WorksheetsExam 3- Muscular System
Total questions: 59
Worksheet time: 30mins
What actually does the shortening during contraction?
actin
myosin
muscle fiber
sarcomere
What happens to the filaments in accordance with the sliding filament theory?
they shorten
they move further away from each other
they do not move
they slide past each other
Which is correctly matched with its definition?
membrane potential- In resting state all cells have voltage across membrane
action potential- change or depolarization conducted along the membrane
action potential- In resting state all cells have voltage across membrane
membrane potential- change or depolarization conducted along the membrane
What steps must occur in order for a skeletal muscle to contract?
nerve stimulation
an action potential must be generated in sarcolemma
action potential must be propagated along sarcolemma
intracellular calcium levels must rise briefly
What are the parts of the neuromuscular junction?
axon terminal
junctional folds
synaptic cleft
myofilaments
What does the axon terminal have in it?
fluid
synaptic vesicles that contain ACh
calcium, sodium, and potassium
sarcolemma
What receptors are located in the junctional folds of the sarcolemma?
ACh receptors
Na+ receptors
K+ receptors
Ca2+ receptors
When the nerve impulse arrives at the axon terminal, what happens?
the muscle contracts
the action potential travels down the sarcolemma
ACh is released into the synaptic cleft
myofilaments slide past each other
What is end plate potential?
Generation and propagation of an action potential (AP)
reaching threshold
Restoration of resting conditions (resting membrane potential)
Localized depolarization at the NMJ caused by ACh release opening ligands
What does the generation and propagation of an action potential cause?
repolarization
depolarization
hyperpolarization
How is an action potential generated?
when membrane voltage reaches threshold, Na+ voltage-gated channels open
when membrane voltage reaches threshold, K+ voltage-gated channels open
When ACh receptors bind to the action potential
How is an action potential propagated?
the action potential spreads from voltage-gated K+ channel to the next
the action potential spreads from voltage-gated ACh channel to the next
the action potential spreads from voltage-gated Na+ channel to the next
What occurs during repolarization?
Restoration of the resting membrane potential
Generation and propagation of an action potential (AP)
Localized depolarization at the NMJ
i got too tired to make a 4th option :')
What is a refractory period?
muscle fiber cannot be stimulated for a specific amount of time
muscle fiber can be stimulated for a specific amount of time
the amount of time depolarization takes
the amount of time it takes to reach threshold
What must occur so repolarization can begin?
Na+ channels close
K+ channels open
Na+K+ Pump continue to pump to help restore resting conditions
ACh must be released onto sarcolemma
What occurs in excitation-contraction coupling?
Calcium binds to troponin
AP moves down T tubules to voltage sensitive proteins on SR
SR releases calcium
Calcium binds to tropomyosin
What happens when the neural impulse stops?
calcium is transported back to SR by ATP
tropomyosin and troponin move back into original positions
thin filament slides back into relaxed position
membrane potential is re-established by ion pumps along T-tubules
the membrane depolarizes
What is the force exerted on the load or object to be moved?
isometric contraction
isotonic contraction
muscle tension
motor unit
Match Isometric and isotonic contraction with their correct definitions?
isotonic- muscles shorten bc muscle tension exceeds load, movement occurs
isometric- no shortening; muscle tension increases but does not move load
isometric- muscles shorten bc muscle tension exceeds load, movement occurs
isotonic- no shortening; muscle tension increases but does not move load
What consists of the motor neuron and all muscle fibers?
sarcomere
motor unit
recruitment
load
What is the simplest contraction resulting from a muscle fiber’s response to a single action potential from motor neuron?
muscle twitch
muscle contraction
wave summation
temporal summation
What phase of the muscle twitch has no tension and is the events of excitation-contraction coupling?
period of relaxation
period of contraction
latent period
what even is that
What phase of a muscle twitch sees tension increase as the cross bridges forming?
period of relaxation
period of contraction
latent period
What phase of a muscle twitch sees tension decline back to 0 because calcium reenters the SR?
period of relaxation
period of contraction
latent period
What principle states stimulated muscles fibers contract completely, there are no particle contractions?
wave summation
all or none principle
temporal summation
recruitment principle
What results if 2 stimuli are received by a muscle in rapid succession?
unfused tetanus
fused tetanus
wave/temporal summation
graded potential
Match fused and unfused tetanus to their correct definitions
fused- looks like one big contraction cannot see a difference in stimuli
unfused- quivering contraction
unfused- looks like one big contraction, cannot see a difference in stimuli
fused- quivering contraction
What occurs when stimulus is sent to more muscle fibers, leading to more precise control?
