Chapter 10 DSM

an electrical gradient

The separation of charges across the plasma membrane is called:

are composed primarily of the protein myosin.

Thick filaments:

Endomysium

Which of the following wraps and surrounds an individual skeletal muscle fiber?

sarcomere

The basic contractile unit of muscle fiber that extends from one Z-disc to the next

actin

Thin filaments primarily made of a protein, playing a crucial role in muscle contraction

myosin

Thick filaments, central to muscle contraction, interacting with thin filaments

A band

The dark region of a sarcomere, containing the entire length of the myosin filaments

I band

The light region of the sarcomere, containing only actin filaments

sarcoplasm

The _____ contains cytosol and all of the organelles in the muscle cell.

sarcoplasmic reticulum

The storage and release of calcium ions is the key function of the __________.

myofibrils

The sarcoplasm of muscle cells contain cylindrical organelles called _____, which make up 50-80% of its volume.

actin, tropomyosin, troponin

Which proteins are primarily involved in forming the thin filaments of a sarcomere?

Z-disc

What anchors thin and elastic filaments in place within the myofibril?

transverse tubules

Deep inward extensions of the sarcolemma form a tunnel-like network inside the muscle cell known as __________.

A band

Actin and myosin are both found in the:

Surround hollow organs

What characteristic is not descriptive of skeletal muscle tissue?

muscle fibers

Long, cylindrical cells that make up skeletal muscles

myofibrils

Threadlike structures containing a series of sarcomeres

endomysium

connective tissue surrounding each individual muscle fiber

fascicles

Bundles of muscle fibers within a muscle

perimysium

Connective tissue surrounding each fascicle

epimysium

Connective tissue that surrounds the entire muscle

sarcomere

Basic contracting unit of a muscle fiber

sarcomere

The functional unit of contraction, where muscle tension is produced, is the ____.

voluntary muscle contractions

What characteristic is not descriptive of cardiac muscle tissue?

sarcolemma

The plasma membrane of a muscle cell is known as the __________.

defensive

Which of the following properties is not common to all muscle cells?

voltage-gated channels

Ion channels that open and close in response to a change in membrane potential are called _____.

transverse tubules (T-tubules)

Inward extensions of the sarcolemma that dive deeply into the muscle fiber and surround each myofibril are known as _____.

extensibility

The degree to which a muscle cell can stretch depends on its __________.

a high concentration of sodium outside the cell and a high concentration of potassium inside the cytosol.

In order to keep a resting membrane potential, the active transport of the sodium and potassium pump must function to keep:

resting membrane potential

The Na⁺/K⁺ pump helps a muscle cell maintain a state of __________.

propagated

Action potentials do not stay in one place, they are _____ throughout the entire sarcolemma like ripples in a pond.

repolarization

During an action potential, the loss of potassium ions from the cell results in:

myocyte

Another name for a muscle cell is a ______.

generate muscle tension

What is the basic function of all muscle tissue?

A bands get smaller

Which of the following events will not occur within the sarcomeres of a contracting muscle fiber?

neuromuscular junction

The synapse of a motor neuron with a muscle fiber is known as the __________.

Type IIx fibers

The fastest muscle contraction would be produced by which of the following fiber types?

relaxation

Muscle ______ occurs when ACh release is stopped, the remaining ACh in the synaptic cleft is broken down, and the calcium ion concentration in the cytosol returns to its resting levels.

creatine phosphate

ATP is rapidly consumed when muscle contraction begins but is regenerated almost immediately by ______________.

troponin

Calcium ions bind to which regulatory protein?

glycolytic catabolism

A pathway of ATP production that results in the formation of lactic acid is __________.

action potential travels along the sarcolemma, release of calcium ions from the sarcoplasmic reticulum, binding of calcium ions to troponin

What events happen during the excitation-contraction coupling in muscle fibers?

contraction

Muscle ______ is simply a succession of crossbridge cycles and the resulting production of force.

refractory period

Between the start of the latent period and the start of the contraction period, there is a time interval during which the muscle cannot respond to another stimulus. This brief period is known as the __________.

crossbridgepowe

The binding of a myosin head to an actin molecule is termed a __________.

excitation phase

The transmission of a signal from the motor neuron to the sarcolemma of a muscle fiber occurs during the:

slow-twitch fibers

Fibers with low myosin ATPase activity found in muscles that require slow sustained contractions, are known as _____.

crossbridge

When a myosin head binds to an actin molecule, a(n) ______ is formed.

