Transcript Should Dane county allow ATC to put up a new transmission

Physiology Review
(ppt modified from http://www.recreation.ucsb.edu/ess/ess40/chap8.htm)
The SARCOMERE
is the functional
unit of the muscle.
A sarcomere is
found between
two Z lines.
The Muscle Fiber Is Composed of
Special Contractile Proteins
• Myosin is the main, thick structural protein in the
sarcomere. It has cross bridges for attaching to
the Actin protein.
• Actin is the main, thin structural protein in the
sarcomere. Each actin molecule has a binding site
that can attach with a Myosin cross bridge.
• Actin and myosin are contractile proteins.
Tropomyosin and Troponin Are
Regulatory Proteins.
These regulatory proteins control the
muscle contraction process.
• They either allow or block actinmyosin interaction depending on
their configuration.
TROPOMYOSIN
• Tropomyosin covers the actin
binding sites.
• This prevents the union of actin
with myosin cross bridges.
TROPONIN
• Troponin has three binding sites:
– one binds to Tropomyosin, one to Actin, and
one to Ca+ ions.
– When calcium combines with troponin,
tropomyosin slips away from its blocking
position between actin and myosin.
– With this change actin and myosin can
interact and muscle contraction can occur.
•
fig.cox.miami.edu/.../150/neuro/tropomyosin.jpg
Sliding Filament Mechanism
• The myosin cross bridges can bind to
the actin.
• After binding the thin (actin)
filaments are pulled toward the
center of the sarcomere.
• This is known as the Sliding Filament
Mechanism.
•
http://people.eku.edu/ritchisong/crossbridge3.gif
SLIDING FILAMENT MECHANISM
• Neither the thick nor thin
filaments change in length. They
change their position with one
another.
• The actin slides closer together
between the thick filaments.
•
http://3dotstudio.com/contract.gif
• The myosin cross bridges pull the thin
actin filaments inward.
• A single power stroke pulls the actin
inward only a small percentage of the total
distance.
• Complete shortening occurs by repeated
cycles of the power stroke.
• The link between myosin and actin is
broken at the end of one cross bridge
cycle. A cross bridge returns to its original
position and can connect to the next actin
molecule position, pulling the actin
filament further.
www.octc.kctcs.edu
Muscle contraction
• The process starts when the muscle cell is depolarized
• A neuron sends action potentials to muscle fibers.
• This neuron releases acetylcholine at the neuromuscular
junction.
• This produces an action potential over the entire muscle
cell membrane.
– Sodium/Potassium pumps are not working when Ach is on the
receptors of muscle cells…chaos ensues!
The Release of Calcium Ions from the
sacroplasmic reticulum starts the Sliding
Process.
• Calcium from the SR binds with troponin.
• By this event, tropomyosin is pulled off the
binding sites of actin
• This allows the myosin cross bridges to
bind to actin and slide this protein.
Test Information…
• 60 points total
–20 Anatomy ID—real people,
pictures and microscope slides
–Some anatomy on Physiology
portion
• Body movements
• Draw a line drawing of sarcomere
Name this muscle
Muscle?
Muscle?
Notecardable items…
• Fill in the blank (with words provided) of
body movements (4)
• Two short answers have choices…choose the
question you can answer the MOST completely.
– A diagnostic vs. muscle connections
– Mitochondria’s role in contraction vs blood
supply
Short Answer Questions
(notecardable…)
• Explain the protein alignment within a
sarcomere. Draw a diagram as well…
Short Answer Questions
(notecardable…)
• Physiology of muscle cell—broken
into 5 questions
– Three phases of function of MC
– Function of neuromuscular junction
– Stimulation in detail
– Contraction in detail
– Mechanism for lengthening
Short Answer Questions
(notecardable…)
• Antagonistic/Synergistic as it relates
to function of muscles
• Difference between strains, sprains
and contusions
• Three factors contributing to muscle
aging
• Steroid question—what have you
learned about the pros/cons/debate?