Muscles Flashcards
A skeletal muscle organ is covered by connective tissue called:
Ectomysium
Perimysium
Intramysium
Endomysium
Epimysium
Epimysium
The heads of the myosin filaments are associated with an enzyme called ATP synthase.
False
A group of muscle cells is covered by connective tissue called:
Ectomysium
Endomysium
Epimysium
Intramysium
Perimysium
Perimysium
In general, when something binds to a three-dimensional protein, it changes the shape of that protein.
True
What triggers the change in the 3D shape of troponin?
The shortening of the sarcomere.
Cross-bridging.
The binding of more calcium ions.
The sliding of the myofilaments.
The binding of more calcium ions.
A thin filament consists of all of the following proteins, except:
Myosin
Troponin
Actin
Tropomyosin
Myosin
Which of these is NOT a part of the actin myofilament?
tropomyosin
actin
cisternae
troponin
Cisternae
The function of the linear tropomyosin molecule is to block the active sites on the thin filaments.
True
The enlarged sac-like areas of the sarcoplasmic reticulum that abut the T tubules are called:
terminal cisternae.
tropomyosin molecules.
sarcomeres.
sarcolemma.
troponin molecules.
Terminal cisternae
Muscle tissue that maintains our body posture is:
Cardiac muscle tissue
Skeletal muscle tissue
Smooth muscle tissue
Skeletal muscle tissue
True or False: The H zone functions in anchoring the thick filaments.
False
A fascicle is covered by connective tissue called:
Epimysium
Endomysium
Sarcoplasm
Sarcolemma
Perimysium
Perimysium
True or False: When myoblasts fuse in the embryo, a syncytium, called a skeletal muscle cell is formed.
True
True or False: The H zone is found inside of the I band.
False
Muscle tissue is unique because it is excitatory (can conduct electrical signals):
False
True or False: Striated muscle tissues include skeletal and cardiac muscle tissues.
True
Muscle tissue found in the walls of blood vessels is:
Smooth muscle tissue
Cardiac muscle tissue
Skeletal muscle tissue
Smooth muscle tissue
True or False: Striations are formed by the alternating light A bands and dark I bands
False
During muscle contraction, cross bridges form where myosin heads come in contact with active sites on:
Question 19 options:
troponin molecules.
calcium ions.
acetylcholine molecules.
tropomyosin molecules.
actin molecules.
Actin molecules
True or False: Endomysium covers the sarcolemma:
True
Select the smallest structure in the muscle fiber:
Sarcomere Fascicle Fibril Filament Fiber
Filament
When skeletal muscle fibers hypertrophy, they:
Split in half.
Replicate.
Increase protein synthesis to increase their size.
Go through mitotic divisions.
Increase protein synthesis to increase their size.
We get bulkier from working out because skeletal muscles:
Question 3 options:
Increase protein synthesis to increase their size.
Go through mitotic divisions.
Replicate.
Split in half.
Increase protein synthesis to increase their size.
True or False: Myosin filaments contain the active sites to which the heads will bind during contraction.
False
True or False: The function of the sarcoplasmic reticulum is to store large amounts of sodium and potassium ions.
False
Muscle tissue that helps with the stability of our joints is called:
Smooth muscle tissue
Skeletal muscle tissue
Cardiac muscle tissue
Skeletal muscle tissue
The cell membrane of a muscle cell is called:
Endomysium Epimysium Sarcoplasm Perimysium Sarcolemma
Sarcolemma
Which of these units contains overlapping actin and myosin myofilaments in a relaxed sarcomere?
Z disk I band A band H zone M line
A band
Select the largest structure in the muscle fiber:
Fascicle
Filament
Fibril
Fiber
Fibril
True or False: Voluntary muscle tissues include smooth and skeletal muscle tissues.
False
Gap junctions in cardiac muscle tissue function as zippers between muscle cells to ensure that the heart contracts as a whole:
False
True or False: Skeletal muscle tissue is poorly innervated.
False
True or False: When more calcium ions bind to one of the subunits of the troponin complex, the whole troponin complex changes its 3-D shape.
True
The cytoplasm of a muscle cell is called:
Sarcoplasm
Sarcoplasmic reticulum
Sarcolemma
Sarcomere
Sarcoplasm
Skeletal muscle fibers cannot replicate because:
They have too many proteins.
