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Which of the following is the name of a division within the Ponce Health Sciences University School of Medicine?
Which of the following is the name of a division within the Ponce Health Sciences University School of Medicine?
What is the name of the textbook mentioned in the content?
What is the name of the textbook mentioned in the content?
Who is the author of the content provided?
Who is the author of the content provided?
What is the main subject matter of the content?
What is the main subject matter of the content?
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What is likely the intended audience for this content?
What is likely the intended audience for this content?
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What is the function of the epimysium?
What is the function of the epimysium?
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Which of the following is NOT a component of a sarcomere?
Which of the following is NOT a component of a sarcomere?
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What is the function of the T-system in skeletal muscle?
What is the function of the T-system in skeletal muscle?
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What is the function of the sarcoplasmic reticulum in skeletal muscle?
What is the function of the sarcoplasmic reticulum in skeletal muscle?
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What is the function of the neuromuscular junction?
What is the function of the neuromuscular junction?
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Which of the following is a characteristic of cardiac muscle?
Which of the following is a characteristic of cardiac muscle?
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Which of the following is a characteristic of smooth muscle?
Which of the following is a characteristic of smooth muscle?
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Which of the following is NOT a characteristic of skeletal muscle?
Which of the following is NOT a characteristic of skeletal muscle?
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What is the function of the spindle muscle?
What is the function of the spindle muscle?
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Study Notes
Muscle Tissue Overview
- Muscle tissue is composed of elongated cells called muscle fibers (muscle cells).
- Its function is to move structures and produce contractions.
- Terminology:
- Fiber: muscle cell
- Myo: muscle
- Sarco: muscle
Striated Muscle
- This category includes skeletal and cardiac muscle.
Skeletal Muscle
- Attached to at least one end of the skeleton.
- Composed of bundles of long, cylindrical, multinucleated cells (nuclei are peripheral).
- Exhibits cross-striations.
- Generates strong contractions of short duration.
- Contractions are typically under voluntary control (somatic innervation).
- Cells range up to 100µm in diameter.
Cardiac Muscle
- Constitutes most of the heart (and some walls of pulmonary veins and superior vena cava).
- Exhibits both cross-striations and intercalated discs (sites of contact between individual cardiac muscle cells).
- The cells are smaller than skeletal muscle cells (10-20µm in diameter), branched, and possess one or two nuclei located centrally.
- Produces rhythmic, strong, and continuous contractions under involuntary control (autonomic innervation).
Non-Striated Muscle
- This includes smooth muscle.
Smooth Muscle
- Composed of fusiform cells without striations.
- Arranged in sheets, forming layers in walls of tubes and hollow structures.
- Chief role involves regulating the size of lumina or cavities.
- Produces weaker contractions that can last longer.
- Contraction is involuntary (autonomic innervation).
Skeletal Muscle Organization
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Epimysium: Connective tissue surrounding the entire muscle.
- Continuous with the tendon.
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Perimysium: Connective tissue surrounding fascicles (bundles of muscle fibers).
- Contains larger blood vessels and nerves.
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Endomysium: Connective tissue surrounding individual muscle fibers.
- Contains capillaries and nerve endings.
- Similar to a basal lamina.
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Function: Transmits the pull of muscle cells to the bone (CAMs).
Organization of the Muscle
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Muscle → Fascicles → Fibers → Myofibril → Myofilaments (actin & myosin)
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The muscle fibers exhibit cross-banding (sarcomere, Z line, I band, A band, H band, M lines, desmin).
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The T-system (transverse tubules, triads, sarcoplasmic reticulum [SR]) is crucial in muscle contraction.
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Contraction control is coordinated by:
- Motor nerve: neuromuscular junction & motor end plate
- Sensory nerve: neuromuscular spindle
Cardiac Muscle Organization
- Contains a specialized system called the T-tubule-sarcoplasmic reticulum (SR) junction (called the triad). In the heart, it is called a diad.
- Contains a terminal cistern for storage of calcium.
- Muscle fiber organization also includes specialized intercalated discs crucial for electrical connections between cells.
Smooth Muscle Organization
- Smooth muscle cells have a different structure and specialized proteins compared to other muscle types.
- The primary features of smooth muscle are focal densities, and adhesion densities that hold the cells together during contraction.
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Description
Explore the intricacies of muscle tissue, including the different types such as skeletal and cardiac muscle. This quiz covers muscle fiber structures, functions, and key terminology. Test your understanding of how muscle tissues contribute to movement and contractions.
