Chapter 9
Which of the following is NOT true of the latch state of smooth muscle contraction
It occurs when the phosphate is removed while the cross- bridges are not attached to actin
which of the following connective tissue layers is outside all the others
epimysium
The elevated oxygen consumption relative to activity level after exercise has ended is called
excess post- exercise oxygen consumption
acetylcholine is realized from the presynaptic terminal by the process of
exocytosis
Consider the following four phases and select the one that does not belong with the others
feels runners in marathon
Which of the following events occurs during the lag phase of a muscle twitch
The action potential is propagated fringe presynaptic to postsynaptic membrane
in order for muscle relaxation to occur
The active sites on actin must be blocked
Which of the following would occur as a result of a single muscle contraction
Twitch
The active sites to which cross- bridges attach are found on the actin myofilaments
actin myofilaments
During the contraction phase a muscle twitch
actin-myosin cross-bridges form.
Tetanus of muscles is described as
action potential frequency is high enough that no relaxation of muscle fibers occurs.
Which of the following correctly describes myoglobin special function in muscle tissue
acts as a reservoir for 02
A lack of mitochondria within skeletal muscle fibers would impair which ATP- yeilding
aerobic respiration
A stimulus either causes an action potential or it doesn't. this is called
an all- or- none response
Which type of respiration rapidly produces ATP for short period of time
anaerobic
smooth muscle and cardiac muscle are similar in that they both
are under involuntary control
in smooth muscle cross- biding occurs due to
both CA2+ binding to calmodulin and myosin kinase adding a phosphate t0 myosin heads
which type of muscle tissue is autorhythmic
both cardiac and and smooth muscle are correct
which type of muscle tissue posses striations
both skeletal and cardiac muscle are correct
when an action potential reaches the presynaptic terminal
calcium ions diffuse into the presynaptic terminal through voltage-gated ions
which type of muscle tissue causes contraction of the heart
cardiac muscle
which type of muscle tissue has cells that branch
cardiac muscle
If Na+ cannot enter a muscle fiber in response to a stimulus,
contraction cannot occur
A drug that interfere with the active transport of Ca2+ from the sarcoplasm back into the sarcoplasmic reticulum would result in
contraction with no relaxation
During resting conditions ________ is synthesized to store energy
creatine phosphate
rigor mortis occurs after death because
cross-bridges form but can't release.
sarcoplasm is the
cytoplasm of a muscle fiber
one ATP molecule is required for
formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge.
which of the following is part of a thin my-filament
globular (G) actin
Troponin
has a calcium-binding site.
Intense exercise that results in a great deal of anaerobic activity
increases muscular strength and mass
the electrical properties of cells are the result of
ion concentration differences across the plasma membrane
physiological contracture
is a condition in which cross-bridges cannot release.
Muscle tone
is a constant tension produced by muscles for long periods of time.
a facile
is surround by perimysium
complete tenus
is the condition in which stimuli occur so rapidly that there are no intervening relaxations
which of the following actions is caused by contraction of skeletal muscle
moving your feet walking
The stretch of elastic components of a muscle adds to the increased tension during
multiple wave summation
Identify the statement concerning general functional characteristics of muscle that is true.
muscle tissue shortens forcefully but lengthens passively
skeletal muscle develops from cells called
myoblasts
muscle hypertrophy results from increased numbers of
myofibrils and sarcomeres
ATPhase is found in
myosin heads
excitation-contraction coupling
myosin heads bind to exposed active sites on actin.
Which of the following is mismatched
myosin myofilaments - thin myofilaments
which of the following events occurs on the postsynaptic membrane
neurotransmitter combines with a receptor molecule
which of the following structures contain the other four items listed
nueromuscular junction
The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called
nueromuscular junctions
visceral smooth muscle
occurs in sheets and exhibits numerous gap junctions.
