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Which of the following is correctly paired?

Skeletal muscle: voluntary control

Muscle tissue does not

generate nerve impulses

Which type of muscle can contract without being stimulated by the nervous system?

cardiac

Which muscle characteristic describes the ability of muscle to respond to a stimulus

excitability

Which of the following surrounds the individual muscle cell?

endomysium

Muscle tissue has all of the following properties except ________.

secretion

Muscle contraction will always promote movement of body parts regardless of how they are attached.

false

One of the important functions of skeletal muscle contraction is production of heat.

true

The end of the muscle that typically moves when a muscle contracts is called the ________.

insertion

The connective tissue sheaths of skeletal muscle, in order from internal to external are the:

endomysium, perimysium, and epimysium

The smallest contractile unit of a muscle fiber is the

sarcomere.

Thick myofilaments are made of

myosin.

The major role of the sarcoplasmic reticulum is to regulate:

intracellular levels of Ca2

The distance between Z-discs ______ during muscle contraction

decreases

The sliding filament model of contraction states that:

during contraction, the thin filaments slide past the thick filaments so that actin and myosin filaments overlap

Which organelle contains the contractile elements found in skeletal muscle?

myofibril

Which protein inhibits skeletal muscle contraction, and what ion removes the inhibition?

Tropomyosin; calcium ions

What is the role of tropomyosin in skeletal muscles?

Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules

Myoglobin

stores oxygen in muscle cells

What structure in skeletal muscle cells functions in calcium storage

sarcoplasmic reticulum

What produces the striations of a skeletal muscle cell?

the arrangement of myofilaments

The contractile units of skeletal muscles are

myofibrils

What is the functional role of the T tubules

enhance cellular communication during muscle contraction

What is the role of calcium ions in muscle contraction?

bind to regulatory sites on troponin to remove contraction inhibition

The muscle cell membrane is called the

sarcolemma

The giant protein titin maintains the organization of the ________ assisting in muscle stretching

A band

What part of the sarcolemma contains acetylcholine receptors

motor end plate

The first step toward generating a skeletal muscle contraction is:

stimulation of the muscle by a nerve ending

The response of a motor unit to a single action potential of its motor neuron is called a:

muscle twitch

Slow oxidative muscle fibers are best suited for

endurance activities.

What is a cross bridge cycle?

thick filaments pulling thin filaments toward the center of the sarcomere

Which of the following factors influence the velocity and duration of muscle contraction

load placed on the muscle

What does oxygen deficit represent?

the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used

Creatine phosphate functions in the muscle cell by

storing energy that will be transferred to ADP to resynthesize ATP

What controls the force of muscle contraction?

multimotor unit summation

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

actin filaments

Rigor mortis occurs because

no ATP is available to release attached actin and myosin molecules

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to

lactic acid

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods

refractory period

In an isotonic contraction, the muscle

changes in length and moves the "load"

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is

glycolysis

Muscle tone is

a state of sustained partial contraction

The sliding filament model of contraction involves

actin and myosin sliding past each other and partially overlapping

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction

acetylcholinesterase destroying the ACh

Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped

no muscle tension could be generated

The calcium calmodulin system of contraction regulation is found in

smooth muscle only.

Which of the following is true

Skeletal muscle fibers contain sarcomeres; smooth muscle fibers do not

The type of muscle found in the walls of most hollow organs is

single-unit smooth muscle

Smooth muscles that act like skeletal muscles but are controlled by autonomic nerves and hormones are

multiunit muscles

Peristalsis is characteristic of smooth muscle

true

are muscles that serve as the primary promoters of a movement.

Agonists

When the term biceps, triceps, or quadriceps forms part of a muscle's name, what does it tell you about the muscle

The muscle has two, three, or four origins, respectively

A muscle group that works with and assists the action of a prime mover is a

synergist

Which generalization concerning movement by skeletal muscles is not true

During contraction the two articulating bones move equally

Which of the following is not used as a criterion for naming muscles

Whether the muscle is controlled by the involuntary or voluntary nervous system

Which of the following muscles is named for its origin and insertion?

sternocleidomastoid

Which of the following muscles is named for its action?

levator labii superioris

What is a muscle that provides the major force for producing a specific movement called?

an agonist

What are the muscles that are found at openings of the body collectively called?

circular muscles

Muscles are only able to pull, they never push.

true

Which of the following is correctly matched?

Convergent arrangement of fascicles: fan shaped muscle

Most skeletal muscles of the body act as:

third-class levers.

Which of the following movements demonstrates a first-class lever?

raising your head up off your chest

Which type of lever is demonstrated by using scissors?

a first-class lever

What is the major factor controlling how levers work?

the difference in the positioning of the effort, load, and fulcrum

If a lever operates at a mechanical disadvantage, it means that the ________.

load is far from the fulcrum and the effort is applied near the fulcrum

What type of muscle assists an agonist by causing a like movement or by stabilizing a joint over which an agonist acts?

a synergist

If L = load, F = fulcrum, and E = effort, what type of lever system is described as LEF?

third-class lever

Both first- and second-class levers operate at a mechanical disadvantage.

False

The main forearm extensor is the:

triceps brachii.

Which of the following is NOT a rotator cuff muscle?

teres major

The supraspinatus is named for its location on the posterior aspect of the scapula above the spine. What is its action?

to stabilize the shoulder joint and help prevent downward location of the humerus and to assist in abduction

The extensor carpi radialis brevis ________.

extends and abducts the wrist and is short

Which of the following types of glial cells monitor the health of neurons, and can transform into a special type of macrophage to protect endangered neurons?

Microglia

Which of the following types of glial cells produce the myelin sheaths that insulate the neural fibers in the CNS?

Oligodendrocytes

Which of the following PNS neuroglia help to form myelin sheaths around larger nerve fibers in the PNS?

