscle contraction wherein the muscle length does not change because the contractile force is equal to the resistive force

Eccentric

A muscle contraction wherein the muscle lengthens because the contractile force is less than the resistive force

Concentric

A muscle contraction wherein the muscle shortens because the contractile force is greater than the resistive force

Cross-bridge

A physical link between actin and myosin head

A lever is defined as which of the following?

A rigid structure that moves on a fixed point called the fulcrum

The time of a murder victim's death is commonly estimated by the flexibility of the body due to a lack of _______.

ATP

Power stroke

After myosin and actin form a cross-bridge¸Pi disassociates and the fiber shortens.

The muscles that are most directly involved in bringing about a movement are called which of the following?

Agonist

Disassociate

Another ATP attaches to myosin and the myosin and actin attachment weakens and detaches.

Skeletal muscle is made up of:

Both type I fibers (slow-twitch) and type II fibers (fast-twitch)

What molecule is responsible for the coupling of excitation of the fiber membrane to the muscle contraction?

Ca2+

When a person dies and rigor mortis occurs, which molecule causes the maintenance of a constant muscle contraction?

Ca2+

Which of the following is NOT a function of skeletal muscle?

Circulates blood through the body

An isometric muscle action is a muscle action in which the muscle:

Does not change length because the contractile force is equal to the resistive force

When a muscle lengthens as it contracts, this is known as a:

Eccentric contraction

What is the sequence of events that converts action potentials in a muscle fiber to a contraction?

Excitation contraction coupling

Muscle fibers in a skeletal muscle form bundles called ______________.

Fascicles

At what age does sarcopenia generally begin?

In one's 20s

Each of the following are examples of neural adaptations to anaerobic exercise EXCEPT:

Increase in muscle fiber number

Muscle hypertrophy is defined as which of the following?

Increase in the cross-sectional area of the existing fibers

Among people who do not exercise regularly, which of the following is a neurological training effect that will improve their fitness?

Increased ability to recruit Type II fibers

Examples of power movements include which of the following?

Jumping

Generally, muscle force is greater when which of the following occur?

More motor units are involved in a contraction.

Which of the following is not an effect of aging on the muscular system?

Muscle fibers become shorter

The contraction of a skeletal muscle exerts a pull on a bone because which of the following is true?

Muscles are attached to bones by tendons

If a motor neuron contained 1500 muscle fibers, what type of movements would this muscle likely be responsible for?

Powerful movements

Pennate fiber arrangements compared to nonpennate muscles, allow the muscle to do which of the following:

Produce more force

When an action potential moves down an excitable membrane, this process is called ______________.

Propagation

The replacement of type II fibers with fat is termed which of the following?

Sarcopenic obesity

In an apparently healthy person, which kinds of activities should be avoided to prevent a decline in muscular health?

Sitting too much because it causes atrophy of muscle fibers

When muscle contraction occurs, which of the following is true?

The Z-disks move closer together

Excitability

The ability of a muscle fiber to respond rapidly to a chemical or electrical signal

Contractility

The ability of the muscle to shorten and produce tension at its ends

Flexibility is defined as:

The ability to move a joint through a full range of motion

Elasticity

The ability to return to its original resting length after a stretch

What is the principle that describes how the strength by which a nerve or muscle fiber responds to a stimulus is independent of the strength of the stimulus?

The all-or-nothing principle

The disassociation of the myosin cross-bridge is directly activated by which of the following?

The attachment of ATP to myosin heads

Extensibility

The capacity of the muscle to stretch to the normal resting length after contracting

Reactivate

The myosin head is reactivated when ATP is hydrolyzed to ADP and inorganic phosphate.

Plasticity

The tendency to assume a new and greater length after a passive stretch

What happens to muscles that are not activated on a regular basis (months or years)?

They turn into fat and connective tissue

The purpose of reciprocal inhibition is which of the following?

To allow a coordinated, unresisted movement

Someone that is able to run a relatively fast marathon likely has a high percentage of which type of muscle fiber?

Type I

In what order are muscle fiber types recruited?

Type I, Type IIa, Type IIb

Which of the following defines muscle fiber recruitment?

Which and how many motor units are involved in a muscle contraction