anat_unit 4_skeletal muscle anatomy notes

7/23/2019 ANAT_unit 4_skeletal Muscle Anatomy Notes

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Notes: Skeletal Muscle Anatomy



(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



Muscle (organ)Fascicle

Muscle Fier (cell)

Muscle Fier

(!it" many nuclei)

Myofiril

Sarcomere

#"in Filament (actin)

#"ick Filament (myosin)



($) Muscle

• Organ of muscular system

• Contains:

– Muscle Cells – Connective Tissue

– Blood Vessels !erves

– Contractile "nits

• Covered By:

– #$imysium (outer tissue%membrane)



(%) Fascicle

• &ortion of muscle%organ

• One ste$ do'n from 'ole muscle

• Relationships:

– Bunc of Fascicles Muscle

– Fascicle Bunc of Muscle Fibers



(&) Muscle Fier

• *ctual Muscle Cell

• Contains:

– Multi$le nuclei

– Striations

– Com$le+ organelles called myofibrils

• Relationships:

– Bunc of Muscle Fibers Fascicle

– Muscle Fiber Bunc of Myofibrils !uclei



(') Myofiril

• Organelle in a muscle cell

• Contains: – Contractile "nits (Sarcomere)

• Relationships: – Bunc of Myofibrils Muscle Fiber

– Myofibril Bunc of Sarcomere



() Sarcomere

• &ortion of myofibril

• Contains:

– Contractile $roteins

– Tin filaments 'it actin

– Tic, filaments 'it myosin

• Relationships:

– Bunc of Sarcomeres Myofibril

– Sarcomere Bunc of Myofilaments (*ctin - Myosin)



() Myofilaments

• Contractile $ortions of sarcomere

• Types: – Tin filaments '.actin (type of protein)

– Tic, filaments '.myosin (type of protein)

• Relationships:

– Bunc of Myofilaments Sarcomere

– Myofilaments /O T0# CO!T1*CT2O!S

anat_unit 4_skeletal muscle anatomy notes

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