Question 1
Explain the primary differences between
smooth, skeletal, and cardiac muscle tissue
Skeletal muscle fibers are cylindrical, multinucleate cells,
and are the largest fibers of the three types
Smooth muscle - no striations and is involuntary found in
the wall of hollow organs (viscera)
Cardiac muscle - found only in the heart; arranged in spiral
or figure 8 shaped bundles joined by intercalated discs
Question 2
Describe how striations make up the
arrangement of skeletal muscle tissue
Due to the alternating dark and light bands
within the sarcomere.
Question 3
What 3 words are used to describe
skeletal muscle tissue?
Striated
Skeletal
voluntary
Question 4
What 3 words are used to describe
cardiac muscle tissue?
Cardiac
Striated
involuntary
Question 5
What are 3 prefixes that indicate they
apply to muscle tissue?
Myo
Mys
Sarco
Question 6
How do the postural muscles work?
Make constant, tiny adjustments as needed
They function almost continuously
Question 7
What is the role of the sarcolemma in relation
to muscle contraction?
To act as the “plasma membrane” and
function to act as a semi-permeable
membrane to the muscle
Question 8
Draw and label the parts of an individual
sarcomere.
Question 9
Explain the roles of the following:
Sarcoplasmic reticulum (SR), Thin filament
Thick filament
SR – smooth ER to store and release Calcium
Thin – anchored to the Z line and is the
filament that slides during contraction
Thick – forms crossbridges to attach to actin
during the power stroke phase of
contraction
Question 10
Where are the following areas on a
sarcomere?
H zone, M line, Z line, A band, I band
Question 11
Define and label the following:
Synaptic cleft, Synaptic vesicles, T-tubules
Question 12
Explain the effect an action potential would
have on a relaxed muscle.
Change the permeability of the sarcolemma
to sodium causing an influx of + ions
generating an AP causing Ca+ to be released
from the SR
Question 13
How do the crossbridges on a myosin filament
work? What is needed so they can function?
They link to the actin causing the sliding of the
thin filament. Need active site exposure
Question 14
What impact does acetylcholine have on a
muscle? What is the effect of troponin and
tropomyosin?
ACh – is the neurotransmitter making what
was electrical, become chemical so it can
ignite another AP
Troponin – actin protein that Ca+ binds to
causing a change in the filament
Tropomyosin – actin protein that covers up
the active (binding) sites on actin preventing
the crossbridges from forming
Question 15
What energy source is needed to cause the
filament to slide and produce a muscle contraction?
What does it convert to when energy is released?
ATP is the energy source
Converts to ADP + Pi when coupled with
hydrolysis
Question 16
What is the role of Sodium on muscle
contraction? Explain its location before and
during a contraction.
Sodium changes the polarity of the
sarcolemma leading to an AP on the muscle
due to its positive charge
Question 17
Explain each and include the electrical conditions:
Polarization, Depolarization, Repolarization
Polarization – at rest; Na on outside, K inside
Depolarization – Na rushes inward, K out
changing the polarity of the sarcolemma
Repolarization – restores the muscle to its
previous condition of rest in a wavelike fashion
Question 18
Identify when Calcium is released and the effect it
produces on a muscle
Ca+ binds to troponin which moves the
tropomyosin off the active or binding sites
on the actin preparing the myosin to begin
crossbridge formation