An action potential
occurs when the local potential reaches threshold level
A sarcomere extends from
one Z disk to an adjacent Z disk
When repolarization of the cell membrane is complete, the
orignal polarity if the cell is restored
the sarcolemma is the
plasma membrane of a muscle fiber
skeletal muscle fibers
possess striations
Which of the following is true during the resting membrane potential
potassium is concentrated primarily inside the cell
A myofilament is the
protein strand composed of actin or myosin
Too much acetyllcholinesterase causes
rapid degradation of acetylcholine
After contraction has occurred, the Ca2+
released from troponin
myosin phosphates
removes phosphate from myosin
Muscles exhibit the property of excitability. This means that the muscle
responds to stimulation by the nervous system
Multiple wave summation
results in complete and incomplete tetanus.
T tables are invaginations of the
sarcolemma
Maureen is hiking in the cold, and to maintain homeostasis her body begins to
shiver
Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the
size of muscle fibers
which type of muscle tissue has neuromuscular junctions
skeletal muscle
which type of muscle tissue is multinucleated
skeletal muscle
which type of muscle tissue would cause flexion and extension of the arm
skeletal muscle
The model that describes the contraction of the muscle is called the
sliding filament model
which type of muscle tissue causes vasoconstriction
smooth muscle
which type of muscle tissue has spindle- shaped cells
smooth muscle
which type of muscle tissues causes peristalsis
smooth muscle
which of the following statements about muscle tissue is true
smooth muscle is found in the walls of hollow organs
the sarcoplasmic reticulum
stores Ca2+
A sarcomere is the
structural and functional unit of the skeletal muscle fiber
Endomysium is a delicate network of loose connective tissue that
surrounds each muscle fibers
epimysium
surrounds individuals muscles
Susan slipped on the ice and was unable to be fully mobile for several days. What disruption to homeostasis would you predict she experienced during her immobile period in terms of her muscular system?
susan was more cold than usual because her inactivity prevented her muscles from helping to regulate her body temperature
channels that open or close in response to changes in the electrical charge of voltage across the plasma membrane are called
voltage gated ion channels
multiunit smooth muscle is located in the
wall of blood vessels
The region of the sacromere that contains both actin and myosin myofilaments is called the
A band
Which of the following statements concerning smooth muscle is true
A calcium- calmodulin complex initiates cross- bridges formation
An isometric contraction is described as
A muscle produces an increasing tension as the length remains constant
synaptic vesicles in the nueromuscular junction contain
Acetylcholine
Heather is watching a movie. Which type of chemical pathway does her muscles depend on at this time?
Aerboic respiration
When skeletal muscle is producing CO2 and water while making ATP, which chemical processes could be active at this time?
Aerobic respirations
What is an oxygen deficit
After exercise, the O2 taken in that exceeds the O2 required for resting metabolism
aerboic exercise
All of these choices are correct
Treppe
All of these choices are correct.
Arrange the following list of biochemical events in the correct sequence
1,3,4,2,5
list the structures in order from smallest to largest
2,3,1,4
what is tropmyosin
A protein found along the groove of the F-actin double helix
In which of the following situations does a resting membrane potential exist
A relaxed muscle fiber
Which of the following is true?
A threshold stimulus will cause contraction of a muscle fiber.
Your are hired to work in a laboratory ti measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle fibers undergoing contractions
ATP
Randy is participating in a strong man competition and is required to pull a yacht as far as he can. Which type of chemical process will his skeletal muscles rely on during this competition?
Anaerobic respiration
Which of the following will respond to a threshold stimulus with an all-or-none contraction
Both a single muscle fiber and a single motor unit are correct
which of the following statements regarding the sliding filament model is false
Both actin and myosin myofilaments shorten during contraction
A lack of glycol enzymes within skeletal muscle fibers would impair which type of
Both anaerobic respiration and aerobic respiration are correct
Alex is participating in a 50-meter dash. Predict the most important chemical process his muscles will rely on during this race.
Both anaerobic respiration and creatine phosphate breakdown are correct
which of the following situations occurs in electrically excitable cells
Deplorarization causes voltage- gated sodium ion channels to open
which of the following is true about skeletal muscle
Every muscle fiber receives a branch of an axon from the nerve
Incomplete tenus
Is the condition in which the muscle fiber only partially relaxes between contractions
The times between the application of the stimulus to a motor neuron and the beginning of contraction is called the ______ phase
Latent or log
Which of the following causes an unequal ion concentration across the resting plasma membrane
Negatively charged proteins not readily diffusing across the plasma membrane
Which of the following is true?