Schwann cells

Which of the following is true of axons?

Each neuron has a single axon.

Ependymal cells ________.

help to circulate the cerebrospinal fluid

Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________.

astrocytes

Schwann cells are functionally similar to ________.

oligodendrocytes

Neurons and nerve cells are different names for the same thing.

true

Which neuron circuit pattern is involved in the control of rhythmic activities such as breathing?

reverberating circuit

Select the correct statement about serial processing.

Spinal reflexes are an example of serial processing.

Which neurotransmitter(s) is/are the body's natural pain killer?

endorphins

Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?

acetylcholine

What is the role of acetylcholinesterase?

destroy ACh a brief period after its release by the axon endings

The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.

neurotransmitter

Which of the following is not a chemical class of neurotransmitters?

nucleic acid

Enkephalins and endorphins are peptides that act like morphine.

true

Which of the following circuit types is involved in the control of rhythmic activities such as the sleep-wake cycle, breathing, and certain motor activities (such as arm swinging when walking)?

Reverberating circuits

An impulse from one nerve cell is communicated to another nerve cell via the ________.

synapse

An inhibitory postsynaptic potential (IPSP) is associated with ________.

hyperpolarization

Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?

A single type of channel will open, permitting simultaneous flow of sodium and potassium.

In a synapse, neurotransmitters are stored in vesicles located in the

presynaptic neuron

An action potential releases neurotransmitter from a neuron by opening which of the following channels

voltage-gated Ca2+ channels

Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane.

chemically gated; postsynaptic

Binding of the neurotransmitter to its receptor causes the membrane to __________.

either depolarize or hyperpolarize

The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned?

acetylcholine

What type of conduction takes place in unmyelinated axons?

Continuous conduction

An action potential is self-regenerating because __________.

depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment

Why does regeneration of the action potential occur in one direction, rather than in two directions?

The inactivation gates of voltage-gated Na+ channels close in the node, or segment, that has just fired an action potential.

What is the function of the myelin sheath?

The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals.

What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization?

Inactivation gates of voltage-gated Na+ channels close, while activation gates of voltage-gated K+ channels open.

In which type of axon will velocity of action potential conduction be the fastest?

Myelinated axons with the largest diameter

How is an action potential propagated along an axon?

An influx of sodium ions from the current action potential depolarizes the adjacent area.

Why does the action potential only move away from the cell body?

The areas that have had the action potential are refractory to a new action potential.

The velocity of the action potential is fastest in which of the following axons?

a small myelinated axon

Where do most action potentials originate?

Initial segment

What opens first in response to a threshold stimulus?

Voltage-gated Na+ channels

What characterizes depolarization, the first phase of the action potential?

The membrane potential changes from a negative value to a positive value.

What characterizes repolarization, the second phase of the action potential?

Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.

What event triggers the generation of an action potential?

The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.

What is the first change to occur in response to a threshold stimulus?

Voltage-gated Na+ channels change shape, and their activation gates open.

Where in the neuron is an action potential initially generated?

axon hillock

The depolarization phase of an action potential results from the opening of which channels?

voltage-gated Na+ channels

The repolarization phase of an action potential results from __________.

the opening of voltage-gated K+ channels

Hyperpolarization results from __________.

slow closing of voltage-gated K+ channels

What is the magnitude (amplitude) of an action potential?

100 mV

Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?

Resting membrane potential (RMP)

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?

Leak channels

On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?

The inside surface of the plasma is much more negatively charged than the outside surface.

The plasma membrane is much more permeable to K+ than to Na+. Why?

There are many more K+ leak channels than Na+ leak channels in the plasma membrane.

The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors.

The presence of concentration gradients and leak channels

What prevents the Na+ and K+ gradients from dissipating?

Na+-K+ ATPase

The membranes of neurons at rest are very permeable to _____ but only slightly permeable to _____.

K+; Na+

During depolarization, which gradient(s) move(s) Na+ into the cell?

both the electrical and chemical gradients

What is the value for the resting membrane potential for most neurons?

-70 mV

The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped?

Na+ is pumped out of the cell and K+ is pumped into the cell.

The concentrations of which two ions are highest outside the cell.

Na+ and Cl-

Which of the following are bundles of neurofilaments important in maintaining the shape and integrity of neurons?

Neurofibrils

Which of the following is the conducting region of the neuron?

Axon

Which of the following are gaps found along a myelin sheath?

Nodes of Ranvier

Which criteria is used to functionally classify neurons?

The direction in which the nerve impulse travels relative to the central nervous system.

Which of the following is not a functional classification of neurons?

Extraneurons

Which of the following does not factor into the rate of impulse propagation?

The number of axon collaterals extending from a truncated axon.

Which of the following is not true of an electrical synapse?

They are specialized for release and reception of chemical neurotransmitters.

Which part of the neuron is responsible for generating a nerve impulse?

axon

Bipolar neurons are commonly ________.

found in the retina of the eye

The part of a neuron that conducts impulses away from its cell body is called a(n) ________.

axon

Collections of nerve cell bodies outside the central nervous system are called ________.

ganglia

A neuron that has as its primary function the job of connecting other neurons is called a(n) ________.

association neuron

Which of the following is not one of the basic functions of the nervous system?

Neural genesis

Which of the following allows us to consciously control our skeletal muscles?

The somatic nervous system

What part of the nervous system performs information processing and integration?

central nervous system

Which of the following types of neurons carries impulses away from the CNS?

motor

Which of the choices below describes the ANS?

motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands

Which of the following describes the nervous system integrative function

analyzes sensory information, stores information, makes decisions

The term central nervous system refers to the ________.

brain and spinal cord

Efferent nerve fibers may be described as motor nerve fibers.

True

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