Muscular System

• Types of Muscles


  • Skeletal
  • Cardiac
  • Smooth
• Skeletal muscle


  • Attached to bones
  • Striated
  • Voluntarily controlled
• Cardiac muscle


  • Located in the heart
  • Striated (not as skeletal muscles)
  • Involuntarily controlled
• Smooth muscle


  • Located in walls of blood vessels, hollow organs
  • Non-striated (tapered on ends, not as organized)
  • Involuntarily controlled
• Functions of Skeletal muscles

  • Movement
  • Maintain posture
  • Respiration
  • Production of body heat
  • Communication
• Function of Cardiac muscle

  Heart beat
• Function of Smooth muscle

  • Contraction of organs and vessels
  • Homeostasis for temperature
  • Digestive tract processes
• Properties of Muscles


  • Contractility
  • Excitability
  • Extensibility
  • Elasticity
• Skeletal muscle is 40% of body weight
• Skeletal muscle is called striated muscle
• Components of individual skeletal muscles

  • Muscle
  • Nerve
  • Connective tissue
• Origin


  Attachment at the least mobile location, stationary (not moving the bone as much)
• Insertion


  Attachment to the bone undergoing the greatest movement
• Belly


  The part of the muscle between the origin and the insertion
• Agonists


  A group of muscles working together to cause a movement
• Antagonists


  A muscle or group of muscles that oppose muscle actions
• Criteria for naming muscles

  • Location
  • Size
  • Shape
  • Orientation of fascicles
  • Origin and insertion
  • Number of heads
  • Function
• Facial Muscles


  • Temporalis
  • Masseter
  • Frontalis
  • Orbicularis Oris
  • Orbicularis Oculi
  • Buccinator
  • Zygomaticus major
  • Zygomaticus minor
• Sternocleidomastoid muscle


  • Both sides can contract together to pull head up and down
  • One side can contract at a time to turn head right and left
• Thoracic Muscles (Respiration)


  • External intercostals
  • Internal intercostals
• External intercostals


  Elevate ribs for inspiration (make them bigger)
• Internal intercostals


  Depress ribs during forced expiration (make them smaller)
• Diaphragm


  Moves up and down during quiet breathing
• Abdominal Wall Muscles


  • Rectus abdominis
  • External abdominal oblique
  • Internal abdominal oblique
  • Transverse abdominis
• Rectus abdominis


  Compresses abdomen
• External abdominal oblique


  Compresses abdomen
• Internal abdominal oblique


  Compresses abdomen
• Transverse abdominis


  Compresses abdomen
• Upper Scapular and Limb Muscles

  • Trapezius
  • Pectoralis major
  • Serratus anterior
  • Deltoid
• Trapezius


  Extends neck and head
• Serratus anterior


  Elevates ribs, brings scapula forward
• Upper Limb Muscles


  • Triceps brachii
  • Biceps brachii
  • Brachialis
  • Latissimus dorsi
• Triceps brachii


  Extends elbow
• Biceps brachii


  Flexes elbow and shoulder
• Brachialis


  Flexes elbow, helps as an agonist with the biceps brachii
• Latissimus dorsi


  Extends shoulder
• Forearm Muscles


  • Hand flexor group
  • Hand extensor group
• Muscles of Hips and Thighs

  • Iliopsoas
  • Gluteus maximus
• Iliopsoas


  Flexes hip
• Gluteus maximus


  Extends hip and abducts thigh