Skeletal Muscle Structure Flashcards
Also known as striated muscle
40% of body weight
Skeletal muscle
Skeletal muscle consists of ?
Skeletal muscle tissue
Nervous
Connective
Adipose
Each skeletal muscle is surrounded by a connective tissue called ?
Epimysium or muscular fascia
Each whole muscle is subdivided into numerous visible bundles called ?
Muscle fascicles
A loose connective tissue called the ________ separate muscle fascicles from each other
Perimysium
A loose connective tissue called the _________ surrounds each muscle fiber
Endomysium
The cell membrane of the muscle fiber is called ?
Sarcolemma
Sarcolemma has many tubelike inward folds called
Transverse tubes or T tubules
Occur at a regular intervals along the muscle fiber and extend into the center of the muscle fiber
T tubules
T tubules are associated with enlarged portions of the smooth endoplasmic reticulum
Sarcoplasmic reticulum
Cytoplasm of muscle fiber is called ?
Sarcoplasm
Within the sarcoplasm, each muscle fiber contains many bundles of
Protein filaments
These bundles are called ?
Myofibrils
Myofibrils consist of 2 major kinds of protein fibers
Actin myofilaments
Myosin myofilaments
Basic structural and functional unit of a skeletal muscle
Smallest portion of a skeletal muscle capable of contracting
Sarcomere
Separates one sarcomere from the next
Z disks
Is a network of protein fibers that forms a stationary anchor for actin myofilaments to attach
A Z disks
Light staining bands are called ?
Dark staining bands are called ?
I bands
A bands
Lighter staining region and contains only myosin myofilaments is called ?
H Zone
Consists of fine protein filaments that anchor the myosin filaments in place
M Line
Actin myofilaments or thin filaments are made of 3 components
Actin
Troponin
Tropomyosin
It has attachment sites for the myosin myofilaments
Resembles pearls twisted together
Actin strands
Have binding sites for Ca2+
Attached at specific intervals along the actin myofilaments
Troponin
Filaments block the myosin myofilaments binding sites
Tropomyosin