They are striated.
They have too many nuclei.
They have too many satellite cells surrounding them.
They have too many nuclei
The interior of muscle fibers is mostly filled with:
sarcoplasmic reticulum. triads myofibrils. fascicles nuclei.
Myofibrils
This muscle tissue is always multinucleated.
Cardiac muscle tissue
Skeletal muscle tissue
Smooth muscle tissue
Skeletal muscle tissue
True or False: Terminal cisternae are part of the sarcoplasmic reticulum.
True
True or False: The M line runs through the middle of thick filaments in a sarcomere
True
The subunits of the troponin complex include all of the following, except:
the subunit that binds with tropomyosin
the subunit that binds with actin
the subunit that binds with calcium ions
the subunit that binds with myosin
The subunit that binds with myosin
The heads in skeletal muscle cells are always ready to bind and form cross-bridges.
True
When threshold voltage is reached on a skeletal muscle cell membrane, it triggers the opening of Na+ ____ -gated channels and K+ ____-gated channels.
Chemical, voltage
Chemical, chemical
Voltage, chemical
Voltage, voltage
Voltage, voltage
When the sarcolemma returns to electrical resting conditions, it ____.
Repolarizes
Depolarizes
Polarizes
Repolarizes
When more and more motor units are engaged to increase the strength of a muscle contraction, _____ occurs.
complete tetanus
spatial summation
temporal summation
wave summation
Spatial summation
During passive sodium ions always flow ____ a cell, and potassium ions always flow ___ of a cell.
into, out of
out of, into
Into, out of
True or False: When your patient does not have a sufficient amount of acetylcholine receptors, she will suffer from muscle paralysis.
True
When threshold voltage is reached, a change in the RMP of about +15 to +20 ____ (unit) occurs.
millivolts
amperes
watt
volts
Millivolts
Resistance exercise will most likely cause muscle to __________.
dystrophy
atrophy
hypertrophy
hypotrophy
Hypertrophy
A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band.
False
A sarcomere extends from:
Z disc to Z disc I band to I band H band to H band A band to A band M line to M line
Z disc to Z disc
When all end plate potentials start to merge on the motor end plate, a process called ____ occurs.
Summation
Propagation
Firing
Summation
Skeletal muscle is said to be a ____ muscle because we can control it consciously.
excitable
contractile
voluntary
striated
Voluntary
True or False: Ions are pumped non-stop across cell membranes through ion pumps.
True
When an AP arrives at an axonal terminal, Ca++ ____ -gated ion channels in the axonal terminal’s cell membrane are triggered to open.
voltage
pump
chemical
ligand
Voltage
What is the correct function for triads in skeletal a:
The triad synthesizes ATP.
The triad maintains the resting membrane potential.
The triad allows for Ca2+ release when a muscle fiber is excited.
The triad removes acetylcholine from the synaptic cleft.
The triad stores sodium.
The triad allows for Ca2+ release when a muscle fiber is excited.
True or False: Aerobic respiration produces more ATPs per glucose molecule than glycolysis does.
True
Calcium ion pumps are found in axonal terminals as well as in the membranes of terminal cisternae.
True
As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle depends mostly on __________.
temporal summation
wave summation
motor unit recruitment
Motor unit recruitment
Which structures interconnect myosin filaments and Z discs?
T tubule myofibril elastic filament sarcolemma thin filament
Elastic filament
When an action potential recreates itself over and over and really fast down an axon or down a T-tubule, it is said to:
Fire
Summate
Propagate
Propagate
This is a striated tissue with many flattened nuclei under the plasma membrane in each cell.
smooth muscle
visceral muscle
cardiac muscle
skeletal muscle
Skeletal muscle
True or False: Skeletal muscle fibers can be up to a foot long
True
The endomysium is a delicate connective tissue sheath that covers:
entire skeletal muscle organs
skeletal muscle fibers
bundles of smooth muscle fibers
bundles of cardiac muscle fibers
fascicles
Skeletal muscle fibers
The smooth endoplasmic reticulum of a muscle cell is called:
Sarcomere
Sarcolemma
Sarcoplasm
Sarcoplasmic reticulum
Sarcoplasmic reticulum
True or False: Satellite cells are located outside the skeletal muscle cells
True
True or False: Muscles are sometimes directly connected to bones, without a tendon:
True
Intercalated discs are characteristic for:
Skeletal muscle tissue
Smooth muscle tissue
Cardiac muscle tissue
Cardiac Muscle tissue
True or False: T-tubules wrap around individual myofilaments.
