BSC 215 Exam 3

Actin and myosin are both found in the:

A-band

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

A-bands get smaller

The first step of the crossbridge cycle begins when:

ATP hydrolysis "cocks" the myosin head

Muscles remain in a contracted state during rigor mortis because:

ATP is required to release the attached actin and myosin molecules

Which of the following neurotransmitter is not a type of catecholamine?

Acetylcholine

Which of the following substances is released from synaptic knobs in order to initiate a skeletal muscle contraction?

Acetylcholine

In skeletal muscle, contraction is voluntarily controlled, but the process is stimulated through a neuromuscular junction (NMJ). When the NMJ releases the necessary neurotransmitter ACH to start the cascade, which ion is ultimately responsible for allowing the sliding filament theory?

Ca2+

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

Defensive

which sequence of structures correctly indicates the direction in which an electrical signal is carried in a typical multipolar neuron

Dendrites, cell body, and axon

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

Endomysium

which of the following pairs of neurotransmitters are strictly inhibitory?

Glycine and GABA

Which neurotransmitter is widely used by the autonomic nervous system (ANS), where it influences functions such as heart rate, blood pressure, and digestion?

Norepinephrine

Which of the following neuroglial cells make myelin sheaths for neurons in the Central Nervous System?

Ogliodendrocytes

What is thought to be one of the major neurotransmitters involved in mood regulation, motor behaviors, feeding behaviors, and daily rhythms and is a common target in the treatment of depression?

Serotonin

Which neuropeptide neurotransmitter is released from fibers transmitting sensory information about pain and temperature?

Substance P

What causes the release of myosin heads from actin filaments after the power stroke?

The binding of ATP molecules to the myosin heads

The fastest muscle contraction would be produced by a __________.

Type IIx fibers

Which of the following correctly represents Ohm's Law?

Voltage/Resistance

what anchors thin and elastic filaments in place with the myofibril?

Z disc

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

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

cholinergic synapses use the neurotransmitter ___________

acetylcholine

The neurotransmitter used in a neuromuscular junction is

acetylcholine (ACh)

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

actin filaments

Local depolarization of the motor end plate is called:

an end plate potential

Thick filaments:

are composed primarily of the protein myosin.

In response to physical inactivity, we expect to see muscle _______

atrophy

What neuron structure does not contain protein-making organelles?

axon

which of the following descriptions best characterizes a converging circuit

axon terminals from multiple input neurons join onto a single postsynaptic neuron

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

calcium ions

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

contraction

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

creatine phosphate

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

crossbridge

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

crossbridge

Which of the following effects does not occur when neuromodulators bind

degenerate synaptic vesicles

which of the following electrical terms used in electrophysiology is synonymous with the mechanical event of a muscle contraction?

depolarization

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

endurance training

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

excitation phase

The order in which the three phases of muscle contraction occur is:

excitation phase, excitation-contraction coupling, contraction phase

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

extensibility

When a muscle contracts, the functional units of muscles will lengthen to show they are actively contracting

false

When muscle fibers are stimulated at a high frequency and the tension remains constant at a maximal level the muscle fiber has transitioned into ______.

fused or complete tetanus

when muscle fibers are stimulated so frequently they do not have an opportunity to relax, they are experiencing

fused or complete tetanus

What is the basic function of all muscle tissue?

generate muscle tension

What is considered to be the most important excitatory neurotransmitter in the brain?

glutamate

a pathway of ATP production that results in the formation of lactic acid is

glycolytic catabolism

what change in membrane potential is caused when glycine and GABA stimulate the opening of chloride ion channels?

hyperpolarization

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

increased availability of oxygen to muscle fibers

The majority of neurons are functionally classified as _________ neurons

interneurons

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

isometric

A muscle contraction in which a muscle develops tension and the muscle shortens (As in lifting an object) is termed a _____ contraction

isotonic concentric

What type of contraction requires the greatest amount of tension?

isotonic eccentric contraction

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

it has many peripheral nuclei

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

latent period

What type of neurotransmitter receptors elicit much slower changes in the membrane potential of the postsynaptic neuron, but the effects are typically longer lasting and more varied?

metabotropic receptors

how many neurotransmitters operating in the human nervous system have been identified?

more than 100

where are the receptors for acetylcholine located?

motor end plate

A single motor neuron together with all the muscle fibers it innervates is called

motor unit

A fascicle (or fasciculus) is a bundle of:

muscle fibers

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

muscle tone

Another name for a muscle cell is a _______

myocyte

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

myofibrils

which statement best describes the function of myoglobin?

myoglobin stores oxygen in muscle cells

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

neuromuscular junction

The same ________ can have different effects depending on the properties of the ________.

neurotransmitter; receptor

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

oxidative catabolism

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

peristalsis

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

propagated

what is the response of the presynaptic neuron after acetylcholinesterase (AChE) acts?

reabsorbs choline

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

recovery period

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

recruitment

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

recruitment

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 __________.

refractory period

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.

relaxation

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

repolarization

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

resistance training

the Na+/K+ pump helps a muscle cell maintain a state of

resting membrane potential

The plasma membrane of a muscle cell is known as the _____

sarcolemma

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

sarcomere

What is the functional unit of the myofibril?

sarcomere

THe _______ contains cytosol and all of the organelles in the muscle cell

sarcoplasm

The storage and release of calcium ions is the key function of the ______

sarcoplasmic reticulum

What structure found in the peripheral nervous system (PNS) promotes regeneration of a damaged axon?

schwann cell

The predominant type of smooth muscle in the body found in nearly all hollow organs is the ______.

single unit smooth muscle

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

slow twitch fibers

Type 1 fibers lack

speed

Smooth muscle forms rings called ________ that are usually contracted but relaxed periodically to allow substances to pass through them

sphincters

smooth muscles lack

striations

what characteristic is not descriptive of skeletal muscle tissue?

surround hollow organs

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

synapse

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

synaptic cleft

neuronal pools are located within

the CNS

The separation of charges across the plasma membrane is called:

the electrical gradient

What do neurotransmitters that bind ionotropic receptors directly control?

the movement of ions into or out of the postsynaptic neuron

Myofilaments are bundles of hundreds to thousands of the following types of proteins except:

transport proteins

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

transverse T tubules

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

transverse tubules (T-Tubules)

Calcium ions bind to which regulatory protein?

troponin

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

voltage gated channels

what characteristic is not descriptive of cardiac muscle tissue?

voluntary muscle contractions

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

within lateral sacs of the sarcoplasmic reticulum