Anatomy Muscle System

What are the 4 main functions of the muscular system?

Produce movement, maintain posture, stabilize joints, generate heat.

Excitability

The ability of muscle tissue to respond to a stimulus.

Contractability

The ability of muscle tissue to shorten when stimulated.

Extensibility

The ability of muscle tissue to lengthen/stretch past its original shape.

Elasticity

The ability of muscle tissue to recoil or bounce back to its original shape after stretching.

What are the 5 components of the microscopic structure of a skeletal muscle in order?

Muscle → fascicle → muscle fiber → myofibril → myofilaments.

Epimysium

Connective tissue that covers the whole muscle.

Perimysium

Connective tissue that covers a fascicle.

Endomysium

Connective tissue that covers an individual muscle fiber.

What is a sarcomere?

The space between two Z-Lines where actin and myosin filaments attach.

Where does the energy required for muscle fiber contraction come from?

ATP.

What is the role of ATP in muscle contraction?

It is required for energy to carry out contraction (sliding filament theory).

How much ATP is made from Krebs Cycle vs. Fermentation?

Krebs Cycle→34 ATP; Fermentation→2 ATP.

Is oxygen available in the Krebs Cycle and Fermentation?

Krebs Cycle→Oxygen is available; Fermentation→Oxygen is unavailable.

What are some ways muscles can become fatigued?

Intense exercise, muscle fatigue, anaerobic respiration, oxygen debt.

How do muscles attach to the skeleton?

Muscles attach to the skeleton through tendons.

Where does a muscle originate? Insert?

The origin is where the tendon is attached to the stationary part of the bone; the insertion is attached to the more movable bone.

Why does muscular dystrophy happen?

Due to genetics or a problem with the way the body makes proteins, causing muscles to not work properly.

What are the early signs of muscular dystrophy?

Weakness in muscles.