Optimal actin and myosin overlap will produce maximal contraction.
The outside of the resting plasma is ____________ relative to the inside of the resting plasma membrane
Positively charged
When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the
Power stroke
Arrange these structures as they participate in excitation- contraction
Sarcolemma, T tubules, sarcoplasmic reticulum, Ca2+
deploarization of the plasma membrane occurs when there is a rapid influx (inflow) of
Sodium ions
when comparing smooth and skeletal muscle cells, which of the following statements is true
The myofialments in smooth muscle do not form sacometers
Callie is a world class marathon runner. Which of the descriptions about her dominant type of skeletal muscle is FALSE?
They are well adapted to anaerobic activity
which of the following are NOT a property of the myosin head
They bind to troponin
which of the following statments concerning fast- twitch muscle fibers is true
They split ATP rapidly
aerobic respiration
Yields as many as 26 ATP per glucose molecule metaboilized
what is triad
a T tubule and two adjacent terminal cisternae
An eccentric contraction Is described as
a muscle produced tension, but the length of the muscle is increasing
An isotonic contraction is described as
a muscle produces constant tension during contraction.
A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions ic called
complete tetanus
T tubles
conduct action potentials deep into the muscle fiber
A proper definition of muscle tone is
constant tension produced by muscles for long periods of time
which of the following is NOT a function of skeletal muscle
constriction of organs
muscle myofibrils
contain myosin and actin myofilaments
actin myofilaments
contain strands of fibrous actin.
Lack of acetylcholinesterase in the synaptic cleft would result in
continuous stimulation of the postsynaptic membrane
A myofibril is the
contractile thread that extends the length of the muscle fiber
The capacity of a muscle cell to shorten forcefully is known as
contractility
Which of the following conditions in muscle fibers would contribute to muscle fatigue
depletion of ATP reserves
Acetylcholine binds to a membrane bound receptor and causes ligand- gated sodium channels to open and results in
depolarization
smooth muscle
depolarizes when both Na+ and Ca2+ diffuse into the cell
in smooth muscle most of the Ca+ needed for muscle contraction
enters from extracellular fluid
Betty took a fall and broke her arm, which required that she wear a cast for a prolonged period of time. When she took the cast off she was alarmed to see that her muscles
has undergone atrophy
Tetanus of a muscle is thought to be caused by
high Ca2+ concentrations in the sarcoplasm.
which of the followung statements concerning types of muscle contraction is false
in isometric contractions, the amount of tension produced by the muscle is constant
which of the following helps explain the increased tension seen in multiple wave summation
increased concentration of Ca2+ around the myofibrils
which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane
increased permeability of the membrane to Na+ and increased intracellular concentration of K+
Select the phrase that does not belong with the others
increased vascularity
the refractory period
is the time period which the tissue cannot respond again
identity the statement concerning the skeletal muscle that is true
it is responsible for locomotion
A by- product of anaerobic respiration in muscle fibers is
lacate
The length of the resting sarcomere is
longer than the length go a contacted sarcomere
Movements of the body are usually smooth and occur at differing rates because
motor units contract out of phase at their own particular rates
A sustained muscle contraction is known as
tetanus
Oxygen deficit represents
the amount of O2 that cells need to replenish ATP supplies after exercise.
what is a cross- bridge
the combination of myosin heads with active sites on actin molecules
The type of muscle fatigue known as "psychological fatigue" is the result of
the emotional state of an individual
What is the power stroke
the movement of myosin head while attached to actin myofilament
Concentric contractions occurs when
the muscle produced increasing tension as it shortens
concentric contraction is described as
the muscle produces increasing tension as it shortens.
increased strength of a trained muscle is due to
the nervous systemabilityy to recruit a large number of motor units simultaneously
Whole muscles can respond in a graded fashion to stimuli by varying
the number of motor units recruited
The plasma membrane of an excitable cell is more permeable to K+ because
there are more leak ion channels for K+ than Na+
myosin is also know as the
thick myofilament
which of the following is composed of myosin moleculesles
thick myofilaments
A muscle fiber will respond to a stimulus when that stimulus reaches the ______ level
threshold