Physiology Review

1
Physiology Review

• The SARCOMERE is the functional unit of the
  muscle.
• A sarcomere is found between two Z lines.

2
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 cellschaos ensues!

3
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 cellremember the pumps
  arent working when Ach is docked on the
  sarcolemma!
• This influx of Na ions causes the Sarcoplasmic
  Reticulum to release its Ca2 into the muscle
  cell.

4
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.

5

• http//people.eku.edu/ritchisong/crossbridge3.gif

6
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.

7

• The muscle cell is made up of Contractile
  proteins and Regulatory proteins

8
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.

9
Regulatory Proteins

• Tropomyosin and Troponin are regulatory proteins
  and control the muscle contraction process.
• They either allow or block actin-myosin
  interaction depending on their configuration.

10

• fig.cox.miami.edu/.../150/neuro/tropomyosin.jpg

11
TROPOMYOSIN

• Tropomyosin covers the actin binding sites.
• This prevents the union of actin with myosin
  cross bridges in a relaxed muscle cell.

12
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.

13

• http//3dotstudio.com/contract.gif

14
(No Transcript)
15
www.octc.kctcs.edu
16
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

17
Relaxation

• Once there is less Na inside the cell, the
  sarcoplasmic reticulum will resorb the Ca2 that
  it released.
• Ca2 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 its original
  length.

18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Name this muscle
22
Muscle?
23
Muscle?
24
Test Information

• 58 points total (min of 35)
• 20 Anatomy IDreal people, pictures and
  microscope slides
• Some anatomy on Physiology portion
• Body movements
• Draw a line drawing of sarcomere

25
Notecardable items

• Fill in the blank (with word bank) of body
  movements
• One short answer has choiceschoose the question
  you can answer the MOST completely.
• Mitochondrias role in contraction
• blood supply in muscle cells

26
Notecardable items

• Steroid questionwhat 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 loopeither
• Shaking someones hand
• Kicking a soccer ball

27
Short Answer Questions(notecardable)

• Explain the protein alignment within a sarcomere.
  Draw a diagram as well

28
Short Answer Questions(notecardable)

• Physiology of muscle cellbroken 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)

29
Short Answer Questions(notecardable)

• Antagonistic/Synergistic as it relates to
  function of muscles
• All three disordersmake sure you know them!
• Fibromyalgia (muscles?symptoms?treatments?)
• MDcomplications
• Cachexia (3 factors that contribute)
• Case study