False
True or False: The term “syncytium” literally means many cells together.
True
True or False: Skeletal muscle is poorly vascularized
False
True or False: All hollow organs have smooth muscle in their walls
False
True or False: In a sarcomere of a skeletal muscle fiber, each thick filament is surrounded by 6 thin filaments (You may have to do some research on this).
True
True or False: The gap junctions in cardiac muscle tissue ensure that electrical currents pass rapidly between the muscle cells of the heart:
True
True or False: Ligaments connect muscle to bone
False
True or False: A thin filament is made up of a couple hundred myosin molecules.
False
The T in T-tubule stands for:
Triad
Tiny
Transverse
Terminal
Transverse
Excitability is a functional feature for the following:
Muscle and nervous tissues
Connective and epithelial tissues
Nervous and epithelial tissues
Muscle and connective tissues
Muscle and nervous tissues
True or False: Skeletal muscle fibers are very rich in mitochondria:
True
Muscle tissue that is attached to our bones is:
Cardiac muscle tissue
Smooth muscle tissue
Skeletal muscle tissue
Skeletal muscle tissue
The heads of the myosin filaments are associated with an enzyme that catalyzes ATP hydrolysis.
True
When acetylcholine binds to its receptors in the neuromuscular junction:
Sodium ions move out and potassium ions flow into the muscle fiber.
Ca2+ ions enter the T tubules.
The sarcolemma starts to repolarize.
The inhibitory effect of acetylcholinesterase is overridden.
The permeability of the sarcolemma to Na+ and K+ increases.
The permeability of the sarcolemma to Na+ and K+ increases
When calcium ions collide with _____ on the _____ filament in skeletal muscle cells, this protein complex changes its 3D shape.
Question 2 options:
troponin, myosin
tropomyosin, myosin
troponin, actin
tropomyosin, thick
Troponin actin
True or False: A skeletal muscle suspended in the lab will contract more forcefully during wave summation when a higher and higher voltage stimulus is applied to the suspended muscle in the lab:
False
Why do you continue to breathe so heavily after running from your car to the doctor’s office because you thought you were quite late?
The kidneys require oxygen to dispose of excess lactate.
Myosin heads need more oxygen to fully detach from actin.
The lungs can’t stop breathing until the heart rate slows down.
The body requires more oxygen to restore levels of ATP and creatine phosphate.
The body requires more oxygen to restore levels of ATP and creative phosphate
How many muscle fibers stimulate one somatic motor neuron? 3 2 0 1 4
0
After threshold voltage is reached, an action potential ____ when the first sodium channels open.
Question 6 options:
Stops
Propagates
Polarizes
Fires
Fires
Extensibility refers to the ability of a muscle to stretch.
True
Lactic acid produced by skeletal muscle does all of the following, EXCEPT:
Is mostly converted to pyruvic acid that can be used in the Krebs cycle.
Slows down enzymes and ion pumps in muscle cells.
Enters the blood stream
Might dissociate into water and carbon dioxide.
Causes muscle soreness
Causes muscle soreness
Pick the INCORRECT answer. Skeletal muscle tone:
Results from spinal reflexes.
Does not have a significant purpose in the body.
Ensures we do not slip out of our chair.
Is defined as the slightly contracted state of skeletal muscles even when we perceive them as relaxed.
Stabilizes joints and ensures muscles are always “ready” to respond.
Does not have a significant purpose in the body
The minimum stimulus needed to cause muscle contraction is called the __________.
latent period
innervation
motor unit
twitch
threshold
Threshold
Components of skeletal muscle fiber triads include:
two thick myofilaments and one thin myofilament
two thin myofilaments and one thick myofilament
two terminal cisternae and one T tubule
two A bands and one I band
two T tubules and one terminal cistern
Two terminal cisternae and one T tubule
A somatic motor neuron plus all its skeletal muscle fibers equals:
A sarcomere
A neuromuscular junction
A motor unit
A motor unit
For quick bursts of small amounts of ATP production, skeletal muscles depend on the enzyme creatine kinase.
