1. Notes: Skeletal Muscle Anatomy

2. (1) Levels of Organization
Muscle (whole organ)
Fascicle (portion of muscle)
Muscle Fiber (single muscle cell)
Myofibril (muscle cell organelle)
Sarcomere (portion of myofibril)
Myofilament (part of sarcomere)
Macroscopic
Microscopic

3. Thick Filament (myosin)
Fascicle
Muscle (organ)
Muscle Fiber (cell)
Myofibril
Muscle Fiber
(with many nuclei)
Sarcomere
Thin Filament (actin)
Thick Filament (myosin)

4. (2) Muscle Organ of muscular system Contains: Covered By: Muscle Cells
Connective Tissue
Blood Vessels & Nerves
Contractile Units
Covered By:
Epimysium (outer tissue-membrane)

6. (3) Fascicle Portion of muscle-organ One step down from whole muscle
Relationships:
Bunch of Fascicles = Muscle
Fascicle = Bunch of Muscle Fibers

8. (4) Muscle Fiber Actual Muscle Cell Contains: Relationships:
Multiple nuclei
Striations
Complex organelles called myofibrils
Relationships:
Bunch of Muscle Fibers = Fascicle
Muscle Fiber = Bunch of Myofibrils & Nuclei

11. (5) Myofibril Organelle in a muscle cell Contains: Relationships:
Contractile Units (Sarcomere)
Relationships:
Bunch of Myofibrils = Muscle Fiber
Myofibril = Bunch of Sarcomere

13. (6) Sarcomere Portion of myofibril Contains: Relationships:
Contractile proteins
Thin filaments with actin
Thick filaments with myosin
Relationships:
Bunch of Sarcomeres = Myofibril
Sarcomere = Bunch of Myofilaments (Actin + Myosin)

15. (7) Myofilaments Contractile portions of sarcomere Types:
Thin filaments w/actin (type of protein)
Thick filaments w/myosin (type of protein)
Relationships:
Bunch of Myofilaments = Sarcomere
Myofilaments = DO THE CONTRACTIONS