MUSCLE TISSUE NOTES

Types of Muscle Tissue

• Three main types of muscle tissue in the human body:

  • Skeletal Muscle

  • Cardiac Muscle

  • Smooth Muscle

Functions of Muscle Tissue

• Generate Muscle Tension

  • Muscle tension is responsible for pulling or pushing movements.

  • Example: Lifting an arm involves muscle tension.

• Create Movement

  • Muscles are essential for any movement of the body, including hands and limbs.

• Maintain Posture

  • Involves the use of muscles for sitting, standing, and overall body alignment.

• Stabilize Joints

  • Muscles help stabilize joints in the body, contributing to overall movement and posture.

• Generate Heat

  • Muscle activity uses significant energy, and energy metabolism produces heat.

• Regulate Flow of Materials

  • Involvement of smooth muscles in organs, such as intestines, to move materials.

  • Skeletal muscles assist in venous returns, pushing blood toward the heart.

Skeletal vs. Cardiac Muscle

• Both skeletal and cardiac muscles are striated, characterized by stripes (striations).

• Skeletal Muscle

  • Composed of long fibers (muscle cells).

  • Each fiber is multinucleated (multiple nuclei).

  • Under conscious control (voluntary).

• Cardiac Muscle

  • Found exclusively in the heart.

  • Cells are shorter and can be branched.

  • Usually have one or two nuclei per cell.

  • Contains intercalated discs, important for heart function.

  • Involuntary control (cannot consciously control heartbeat).

Smooth Muscle

• Lacks striations, appearing smooth.

• Cells are flat and spindle-shaped with tapering ends.

• Contains a single centrally located nucleus.

• Found in walls of hollow organs (e.g., intestines) and other areas like the eyes and skin.

• Involuntary control (not consciously controlled).

Properties of Muscle Cells

• Contractility

  • Ability to contract due to the interactions of protein filaments within cells.

• Excitability

  • Responsive to stimuli or external signals.

• Conductivity

  • Ability to conduct electrical impulses along the plasma membrane.

• Distensibility

  • Ability to stretch without damage.

• Elasticity

  • Ability to return to original length after being stretched.