BIO110 Ch 38- The Musculoskeletal System

4 functions of the skeletal system

• Support

• Protection

• Movement and locomotion

• Stores calcium

Cells, protein fibers, matrix, and general structure of a long bone

• Cells: Osteoblasts, osteoclasts, osteocytes

• Protein fibers: Collagen

• Matrix: Collagen fibers

• General structure: Epiphysis, shaft

  • Compact bone- Outer dense layer (hard part)

  • Medullary bone- lines the internal cavity

  • Spongy bone- forms the epiphysis

4 types of joints

• Ball-and-socket joints

• Hinge joints

• Gliding joints

• Combination joints

Basic structure of a skeletal muscle cell

Composed of:

• Sarcolemma- special cell membrane

• Myofibrils

• Myofilaments- protein filaments

• Sarcoplasmic reticulum- type of ER surrounding each myofibril

• T-tubules- connect sarcolemma with sarcoplasmic reticulum

Sliding filament mechanism of muscle contraction

Thick and thin myofilaments slide past each other

How does a sarcomere work?

During contraction the sarcomere shortens, then relaxes during expansion

What is the role of calcium in muscle contraction?

Triggers interaction between actin and myosin filaments, which leads to contraction and relaxation

What are the sources of energy for muscle cell contraction?

ATP