Muscle Tissue Types and Characteristics

Muscle Tissue Types

• Three types of muscle tissue exist: skeletal, cardiac, and smooth.
• Skeletal muscle is voluntary, striated, and multinucleated.
• Cardiac muscle is involuntary, striated, and typically has one or two nuclei per cell.
• Smooth muscle is involuntary, non-striated, and has a single nucleus per cell.

Muscle Tissue Characteristics

Characteristics of muscle tissue

• Shape: Skeletal muscle is long and cylindrical, cardiac muscle is branched, and smooth muscle is spindle-shaped.
• Striations: Skeletal and cardiac muscle are striated (striped); smooth muscle is not.
• Nuclei: Skeletal muscle cells are multinucleated, cardiac muscle cells typically have one or two nuclei, and smooth muscle cells have a single nucleus.
• Control: Skeletal muscle is voluntary, cardiac muscle contracts rhythmically involuntarily, and smooth muscle contracts involuntarily.
• Examples: Skeletal muscle examples include biceps brachii and quadriceps; cardiac muscle is the heart muscle (myocardium); smooth muscle is found in blood vessel walls and intestines.

Skeletal Muscle Gross Structure

• Membranes:
  • Epimysium: A dense connective tissue encasing the entire muscle.
  • Perimysium: Connective tissue around fascicles (bundles of muscle fibers), containing nerves and blood vessels.
  • Endomysium: Thin connective tissue surrounding each individual muscle fiber.
• Fascicles: Bundles of muscle fibers within the skeletal muscle; their arrangement affects strength and range of motion.

Muscle Attachments and Related Structures

• Origin & Insertion:
  • Origin: The fixed attachment point of a muscle (usually proximal).
  • Insertion: The movable attachment point of a muscle (usually distal).
• Tendon/Aponeurosis:
  • Tendon: Connective tissue connecting muscle to bone.
  • Aponeurosis: A broad, flat tendon connecting muscles to structures.
• Bursa: Fluid-filled sac reducing friction between tissues (e.g., tendon and bone).
• Synovial Membrane: Lines joint cavities, producing synovial fluid for lubrication.
• Tendon Sheath: Protective covering around tendons, reducing friction.

Skeletal Muscle Functions

• Movement: Enables voluntary body movement.
• Posture Maintenance: Supports posture and stability.
• Heat Production: Generates heat during contractions, regulating body temperature.

Muscle Contraction and Bone Movement

• Muscle contraction shortens the muscle, pulling on tendons.
• This tension is transmitted to bones, causing movement at joints.
• Coordinated muscle contractions lead to smooth movements.
• Movement is determined by the origin and insertion points of the muscles, and the joints involved.

Test your knowledge on the three types of muscle tissue: skeletal, cardiac, and smooth. This quiz covers their characteristics, including shape, striations, control, and examples. Perfect for biology students looking to reinforce their understanding of human anatomy.