Transcript Skeletal Muscle Review

The Muscular System
Muscle Control
Type of
muscle
Nervous
control
Type of
control
Example
Skeletal
Skeletal
Controlled
by CNS
Voluntary
Lifting a
glass
Cardiac
Regulated
by ANS
Involuntary Heart
beating
Smooth
Controlled
by ANS
Involuntary Peristalsis
Types of Responses
• Twitch– A single brief contraction
– Not a normal muscle function
• Tetanus
– One contraction immediately followed by
another
– Muscle never completely returns to a relaxed
state
– Effects are compounded
Where Does the Energy Come
From?
• Energy is stored in the muscles in the form
of ATP
• ATP comes from the breakdown of glucose
during Cellular Respiration
• This all happens in the Mitochondria of the
cell
• When a muscle is fatigued (tired) it is
unable to contract because of lack of
Oxygen
Muscle Contraction
1. The nerve impulse from motor neuron reaches synapse.
2. The impulse triggers the release of acetylcholine in the
synapse.
3. Acetylcholine binds to receptors on surface of muscle
cell, triggers an impulse.
4. Calcium ions in sarcoplasmic reticulum move toward
bind to troponin.
5. Troponin moves out, allowing actin and myosin to react.
6. The thin actin filaments slides inside the myosin
filaments, shortening. This is repeated for each
sarcomere, along the muscle fiber. This causes a
shortening of the entire muscle.
Muscle Relaxation
1. An enzyme present in the synaptic cleft,
acetylcholinesterase, destroys Ach shortly after it is
bound to the receptors. The membrane, thus, no
longer, responds to impulse.
2. Ca++ goes off troponin and is transported by into its
storage vesicles (using ATP). Actin and myosin are
no longer linked.
3. The sarcomere slides back into resting position.
The muscle relaxes.
Muscle Contractions
• Isotonic- muscles shorten/lengthen and
movement occurs (most normal exercise)
• Isometric- muscle is activated, but it is held
at a constant length
Injuries to the Muscles
• Just like our skeletal system, sometimes we may
injure our muscles.
Types of Injuries
• Contusions (muscle bruises)
– One of most common experienced by athletes
– Often caused by direct trauma/repeated blow
• Muscle Strains
– Occurs when muscle is overstretched or pulled
– Can be caused by sudden/forceful contraction of
muscle (lifting heavy weight)
• Tendonitis (inflammation of the tendon)
– Occurs when tendon is irritated and inflamed
– Can be caused by sudden pull on tendon and
overuse/repetitive movements
Muscle Strains
• Tears are often called
pulled or strained
muscles.
• The degree of the injury
will determine treatment
and recovery time.
Categories of Muscle Strains
• Grade I Strain: This is a mild strain and only some muscle
fibers have been damaged. Healing occurs within two to three
weeks.
• Grade II Strain: This is a moderate strain with more
extensive damage to muscle fibers, but the muscle is not
completely ruptured. Healing occurs within three to six weeks.
• Grade III Strain: This is a severe injury with a complete
rupture of a muscle. This typically requires a surgical repair of
the muscle; the healing period can be up to three months.
Body Building
• Many people work very
hard to build their muscles.
• They use various exercises
to build strength and muscle
mass.
• This is a common practice
with many men and women
today, and many compete in
contests.
How much is too much?
Types of Musculo-Skeletal Movement
Flexion
Extension
Hyperextension
Abduction, Adduction &
Circumduction
Rotation
More Types of Movement……
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Inversion- turn sole of foot medially
Eversion- turn sole of foot laterally
Pronation- palm facing down
Supination- palm facing up
Opposition- thumb touches tips of fingers
on the same hand