Muscular System

• Muscular System


  Responsible for the movement of the human body, comprised of muscles and tendons
• Types of muscle tissue

  • Skeletal Muscle
  • Cardiac Muscle
  • Smooth Muscle
• Skeletal Muscle


  • Voluntary, Controlled consciously, Striated (appears striped)
  • Function: Movement of bones and body parts, posture, heat production
• Cardiac Muscle


  • Involuntary, Controlled unconsciously, Striated (has a striped appearance)
  • Function: Pumps blood through the body
• Smooth Muscle


  • Involuntary, Controlled unconsciously, Non-striated (does not have a striped appearance)
  • Function: Moves substances through organs
• Muscle Fibers


  Long, cylindrical cells that make up muscles
• Myofibrils


  Protein structures that make up muscle fibers
• Sarcomeres


  The functional units of myofibrils, responsible for muscle contraction
• Sliding Filament Theory


  Describes how muscles contract by sliding actin (thin) filaments over myosin (thick) filaments
• Neuromuscular Junction


  The synapse between a motor neuron and muscle fiber where the nerve impulse triggers muscle contraction
• ATP


  Provides energy for muscle contractions
• Types of Muscle Contractions

  • Isotonic
  • Isometric
• Aerobic Respiration


  Produces energy with oxygen, used for long, sustained muscle activity
• Anaerobic Respiration


  Produces energy without oxygen, used for short bursts of activity
• Hypertrophy


  Increase in muscle size due to exercise
• Atrophy


  Decrease in muscle size due to lack of use
• Muscle Repair


  Muscle fibers repair themselves after injury through a process of inflammation, repair, and remodeling
• Muscular Dystrophy


  Group of genetic disorders causing muscle weakness and degeneration
• Myasthenia Gravis


  Autoimmune disorder affecting neuromuscular junctions, leading to muscle weakness
• Tendinitis

  Inflammation of tendons
• Muscle Fibers


  Long, cylindrical cells that make up skeletal muscles, contain multiple nuclei and are packed with myofibrils
• Myofibrils


  Rod-like units within muscle fibers, contain sarcomeres which facilitate contraction through the interaction of actin and myosin filaments
• Sarcomeres


  The smallest functional units within myofibrils, composed of actin (thin) and myosin (thick) filaments, responsible for muscle contraction through the sliding filament mechanism
• Tendons


  Tough, fibrous connective tissues that connect muscles to bones, transmitting the force generated by muscle contraction to move bones
• Fascia


  A layer of connective tissue that surrounds muscles, provides support and reduces friction between muscles during movement
• Skeletal Muscles

  • Voluntary, striated muscles attached to bones, enable voluntary movements, maintain body posture, generate heat
• Cardiac Muscle


  • Involuntary, striated muscle found only in the heart, contracts rhythmically and continuously to pump blood throughout the body, maintains circulation
• Smooth Muscles


  • Involuntary, non-striated muscles found in walls of hollow organs, move food through digestive tract, regulate blood flow and pressure, control airflow in lungs, aid in movement of urine
• Biceps Brachii


  Muscle located in the front of the upper arm, flexes the elbow and supinates the forearm
• Triceps Brachii


  Muscle located in the back of the upper arm, extends the elbow
• Deltoid


  Muscle located in the shoulder, abducts, flexes, and extends the arm at the shoulder joint
• Pectoralis Major


  Muscle located in the chest, adducts and medially rotates the arm
• Rectus Abdominis


  Muscle located in the front of the abdomen, flexes the spine and compresses the abdominal cavity
• Quadriceps Femoris


  Muscle located in the front of the thigh, extends the knee
• Hamstrings


  Muscles located in the back of the thigh, flex the knee and extend the hip
• Gastrocnemius


  Muscle located in the calf, plantar flexes the foot and flexes the knee
• Gluteus Maximus


  Muscle located in the buttocks, extends and laterally rotates the hip