Muscle Fibers and Functions

Muscle Tissue Properties

• Excitability: Ability to respond to a stimulus, such as a nerve impulse
• Contractility: Ability to shorten and thicken
• Extensibility: Ability to stretch or lengthen
• Elasticity: Ability to return to original shape after being stretched or shortened

Muscle Function

• Movement: Muscles generate force to enable movement of the body and its parts.
• Posture: Maintain body position by providing continuous tension
• Heat production: Muscle contractions produce heat - important for maintaining body temperature
• Protection: Muscles help to protect internal organs

Muscle Motion

• Muscle contraction results in shortening the muscle fibers
• This shortening pulls on a bone, causing it to move
• Muscles work in pairs, with one muscle contracting and the other relaxing to create movement

Muscle Tension and Joint Positions

• When muscles generate tension in a joint position that is already at its maximum range of motion, it can lead to:
  • Strains: Overstretching or tearing of muscle fibers
  • Sprains: Damage to ligaments, which connect bones to each other

Muscle Excitability

• Irritability: the ability to respond to stimuli - is also known as excitability
• Stimuli come in different forms:
  • Nervous impulses
  • Hormones
  • Changes in temperature
  • Chemicals