True
True or False: In skeletal muscle cells, attached heads can bend by using the energy from an earlier ATP dehydration reaction.
False
When ACh binds in skeletal muscle, its protein receptors respond by opening their ____-gated ion channels.
pump
voltage
chemical
electrical
Chemical
If numerous nerve stimuli arrive at a muscle fiber so that the fiber cannot relax in between twitches, the muscle fiber is:
fatigued
spasming
in complete tetanus
In complete tetanus
Ca++ ions follow their concentration gradient and flow ___ an axonal terminal when the proper ion channels are triggered to open.
into
out of
Into
Upon arrival in the T-tubules, the AP triggers the opening of ____ ion channels in the membranes of the terminal cisternae.
phosphate
sodium
potassium
calcium
Calcium
Where do thick and thin filaments overlap?
In the Z discs
In the I band
In the M line
In the A band
In the H band
In the A band
Once the first few voltage-gated Na+ ion channels have opened during an action potential, it triggers the opening of more and more. This is an example of a ____ mechanism.
negative feedback
positive feedback
Positive feedback
_____ release neurotransmitters into the synaptic cleft.
terminal cisternae sarcolemma junctional folds synaptic vesicles Sarcoplasmic rectilium
Synaptic vesicles
When calcium ions trigger the formation of ____ in skeletal muscle, the muscle starts to tense.
Hydroxyapatites
Synaptic vesicles
Depolarization
Cross-bridges
Cross-bridges
True or False: An isometric contraction does not change muscle length.
True
If a poison blocks acetylcholinesterase at a neuromuscular junction, what are the consequences?
numbness muscle wasting tetanus atrophy flaccid paralysis
Tetanus
True or False: The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber.
True
Striated muscle tissues include:
Cardiac and skeletal
All muscle tissues
Smooth and skeletal
Only skeletal
Cardiac and skeletal
When a muscle twitch produces enough tension to move an object by shortening the muscle, the twitch is in the _____ phase.
relaxation
latent
twitch
contraction
Contraction
True or False: A skeletal muscle suspended in the lab will contract more forcefully during wave summation when a threshold stimulus of the exact same strength is applied over and over, and very fast in a row.
True
True or False: Most ATP production in skeletal muscle cells results from anaerobic metabolism.
False
What is NOT a function of “repaying” oxygen debt?
To replenish pyruvic acid. To neutralize carbon dioxide buildup To replenish ATP reserves To regenerate glycogen To restore resting levels of ATP and CP
To neutralize carbon dioxide buildup
A skeletal muscle suspended in the lab will contract more forcefully during motor unit recruitment when a higher and higher voltage stimulus is applied to the suspended muscle in the lab:
True
Shortening a muscle while it maintains constant tension is called __________.
an isotonic contraction
an isokinetic contraction
an isometric contraction
Isotonic contraction
Calcium ions move ______ their concentration gradient from the _____ into the ____ of the muscle fiber.
Against, sarcoplasm, terminal cisternae
Down, terminal cisternae, sarcoplasm
Down, sarcoplasm, terminal cisternae
Against, terminal cisternae, sarcoplasm
Down, terminal cisternae, sarcoplasm
Calcium ion pumps move calcium ions ____ their concentration gradient ____ axonal terminals and _____ terminal cisternae.
against, out of, into
against, into, into
along, out of, into
along, into, into
Against, out of, into
What happens to a muscle fiber when acetylcholinesterase outlasts the release of acetylcholine at its neuromuscular junction? The muscle fiber:
opens its Na+ channels
releases Ca2+
relaxes
contracts
gets stronger
Relaxes
When we stretch our skeletal muscles, __________ in the protective connective tissue layers helps resist excessive stretching and subsequent injury to the muscle.
actin
thick filaments
collagen
Titin filaments
Collagen
When neurotransmitters follow their concentration gradients across a synaptic cleft, they are going through the process of:
Active transport
Exocytosis
Osmosis
Simple diffusion
Simple diffusion
Which of the following individuals would have more mitochondria in her skeletal muscle?
