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MUSCLE TISSUE
Muscle Tissue
• If it contracts, it's muscle:
• Muscle tissue is categorized on the basis of a
functional property: the ability of its cells to
contract.
• consists of the contractile protein fibrils actin and
myosin. Muscle is responsible for movement of
the body and changes in the size and shape of
internal organs.
• Muscle cells are generally referred to as muscle
fibres.
• Muscle fibres are typically arranged in parallel
arrays allowing them to work together effectively
The three types of muscle:
Three types of muscle
tissue can be identified
histologically:
1. skeletal muscle (striated
muscle, voluntary),
2. cardiac muscle
3. smooth muscle (nonstriated muscle,
involuntary).
Skeletal muscle
• Skeletal muscle constitutes the muscle
that is attached to the skeleton and
controls motor movements and posture.
Skeletal Muscle
• Skeletal muscle fibres (cells) are
multinucleated
• They are filled with longitudinally arrayed
subunits called myofibrils.
• The myofibrils are made up of the myofilaments
myosin (thick filaments) and actin (thin
filaments).
• The striations reflect the arrangement of actin
and myosin filaments and support structures.
• The individual contractile units are
called sarcomeres.
Skeletal Muscle Summary
Summary: Skeletal muscle fibres bear
obvious striations, have many
peripherally located nuclei, are of the
same thickness throughout their length
and do not branch.
Skeletal Muscle
Skeletal Muscle
Cardiac Muscle
• Cardiac muscle is the type of muscle
found in the heart
• Cardiac muscle is intrinsically contractile
but is regulated by autonomic
(unconscious) and hormonal stimuli.
Cardiac Muscle Summary
• Striations are present (actin and myosin)
• Greater number of mitochondria present
• Cardiac muscle cells have only one or two
nuclei, which are centrally located.
• Cardiac muscle cells are joined to one
another in a linear array. The boundary
between two cells abutting one another is
called an intercalated disc.
• Cardiac muscle fibres are branched
Cardiac Muscle
Cardiac Muscle
Smooth Muscle
• Smooth muscle is the intrinsic muscle of
the internal organs, iris of the eye and
blood vessels.
• Like cardiac muscle, smooth muscle fibres
are intrinsically contractile but responsive
to autonomic and hormonal stimuli. They
are specialized for slow, prolonged
contraction.
Smooth Muscle
• Smooth muscle fibres are generally
arranged in bundles or sheets (no
striations)
• A single nucleus is located in the central
part of the fibre.
• Fibres do not branch.
• Smooth muscle fibres lie over one another
in a staggered fashion
• Fusiform Shape with tapered ends
Smooth Muscle
Musclel Tissue Summary
Muscle Tissue Summary