Chap 10 Muscle Tissue Flashcards
The tissue surrounding an entire muscle is known as
epimysium
the tissue that surrounds a muscle cell (myofiber) is known as
endomysium
Muscle fibers re bundled into groups known as
fascicles
Bundles of muscle fibers (fascicles) are wrapped by a tissue known as
perimysium
A connective tissue on the surface of muscles (that extends onto the tendon and bone) is known as
fascia
One of the characteristics of muscle tissue is that is has conductivity. Which of the following best describes this characteristic?
Muscles have local electrical charges that are capable of moving along the muscle fiber.
One of the characteristics of muscle tissue is that is has extensibility. Which of the following best describes this characteristic?
Muscles can stretch when needed.
One of the characteristics of muscle tissue is that is has excitability. Which of the following best describes this characteristic?
Muscles contract when stimulated.
Which of the following groups are considered to be parts of the series-elastic components of muscle?
endomysium, perimysium, epimysium, fascia, and tendons
Which of the following best describes the function of the series-elastic component of muscle?
These are not excitable or contractile, but are extensible and elastic.
What part of a muscle is the muscle fiber?
muscle cell itself
The outer membrane of the muscle fiber is known as the
sarcolemma
The cytoplasm within the muscle fiber is known as the
sarcoplasm
The cytoplasm within the muscle fiber contains a molecule to distribute oxygen within the cell. This molecule is known as
myoglobin
The molecule within the cytoplasm of a muscle fiber that supplies quick energy for contraction is
glycogen
The myofilaments within the muscle fiber are composed of three integral items. Which of the following lists the components correctly?
myosin, actin, and elastic (titin) filament.
Thick filaments within the myofibril are composed of
myosin
Thin filaments within the myofibril are composed primarily of
actin
The elastic filaments within a myofibril are composed of molecules known as
titin
The elastic filaments within a myofibril are attached to and wound around, which of the following?
myosin
In the myofibril, ATP is used for which of the following?
muscle tone
muscle contraction
muscle relaxation
Which of the following tissues has the greatest ability to repair itself?
smooth muscle
Of the following muscles types, which one has long, cylindrical-shaped cells?
skeletal muscle
Of the following muscle types, which one has only one nucleus?
smooth muscle
Of the following muscle types, which one does NOT have striations?
smooth muscle
Of the following muscle types, which one is usually voluntary?
skeletal muscle
Objects that move through organs that are surrounded by smooth muscle are often moved by means of
peristalsis.
Of the following muscle types, which one is found in the middle layer of the aorta?
smooth muscle
The “all-or-none” concept of skeletal muscle contraction means that
muscle fibers contract completely.
Which of the following best describes the use of muscle tone in the body?
It keeps our backs straight and our heads up.
Action potential frequency is best described as:
The number of action potentials produced per unit of time.
Triads in skeletal muscle consist of which of the following?
two terminal cisternae and a T-tubule.
When acetylcholine is broken down by acetylcholinesterase in the synaptic cleft, what happens to the choline?
It is reabsorbed at the presynaptic terminal and combined with more acetic acid to make acetylcholine.
The recovery stroke in muscle contraction involves which of the following?
return of the myosin head to its original position after the cross bridge releases
Which of the following is one of the primary functions of muscle tissue?
heat production
The ability of a muscle to be stimulated is called
excitability
Which of the following muscles is involuntary and is the most widely found throughout the body?
smooth
Which of the following types of muscles contain intercalated discs and branching fibers?
cardiac
Which of the following muscle types contains peripherally located, multiple nuclei in its cells?
skeletal
The striations in striated muscle correspond with actual molecular structures. Which of the following is the Z line?
an attachment point for actin molecules
The striations in striated muscle correspond with actual molecular structures. Which of the following is the I band?
a band where only actin molecules are found
The striations in striated muscle correspond with actual molecular structures. Which of the following is the H band?
a band where only myosin molecules are found
Which of the following is the A band within a myofibril?
myosin myofilaments in profile
Which of the following is the unit in a myofibril from Z line to Z line?
sarcomere
Which of the following best describes a muscle motor unit?
one nerve fiber and all the muscle fibers innervated by that nerve
On the surface of the sarcolemma, the voltage may shift up and down rapidly. This change in electrical potential caused by shifts in ions across the membrane is known as a(n)
action potential
During an action potential, calcium is released into the sarcoplasm, near the actin and myosin molecules. Which of the following is the best explanation of what the calcium does?
The calcium removes the tropomyosin block.
