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

Physiology Review
The SARCOMERE
is the functional
unit of the muscle.
A sarcomere is
found between
two Z lines.
Neural Stimulation
• Phase 1 of Muscle Physiology: The process starts when the
muscle cell is depolarized
• A neuron (nerve cell) releases acetylcholine at the
neuromuscular junction.
• This produces an action potential over the entire
sarcolemma. (This is called an action potential because if
there is enough Ach released, it has the potential to cause
contraction of the muscle)
– Sodium/Potassium pumps cannot work when Ach is on the
receptors of muscle cells…chaos ensues!
Muscle Contraction
• Phase 2 of Muscle Physiology: The process starts
when Ach docks on the sarcolemma.
• Ach causes Na+ ions to rush INTO the cell and K+
ions to rush OUT of the cell—remember the pumps
aren’t working when Ach is docked on the
sarcolemma!
• This influx of Na+ ions causes the Sarcoplasmic
Reticulum to release it’s Ca+2 into the muscle cell.
Muscle Contraction
The release of Calcium ions from the sacroplasmic
reticulum starts the Sliding Process.
• Calcium from the SR binds with troponin.
• Tropomyosin is pulled off the binding sites
of actin
• This allows the myosin cross bridges to
bind to actin and slide the actin toward the
center of the cell.
•
http://people.eku.edu/ritchisong/crossbridge3.gif
SLIDING FILAMENT MECHANISM
• Neither the Myosin nor the actin
filaments change in length. They
change their position with one
another.
• The actin slides between the
myosin.
The muscle cell is made up of Contractile
proteins and Regulatory proteins
Contractile Proteins
• Myosin is the main, thick protein in the sarcomere.
It has cross bridges for attaching to the Actin
protein and is found in center of cell.
• Actin is the main, thin protein in the sarcomere.
Each actin molecule has a binding site that can
attach with a Myosin cross bridge and is found
attached to the z-lines.
Regulatory Proteins
Tropomyosin and Troponin are
regulatory proteins and control the
muscle contraction process.
• They either allow or block actinmyosin interaction depending on
their configuration.
•
fig.cox.miami.edu/.../150/neuro/tropomyosin.jpg
TROPOMYOSIN
• Tropomyosin covers the actin
binding sites.
• This prevents the union of actin
with myosin cross bridges in a
relaxed muscle cell.
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.
•
http://3dotstudio.com/contract.gif
www.octc.kctcs.edu
Relaxation
• Phase 3 of Muscle Physiology: The process starts
when the muscle cell is repolarized
• A neuron (nerve cell) stops releasing acetylcholine
at the neuromuscular junction.
• If there is no more Ach, the Na+/K+ pumps can do
their work again and will start re-establishing the
status quo of more Na+ outside the cell and more K+
inside the cell
Relaxation
• Once there is less Na+ inside the cell, the
sarcoplasmic reticulum will resorb the Ca+2 that it
released.
• Ca+2 will release from the troponin, causing it to
“spring” back up and the tropomyosin to block the
actin/myosin binding site once again.
• Contraction will stop
• The contraction of ANTAGONISTIC muscle fibers
are necessary to pull the sarcomere to it’s original
length.
Name this muscle
Muscle?
Muscle?
Test Information…
• 58 points total (min of 35)
–20 Anatomy ID—real people,
pictures and microscope slides
–Some anatomy on Physiology
portion
• Body movements
• Draw a line drawing of sarcomere
Notecardable items…
• Fill in the blank (with word bank) of body
movements
• One short answer has choices…choose the
question you can answer the MOST completely.
– Mitochondria’s role in contraction
– blood supply in muscle cells
Notecardable items…
• Steroid question—what are they, what
effects do they have on the human body,
what debate is there as to effectiveness?
• How do muscles attach inside the body?
To each other? To bones?
• One feedback loop—either
– Shaking someone’s hand
– Kicking a soccer ball
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 (# in order)
– Contraction in detail (# in order)
– Relaxation in detail (# in order)
Short Answer Questions
(notecardable…)
• Antagonistic/Synergistic as it relates to
function of muscles
• All three disorders—make sure you know
them!
– Fibromyalgia
(muscles?symptoms?treatments?)
– MD—complications
– Cachexia (3 factors that contribute)
• Case study