Anatomy Muscle System

Muscular System Review Sheet

1. What are the 4 main functions of the muscular system?

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

2. What are the 4 characteristics of muscle tissue and explain what they are?

  • Excitability- ability to respond to a stimulus

  • Contractability- ability to shorten when stimulated

  • Extensibility- ability to lengthen/stretch past original shape

  • Elasticity- ability to recoil or bounce back to original shape after stretching.

3. What are the 5 components we discussed of the microscopic structure of a

skeletal muscle in order?

  • Muscle → fascicle → muscle fiber → myofibril →myofilaments

4. Define epimysium, perimysium, and endomysium.

  • Epimysium- covers the whole muscle

  • Perimysium- covers a fascicle

  • Endomysium- covers an individual muscle fiber

5. What is a sarcomere?

  • Sarcomere- the space between two Z-Lines (place where actin and myosin filaments attach)

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

  • ATP

7. What is the role of ATP in muscle contraction?

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

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

  • Krebs Cycle→34 ATP

  • Fermentation→2 ATP

9. Is oxygen available or unavailable for both the Krebs Cycle and Fermentation?

  • Krebs Cycle→Oxygen is available

  • Fermentation→Oxygen is unavailable

10.What are some ways muscles can become fatigued? Explain them.

  • Intense Exercise→muscles are worked strenuously and the glucose supply is exhausted.

  • Muscle Fatigue→ATP is no longer efficiently being used for cross-bridges

  • Anaerobic Respiration→Muscles begin to burn, causing you to stop exercising before cells are injured

  • Oxygen Debt→A difference occurs between the amount of oxygen available and the amount required

  1. How do muscles attach to the skeleton?

  • Muscles attach to the skeleton through tendons. 

12.Where does a muscle originate? Insert?

  • The origin of a muscle is where the tendon is attached to the stationary part of the bone, the insertion is attached to the more movable bone. 

13.Why does muscular dystrophy happen?

  • Muscular dystrophy is due to genetics, or a problem with the way the body makes the proteins, causing the muscles to not work properly.

14.What are the early signs of muscular dystrophy? Late progressive signs?

  • Early signs→weakness in muscles