The muscular system

• The muscular system

functionS

• Supports the skeleton
• Aids in movement
• Controls vital processes (breathing, heartbeat

3 Different Muscle Types:

• (1) Skeletal Muscle
• Attaches to and moves bones
• Striated (striped) – alternating light and dark bands
• Multiple nuclei in each cell
• Under brain’s conscious control
• Example: biceps, triceps

(2) Smooth muscle

• (2) Smooth muscle
• Spindle-shaped cells
• One nucleus per cell
• No striations
• Controls breathing, digestion

(3) Cardiac muscle

• (3) Cardiac muscle
• Striated
• Cells smaller than striated muscle
• 1 or 2 nuclei per cell
• Branching fibers
• Found only in the heart
• Never gets tired

Muscle functionS

• Voluntary muscle
• Contracts (moves) only when you want it to
• Moves bones of the skeleton
• Examples: biceps, triceps, abdominals
• Involuntary muscle
• Contracts (moves) on its own
• Involuntary movements
• Examples: cardiac, stomach, intestinal wall

What connects our bones and our muscles???

• Tendons
• Connect skeletal muscle to bone
• Ex. Achilles Tendon – connects gastrocnemius (calf) to heel bone
• Ligaments
• Connect bone to bone
• Ex. ACL – Anterior Cruciate Ligament
• connects femur to fibula
• “Little brown bear; three blind mice”

Malfunctions:

• Strain
• Damage to muscle or tendon due to heavy lifting, sports, or work
• Bleeding, bruising, pain
• Sprain
• Injury in joint
• Ligament stretched beyond capacity
• Torn ligaments require surgical repair

Malfunctions:

• Tendonitis
• Inflammation of tendon from overuse
• Common in limbs
• Aches, pain, stiffness
• Requires rest
• “Pulled hamstring”
• Strained hamstring muscle (back of thighs)
• Prevention: routine stretching to increase flexibility; exercise for balance, muscle tone

Knee Joint Animation

• http://kidshealth.org/misc/movie/bodybasics/bodybasics_knee.html