load
summation
motor unit
recruitment
What motor units are recruited first?
largest
smallest
midsized
whats a motor unit
What types of stimulus are involved in recruitment?
maximal stimulus- strongest, increases maximum contractile force
minimal stimulus- weakest, decreases maximum contractile forces=
subthreshold- stimulus not strong enough to see contraction
threshold- strong enough to cause observable contraction
All of the following are functions of ATP in the muscle fiber EXCEPT
pump calcium back into SR
move and detach cross bridges
to force the muscle to contract
Pump Na+ out of and K+ back into cell after excitation-contraction coupling
Which pathway does not require oxygen, works faster but is less effective and forms lactic acid?
aerobic
anaerobic
Which pathway requires oxygen, works slower but is more effective?
aerobic
anaerobic
What is the physiological inability to contract despite continued stimulation?
load
recruitment
fatigue
tone
What are the factors of muscle contraction?
number of fibers stimulated
relative fiber size
frequency of stimulation
degree of muscle stretch
Velocity and duration of contraction depend on what
muscle fiber type
load
recruitment
genetics
What muscle fiber has high oxygen storage and slow ATP uses, very resistant to fatigue, low intensity endurance?
fast oxidative fibers
fast glycolytic fibers
slow oxidative fibers
slow glycolytic fibers
What muscle fiber has high oxygen storage but fast ATP use, medium resistance to fatigue, fit for jogging or sprinting?
fast oxidative fibers
fast glycolytic fibers
slow oxidative fibers
slow glycolytic fibers
Which fibers produce ATP anaerobically, easily fatigued, used for intense powerful movements (short bursts)?
fast oxidative fibers
fast glycolytic fibers
slow oxidative fibers
slow glycolytic fibers
Aerobic exercise leads to increased
myoglobin synthesis
# of mitochondria
muscle fatigue
muscle capillaries
Resistance exercise like weightlifting causes
muscle hypertrophy
muscle atrophy
increase in breathing rate
increase in resting heart rate
Which of the following is correctly ordered smallest to largest?
myofibril, sarcomere, fascicle, fiber, muscle
myofilament, sarcomere, myofibril, fiber, fascicle, muscle
myofilament, fascicle, myofibril, fiber, sarcomere, muscle
muscle, fascicle, fiber, myofibril, sarcomere, myofilament
Which type of muscle is voluntary and striated?
cardiac
smooth
hard
skeletal
Where can the perimysium be found?
surrounding fascicles
surrounding the whole muscle
surrounding myofilaments
surrounding the sarcomere
What stores oxygen and gives muscles their red pigment?
hemoglobin
myoglobin
carotene
sarcoplasmic reticulum
What is the function of the sarcoplasmic reticulum?
store potassium
store sodium
store calcium
store ACh
What must be released from the axon terminal in order to generate the end plate potential?
Na+
K+
ACh
Ca+
What is end plate potential?
a local depolarization of the neuromuscular junction
a full depolarization
hyperpolarization
repolarization
What channels are open during depolarization?
K+
Cl+
Na+
ACh
What must bind to troponin to move tropomyosin off of the binding sites?
Ca+
Na+
K+
Cl-
What is the all or none principle?
only partial contractions, never full ones
the muscles always are allowed to twitch
all muscles are allowed to contract, or none of them are
all muscle fibers contract completely, or not at all
A quivering contraction would be...
complete tetanus
fused tetanus
unfused tetanus
not wave summation
Which of the following does not influence velocity and duration of a contraction?
muscle fiber type
recruitment
load
wave summation
Where is calcium being released from during excitation-contraction coupling?
sarcolemma
sarcomere
sarcoplasmic reticulum
sarcoplasm
What is a fascicle?
a bundle of muscle fibers
the surrounding portion of a whole muscle
a muscle cell
the structure providing nutrients to muscles
Which of the following is the correct order of the connective tissue sheaths?
epimysium -> perimysium -> endomysium
perimysium -> epimysium -> endomysium
endomysium -> perimysium -> epimysium
epimysium -> endomysium -> perimysium
Which muscle attachment is the attachment on the moveable bone?
origin
insertion
Tendons and aponeurosis' are examples of what type of attachment
direct
indirect
What is the action of Z-discs during contraction?
shorten
disappear
move closer to each other
get pulled towards the M-line
