Anatomy of Skeletal Muscles

Skeletal Muscles

• Also known as striated muscles
• Voluntary muscles, meaning they can be controlled consciously
• Attached to bones and help move the body's skeleton
• Responsible for movement, posture, and balance
• Examples:
  • Biceps and triceps in the arm
  • Quadriceps and hamstrings in the leg
  • Pectoralis major in the chest

Muscle Anatomy

• Muscle Fiber: The basic structural unit of a muscle
  • Composed of:
    • Myofibrils (containing actin and myosin filaments)
    • Sarcoplasm (cytoplasm of the muscle fiber)
    • Sarcoplasmic reticulum (smooth endoplasmic reticulum)
    • Mitochondria (for energy production)
• Muscle Belly: The main part of the muscle, where contraction occurs
• Tendons: Connective tissue that attaches muscles to bones
• Aponeurosis: A type of tendon that is flat and sheet-like, often found in muscles of the back and abdomen
• Muscle Origins: The point where a muscle attaches to a bone, usually a fixed point
• Muscle Insertions: The point where a muscle attaches to a bone, usually a movable point

Skeletal Muscles

• Also known as striated muscles, they are voluntary muscles that can be controlled consciously
• Attached to bones, they help move the body's skeleton and are responsible for movement, posture, and balance
• Found in the arm, leg, and chest, examples include biceps and triceps, quadriceps and hamstrings, and pectoralis major

Muscle Anatomy

• A muscle fiber is the basic structural unit of a muscle, composed of myofibrils, sarcoplasm, sarcoplasmic reticulum, and mitochondria
• Myofibrils contain actin and myosin filaments, which are essential for muscle contraction
• Sarcoplasm is the cytoplasm of the muscle fiber, while sarcoplasmic reticulum is a type of smooth endoplasmic reticulum
• Mitochondria are responsible for energy production in the muscle fiber
• The muscle belly is the main part of the muscle where contraction occurs
• Tendons are connective tissue that attaches muscles to bones, allowing for movement
• Aponeurosis is a type of tendon that is flat and sheet-like, often found in muscles of the back and abdomen
• Muscle origins are the points where a muscle attaches to a bone, usually a fixed point
• Muscle insertions are the points where a muscle attaches to a bone, usually a movable point

Skeletal Muscles

• Also known as striated muscles, attached to bones to facilitate body movement
• Voluntary muscles, controlled consciously

Muscle Composition

• Muscle tissue consists of muscle fibers, connective tissue, and nerve endings
• Muscle fibers contain myofibrils, which are contractile units
• Myofibrils contain myosin and actin filaments that slide past each other during contraction

Muscle Types

• Slow-twitch (red) muscles: for endurance, slow contraction, and high oxygen supply
• Fast-twitch (white) muscles: for speed and power, rapid contraction, and low oxygen supply

Muscle Functions

• Movement: muscle contraction and relaxation to move bones and joints
• Stabilization: maintaining posture and joint stability
• Support: maintaining muscle tone to support body position

Muscle Contraction Types

• Concentric contraction: muscle shortens during contraction (e.g., bicep curl)
• Eccentric contraction: muscle lengthens during contraction (e.g., lowering a weight)
• Isometric contraction: muscle contracts without moving the joint (e.g., wall sit)