lOMoARcPSD|44532475
Comprehensive Guide to Muscle, Bone, and Endocrine
Physiology
Fundamentals Of Human Anatomy And Physiology (University of North Carolina at
Chapel Hill)
Scan to open on Studocu
Studocu is not sponsored or endorsed by any college or university
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, lOMoARcPSD|44532475
Comprehensive Guide to Muscle, Bone,
and Endocrine Physiology
Muscle Tissue Structure and Function
Muscle tissue is specialized for contraction, enabling movement, posture,
and various bodily functions. It is composed of skeletal muscle fi bers
encased within connective tissues: the endomysium surrounds individual
fibers, the perimysium surrounds fascicles (bundles of fibers), and the
epimysium encases the entire muscle. These layers provide structural
support and pathways for blood vessels and nerves.
Within muscle fi bers, the fundamental contractile units are myo fi brils,
which are long, cylindrical structures composed of myo fi laments —
primarily actin (thin fi laments) and myosin (thick filaments). These
proteins are organized into repeating units called sarcomeres, the
functional units of muscle contraction. The arrangement of sarcomeres
gives skeletal muscle its striated appearance.
Sliding Filament Mechanism of Muscle
Contraction
Muscle contraction occurs through the sliding fi lament mechanism,
where actin fi laments slide past myosin fi laments, shortening the
sarcomere. During contraction:
The I band (containing only actin) and the H zone (central region of the
A band where only myosin is present) shorten.
The A band (length of the myosin fi laments) remains constant.
The Z discs (boundary of sarcomeres) move closer together.
The M line (center of the sarcomere) remains stationary.
Downloaded by madiba South Africa stuvia ()
Comprehensive Guide to Muscle, Bone, and Endocrine
Physiology
Fundamentals Of Human Anatomy And Physiology (University of North Carolina at
Chapel Hill)
Scan to open on Studocu
Studocu is not sponsored or endorsed by any college or university
Downloaded by madiba South Africa stuvia ()
, lOMoARcPSD|44532475
Comprehensive Guide to Muscle, Bone,
and Endocrine Physiology
Muscle Tissue Structure and Function
Muscle tissue is specialized for contraction, enabling movement, posture,
and various bodily functions. It is composed of skeletal muscle fi bers
encased within connective tissues: the endomysium surrounds individual
fibers, the perimysium surrounds fascicles (bundles of fibers), and the
epimysium encases the entire muscle. These layers provide structural
support and pathways for blood vessels and nerves.
Within muscle fi bers, the fundamental contractile units are myo fi brils,
which are long, cylindrical structures composed of myo fi laments —
primarily actin (thin fi laments) and myosin (thick filaments). These
proteins are organized into repeating units called sarcomeres, the
functional units of muscle contraction. The arrangement of sarcomeres
gives skeletal muscle its striated appearance.
Sliding Filament Mechanism of Muscle
Contraction
Muscle contraction occurs through the sliding fi lament mechanism,
where actin fi laments slide past myosin fi laments, shortening the
sarcomere. During contraction:
The I band (containing only actin) and the H zone (central region of the
A band where only myosin is present) shorten.
The A band (length of the myosin fi laments) remains constant.
The Z discs (boundary of sarcomeres) move closer together.
The M line (center of the sarcomere) remains stationary.
Downloaded by madiba South Africa stuvia ()