A 50-year-old sedentary computer programmer A 22-year-old soccer player A long-term hospice patient A model on a reduced-calorie diet
A 22 year old soccer player
Suppose a muscle fiber cannot fully relax in a lab environment because we keep applying threshold stimuli of the same strength really fast, what will the fiber experience?
complete tetanus
spatial summation
fatigue
spasm
Complete tetanus
Once an AP has fired, it is unstoppable and will travel really fast by following the sarcolemma down into ____.
sarcoplasmic reticulum
T-tubules
the axon
axonal terminals
T-Tubules
When your patient does not have a sufficient amount of acetylcholine receptors, she will suffer from muscle paralysis.
True
Once an AP has fired, it is unstoppable and will travel really fast by following the sarcolemma down into ____.
the axon
axonal terminals
sarcoplasmic reticulum
T-tubules
T-tubules
Skeletal muscles depend on ATP to function, but can operate in both O2 rich and O2 poor situations.
True
When a muscle twitch produces enough tension to move an object by shortening the muscle, the twitch is in the _____ phase.
relaxation
contraction
twitch
latent
Contraction
How many muscle fibers stimulate one somatic motor neuron?
3
2
0
4
1
0
Extensibility refers to the ability of a muscle to stretch.
True
If a poison blocks acetylcholinesterase at a neuromuscular junction, what are the consequences?
flaccid paralysis
tetanus
muscle wasting
numbness
atrophy
Tetanus
What happens to a muscle fiber when acetylcholinesterase outlasts the release of acetylcholine at its neuromuscular junction? The muscle fiber:
Question 8 options:
opens its Na+ channels
contracts
relaxes
gets stronger
releases Ca2+
Relaxes
True or False: Active sites in skeletal muscle cells are always ready to participate in cross-bridges.
False
Suppose a muscle fiber cannot fully relax in a lab environment because we keep applying threshold stimuli of the same strength really fast, what will the fiber experience?
fatigue
complete tetanus
spatial summation
spasm
Complete tetanus
When ACh binds in skeletal muscle, its protein receptors respond by opening their ____-gated ion channels.
voltage
chemical
electrical
pump
Chemical
When all end plate potentials start to merge on the motor end plate, a process called ____ occurs.
Propagation
Firing
Depolarization
Summation
Summation
When acetylcholine binds to its receptors in the neuromuscular junction:
The sarcolemma starts to repolarize.
Ca2+ ions enter the T tubules.
Sodium ions move out and potassium ions flow into the muscle fiber.
The permeability of the sarcolemma to Na+ and K+ increases.
The inhibitory effect of acetylcholinesterase is overridden.
The permeability of the sarcolemma to Na+ and K+ increases.
_____ release neurotransmitters into the synaptic cleft.
sarcolemma
terminal cisternae
junctional folds
synaptic vesicles
sarcoplasmic reticulum
Synaptic vesicles
After ACh binds, the polarity of the sarcolemma reverses. This process is called _____ and generates a ____ potential.
repolarization, end plate potential
depolarization, graded potential
polarization, action potential
hyperpolarization, resting potential
Depolarization, graded potential
For quick bursts of small amounts of ATP production, skeletal muscles depend on the enzyme creatine kinase.
True
During passive sodium ions always flow ____ a cell, and potassium ions always flow ___ of a cell.
into, out of
out of, into
Into, out of
When an AP arrives at an axonal terminal, Ca++ ____ -gated ion channels in the axonal terminal’s cell membrane are triggered to open.
chemical
ligand
pump
voltage
Voltage
In skeletal muscle, after ACh binds to the motor end plate, both _____ and _____ ions follow their concentration gradients through the same ion channels.
sodium and potassium
calcium and potassium
calcium and phosphate
calcium and sodium
Sodium and potassium (?)
The minimum stimulus needed to cause muscle contraction is called the __________.
motor unit
twitch
threshold
innervation
latent period
Threshold
______ catalyzes the transfer of a free phosphate from CP to ADP.
Question 3 options:
myokinase
creatine kinase
ATP
creatinine
cAMP
Creatine kinase
When synaptic vesicles fuse with an axonal terminal’s cell membrane, they go through the process of:
phagocytosis
endocytosis
exocytosis
pinocytosis
Exocytosis
Fibers of either one of the three muscle tissues will respond to an electrical stimulus because all muscle cells are _________.
excitable
striated
involuntary
contractile
Excitable
