How Do Muscles Work?
Ms. B’s 6th grade science class
By Beatriz Bofill
1Thursday, October 11, 12
Three Kinds of Muscle
Cardiac
Skeletal
Smooth
2Thursday, October 11, 12
Three Kinds of Muscle
Cardiac
Skeletal
Smooth
2Thursday, October 11, 12
Muscle Fibers
• A muscle is a bundle of many cells called fibers
diameter of a strand of hair diameter of a muscle fiber 100 microns ≈ 100 microns
typical cell ≈ 40 micronscannot be seen by the naked eye
3Thursday, October 11, 12
dark band light bandSarcomere
Myofibril and Sarcomere
Muscle Fiber
4Thursday, October 11, 12
Actin and Myosin Filaments
proteins sliding past each other
Sarcomere
Myofibril
Myocyte
Myofibrils
Filaments
5Thursday, October 11, 12
Actin and Myosin Filaments
proteins sliding past each other
Sarcomere
Myofibril
Myocyte
Myofibrils
Filaments
5Thursday, October 11, 12
Nerve Signaling Muscle Cell
Nerves
6Thursday, October 11, 12
Relaxed Muscle to Contracted Muscle
7Thursday, October 11, 12
Animation of a Muscle Contraction
8Thursday, October 11, 12
Vocabulary Words
myocytemyofibrilsarcomerefilamentactinmyosinmicron
9Thursday, October 11, 12