DIFFERENCES BETWEEN SINGLE-UNIT AND MULTI-UNIT SMOOTH MUSCLES
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Single-unit Smooth Muscles
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Multi-unit Smooth Muscles
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1.
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They are composed of muscle fibres closely
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1.
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They are composed of muscle fibres not so
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joined together.
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closely joined together.
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2.
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All the fibres of single smooth muscle
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2.
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All the fibres of a multiunit muscle contract
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contract together as a single unit.
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as separate units.
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3.
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Muscles of the wall of hollow visceral organs
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3.
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Muscles of the wall of large blood vessels,
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(e.g., Gastrointestinal tract and urinary
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arrector pili muscles of skin dermis, ciliar and
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bladder) are examples of this type of muscles.
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iris muscles in the eyes are examples of this
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type of muscles.
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