what are the functions of the muscular system?

Produces movement, maintains posture, stabilizes joints, generates heat.

the ability to respond to a stimulus

Excitability

The ability to shorten when stimulated

Contractability

the ability to lengthen or stretch, even past their original shape

Extensibility

the ability to recoil or bounce back to the original shape and length after being stretched

Elasticity

connects to bones

Cylindrical
• Striated (muscle
fibers have stripes)
• Multinucleated
• Voluntarily
controlled
• Contracts slowly or
very quickly

skeletal muscle

Found in heart
• Branched
• Striated
• Uninucleated
• Involuntarily
controlled
• Mostly slow and
steady contractions except during short periods of activity

Cardiac Muscle

Found in walls of internal organs (ex: stomach)
• Arranged in uniform layers
• Nonstriated
• Uninucleated
• Involuntarily
controlled
• Slow contractions,
sustained for long periods of time

smooth muscle

Skeletal muscle is attached to bone by tendons

-Made of many bundles of fibers

Muscle

Bundles within muscles

Fascicle

Long, thin muscle cells

-Each is covered by sarcoplasmic reticulum, which transmit an impulse to the muscle fiber

Muscle Fiber

-Thread-like organelles of the muscle fibers

-Structured in long, striated units called sarcomeres

MyoFibril

2 types of filaments: actin (thin) & myosin (thick) make up the sliding filament model of the muscle

-Responsible for contracting activity of muscle fibers

Myofilaments

the membrane that covers the whole muscle

Epimysium

membrane that covers a fascicle

Perimysium

membrane that covers an individual muscle fiber

Endomysium

space between two Z-lines

sarcomere

____ and ____ filaments work together to produce a muscle contraction.

Actin; Myosin

• Nerve impulses are sent to the muscle fibers to begin contraction.
• Myosin filaments have rounded extensions called heads. These heads attach to the twisted actin filaments and pull on them. The Z-lines get closer together, and the sarcomere gets shorter.

sliding filament theory

energy required for the sliding filament theory

ATP

ATP is formed through ___ ____.

Cellular respiration

Cellular respiration depends on the presence of ______.

oxygen

Step one of muscle fatigue

muscles are worked strenuously and the glucose supply is exhausted.

Intense Exercise

Step two of muscle fatigue

ATP is no longer efficiently being used for cross-bridges

Muscle Fatigue

Step three of muscle fatigue:

Muscles begin to burn, causing you to stop exercising before cells are injured

Anaerobic Respiration

Step four of muscle fatigue

A difference occurs between the amount of oxygen available and the amount required and you are “out of breath”

Oxygen Debt

Muscles are attached to bones by ____.

tendons

The attachment of the tendon to the more stationary bone is called the _____.

origin

The attachment to the more movable bone is called the ______.

insertion

the middle of the muscle

belly

muscle doing the action

prime mover

muscles that help in that same direction

synergists

opposing muscle relaxing during motion

Antagonist