ATP is required to release the attached actin and myosin molecules.

Muscles remain in a contracted state during rigor mortis because:

within lateral sacs of the sarcoplasmic reticulum.

When a muscle fiber is relaxed, calcium ions would be:

motor end plate

Where are receptors for acetylcholine located?

latent period

The amount of time it takes for an action potential to spread through the sarcolemma is known as the:

oxidative catabolism

Through which ATP-generating mechanism can long-lasting muscle contractions be sustained?

myoglobin stores oxygen in muscle cells

Which statement best describes the function of myoglobin?

synapse

Each connection where a single motor neuron communicates with many muscle fibers is known as a _________.   

an end-plate potential

Local depolarization of the motor end plate is called:

acetylcholine (ACh)

The neurotransmitter used in a neuromuscular junction is:

actin filaments

During muscle contraction, myosin crossbridges bind to active sites on __________.

synaptic cleft

The narrow space between the axon terminal and the muscle fiber is known as the:

excitation phase, excitation-contraction coupling, contraction phase

Which of the following correctly represents the three phases of muscle contraction?

high aerobic capacity, high fatigue resistance, high myoglobin content

Which of the following are characteristics of type I muscle fibers?

speed

Type I fibers lack __________.

atrophy

In response to physical inactivity, we expect to see muscles __________.

endurance training

A type of physical training primarily aimed at improving the ability to resist or withstand fatigue, often focusing on cardiovascular health and muscle stamina

resistance training

Training that involves lifting weights to improve muscle strength, power, and mass

muscle fatigue

A state where the muscle loses its ability to contract after prolonged activity or stress, often accompanied by a feeling of tiredness and weakness

recovery period

The phase following physical exertion during which muscles repair, adapt, and restore energy stores

muscle hypertrophy

The increase in the size of muscle fibers, typically achieved through strength training and exercise

recovery period

The persistent increased rate of breathing following exercise and the time needed to return to the pre-exercise state is known as (the) _____.

Release of calcium ions and interaction with calmodulin

What mechanism primarily triggers contraction in smooth muscle cells?

calcium ions

Calmodulin binds ______ in smooth muscle cells, resulting in contraction of the tissue.  

isometric

The type of contraction in which length of the muscle fibers does not change is called __________.

recruitment

The increase in muscle tension that is produced by increasing the number of active motor units is called __________.

striations

Smooth muscles lack _____.

motor unit

A single motor neuron together with all the skeletal muscle fibers it innervates is called a _____.

peristalsis

Smooth muscle propels materials through the hollow organs of the digestive, urinary and reproductive systems by a process known as ______.

resistance training.

Activities that involve the use of free weights is a type of:

endurance training

Activities such as cycling, jogging, cross-country skiing and distance swimming are all types of _____.

all muscle fibers in a motor unit are of the same type, smaller motor units are typically recruited first

What are true about motor units in skeletal muscles?

It has many peripheral nuclei.

Which of the following characteristics is not associated with cardiac muscle?

Autorhythmicity, presence of intercalated discs

Identify the features that are exclusive to cardiac muscle tissue.

muscle tone

Even when a muscle is at rest, it still has some degree of tension. This small amount of tension produces what is known as ______.

increased availability of oxygen to muscle fibers.

Muscle fatigue, the inability to maintain a given level of intensity of a particular exercise, can result from all of the following except:

sphincters

Smooth muscle forms rings called ___________ that are usually contracted but relax periodically to allow substances to pass through them.

recruitment

The activation of additional motor units in order to produce a contraction with greater tension is known as ______.