The Three Types of Muscles

The Three Types of Muscles

3 types of muscles


Functions of muscle

Body Temp
Regular orifices
Support Soft tissues

Muscle cell anatomy

Sarcolemma –cell membrane around muscle cell
Sarcoplasm – cytoplasm round muscle fiber
SR – release Ca for controlling contraction
Myofibrils – many myofilaments
Myoblast – creats skeletal muscle fibers
Myosatellite – repair and regenerate
Myofilament – contain actin (light and thin ) and myosin (dark and thick )
Inside Myofibrils – protein filament called sacromeres
T-tubules – muscle contractions
Triad – combo of T.C. and T.T.


Fuctional unit of S.muscle
Connected to make myofibrils
Each contracts to shorten the myofibril

BANDS of Sacromere

H( myosin only )
I (Actin only)
A (all of the Myosin)


Thin Filament – Actin, troponin, Tropomyosin

Blocks the active site on actin
Troponin holds tropomyosin in place
Ca binds to Troponin causing Troponin-tropomyson complex

Thick filament – myosin (globular head)

Tail attached to the Mline and head attaches to Ca if present
Cross-bridging when the Myosin heads cocks

Contraction of a muscle

Ca ions bind to troponin and moves tropomyosin out of the way to let the myosin bind to actin myofilament, ADP and Phos are attached to myosin head and then attach to actim myofilaments to form Cross bridge and realease Phos. Energy stored in the head of the myosin is used to move the head causes to actin to pass myosin and ADP is realease. The bond of actin and myosin is broken when ATP binds. ATP will be broken down to ADP and P in the myosin head and use in later movement ( if Ca is present)

Sliding Filament Theory

In the sliding filament model of muscle contraction, the (thin) actin myofilaments [red] (attached to the Z-line) slide (actually, are pulled) inward along the (thick) myosin myofilaments [blue], and the sarcomere (measured from one Z line to the next) is shortened. Note on the measuring...

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