When the myosin head (of the thick filament) flexes into a bend, while releasing ADP and inorganic phosphate, pulling the thin filament along with it, this is called the
power stroke
When the thick and the thin filaments pull together, which of the following is TRUE?
The sarcomere gets shorter.
The tissues of cardiac muscle have unique structures known as
intercalated discs
Intercalated discs are capable of doing which of the following?
pass electrical stimulation to other cardiac cells
Which of the following is unique about cardiac muscle tissue?
The cells have large mitochondria.
Which of the following is TRUE of cardiac tissue?
It contains only small amounts of myoglobin and glycogen.
Which of the following proteins attaches Z discs to myosin myofilaments?
titin
The functional connection between a nerve fiber and a muscle fiber is called a(an)
synapse
When the neuron stimulates a muscle fiber, what molecule diffuses across the gap between them?
acetylcholine
Once a signal molecule has left the neuron and binds to a receptor molecule on the surface of the muscle fiber, a sodium channel opens, allowing entry of sodium into the muscle fiber. Which substance is then released from the sarcoplasmic reticulum?
calcium
Muscle fibers and neurons are called electrically excitable cells because
their plasma membranes exhibit voltage changes in response to stimulation
Movement of which of the following proteins causes exposure of the active sites on the actin molecule?
tropomyosin
What type of molecule is acetylcholine?
It is a neurotransmitter.
Binding of acetylcholine with its receptor on muscle cells causes
opening of a ligand-gated sodium channel
What kind of molecule is ACh?
protein
In the muscle fiber, what is the function of acetylcholinesterase?
It deactivates acetylcholine.
What is the voltage of the resting potential of the sarcolemma?
-70 mv
Which of the following is a molecule that binds to a receptor?
acetylcholine
Which of the following assures quick removal of neurotransmitter at the junction between a nerve and a muscle?
acetylcholinesterase
A buildup of acetylcholine in the synaptic cleft without breakdown may cause which of the following?
spastic paralysis
In a muscle twitch, which of the following represents the time between application of a stimulus and the beginning of contraction?
lag
Which of the following determines the height of the peaks in multiple motor unit summation?
the amount of tension produced by the number of motor units responding
Which of the following is true of an isometric muscle contraction?
Not enough tension is generated so the muscle does not change in length
Eccentric muscle contractions occur when
a person slowly lowers a heavy weight
All of the following are true of muscle tone
exists for long periods of time
helps maintain the head upright
Tension in the whole muscle remains constant.
Smooth body movements result from
both incomplete and complete titanic contractions of motor units contracting out of phase with each other.
Active tension in a muscle is defined as
the tension applied to a load when the muscle contracts.
The sum of active and passive tension is called
total tension.
Which of the following types of muscle fatigue represents depletion of ATP?
muscular
Which of the following types of fatigue is caused by the release of more acetylcholine than can be produced to replace it?
synaptic
Muscle soreness can be produced by which of the following?
muscular fatigue
enzymes in the extracellular fluid commonly found within muscle
collagen in the extracellular fluid
Which of the following represents extreme muscular fatigue when the muscle is incapable of either contracting or relaxing?
physiological contracture
Which of the following energy storages source is most commonly used during the first 10 seconds of exercise?
creatine phosphate
During anaerobic respiration, what is the net amount of ATP produced?
2 ATP
Which of the following represents the amount of oxygen that is necessary for the body to recover from anaerobic respiration?
oxygen debt
All of the following are characteristics of slow-twitch fibers except
large diameter.
All of the following are true about fast-twitch fibers except
high amount of myoglobin
Which of the following is true about distribution of fast and slow-twitch fibers in the body?
Slow-twitch fibers are usually more resistant to fatigue.
A person with an arm immobilized in a cast for 6 weeks will
develop muscular atrophy.
Which of the following effects of exercise elevate the body temperature?
elevated metabolism from the oxygen debt
vasodilation of blood vessels in the skin
skeletal muscle contractions
Unitary smooth muscle is found in which of the following locations in the body?
digestive tract
reproductive tract
urinary tract
Which of the following is true about smooth muscle?
The resting membrane potential is less negative than in skeletal muscle.
Which of the following are the most common neurotransmitters in smooth muscle?
acetylcholine and norepinephrine
All of the following are properties of cardiac muscle cells except
shorter in duration of contraction than skeletal muscles.
Which of the following is not an effect of aging on skeletal muscle?
increased myoglobin
Which of the following exercises slows the loss of muscle fibers in older people?
swimming
Which of the following is true about skeletal muscle fibers in aging people?
The number of fibers decreases.
There is a decreased density of capillaries that supply muscle cells.
The number of motor neurons that innervate skeletal muscle decreases.
