Download Energy for Muscle Contraction • Initially, muscles used stored for

Energy for Muscle Contraction
• Initially, muscles used stored
for energy
• Bonds of ATP are broken to release energy
• Only 4-6 seconds worth of ATP is stored by muscles
• After this initial time, other pathways must be utilized to produce ATP
Muscle Fatigue and Oxygen Debt
• When a muscle is fatigued, it is unable to contract
• The common reason for muscle fatigue is
Oxygen must be "repaid" to tissue to remove oxygen debt
Oxygen is required to get rid of accumulated
• Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less
Muscle Tone
• Some fibers are contracted even in a relaxed muscle
• Different fibers contract at different times to provide muscle tone
• The process of stimulating various fibers is under involuntary control
Muscles and Body Movements
• Movement is attained due to a muscle moving an attached bone
• Muscles are attached to at least two points
o
- attachment to a moveable bone
- attachment to an immovable bone
Five Golden Rules of Gross Muscle Activity
1. All muscles cross at least
joint
2. The bulk of muscles lies
to the joint crossed
3. All muscles have at least
attachments: origin & insertion
4. Muscles only
/never
5. During contraction, the muscle insertion moves toward the origin
Effects of Exercise on Muscle
•
result in stronger muscles due to increase blood supply
Muscle fibers increase mitochondria and oxygen storage
Muscle becomes more fatigue resistant
Heart enlarges to pump more blood to body
Does not increase skeletal muscle size
•
results in the increase of muscle size & strength
o Individual muscle cells make more contractile filaments & connective tissue increases
Types of Ordinary Body Movements
• Flexion, Extension, Rotation, Abduction, & Circumduction
Types of Muscles
o
o
o
o
•
- muscle with the major responsibility for a certain movement
•
- muscle that opposes or reverses a prime mover
•
- muscle that aids a prime mover in a movement and helps prevent rotation
•
- stabilizes the origin of a prime mover
Muscles Diseases and Disorders
• Muscular Dystrophy
o Congenital muscle-destroying disease affect specific muscle groups
o Muscle fibers degenerate & atrophy due to an absence of dystrophin, a protein that helps keep muscle cells intact
o Most common & serious—Duchenne's M.D.
o Mostly in males (diagnosed between 2-6 yrs)
o Survival is rare beyond early 30's
o X-linked recessive
• Myasthenia gravis
o Rare adult disease caused by antibodies to acetylcholine receptors at the neuromuscular junction which prevents the muscle
contraction from occurring
o Drooping upper eyelids, difficulty swallowing & talking, muscle weakness & fatigue
o Death occurs when respiratory muscles cease to function