Download The Sense of Smell Notes

Muscle Anatomy Book Notes - Chapter 7.2 – page 116+
Name __________key_______________ P. __ Date_______
Skeletal muscle tissue has alternating light and dark bands, giving it a striated appearance
I. Muscle Fiber
In a muscle cell (aka muscle fiber) the plasma membrane is called the sarcolemma the cytoplasm
is called the sarcoplasma and the endoplasmic reticulum is called the sarcoplasmic reticulum
T- tubules dip down into the muscle fiber. Ca+2 ions, which are needed for muscle contraction
are stored in the T-tubules.
Muscle fibers are made of myofibrils.
A. A sarcomere is a portion of a myofibrils (from one Z line to another)
B. Myofibrils are made of 2 types of protein myofilament The thick filament is made of
the protein myosin and the thin filament is made of the protein actin
C. The darker region of the A band in the sarcomere is produced by overlapping actin and
myosin filaments.
D. The thick filaments are made of myosin molecules which are shaped like a golf club
E. The thin filaments are made of 2 intertwining strands of actin molecules.
F. A muscle contracts when the actin filaments begin to slide toward each other.
G. ATP provides the energy for muscle contraction.
Sj08