3 types of muscles
Smooth
Cardiac
Skeletal
Functions of muscle
Posture
Body Temp
Regular orifices
Support Soft tissues
Locomotion
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.
Sacromere
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)
ZHIAM
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...