Week 3 & 4

• Perimysium


  Connective tissue layer which surrounds the bundles of muscle fibres
• Endomysium


  Connective tissue layer which surrounds each muscle fibre
• Epimysium


  Connective tissue layer which surrounds the whole muscle
• Types of muscle tissue

  • Cardiac
  • Smooth
  • Skeletal
• Cardiac muscle


  Found in the heart walls
• Smooth muscle


  Found in the intestines and internal organs (visceral organs)
• Skeletal muscle


  Found in the general muscles around the body
• Muscle naming


  Named for the origin/insertion/location/action
• Origin


  Muscle attached to the less movable bone
• Insertion


  Muscle attached to the more movable bone
• Agonists (prime movers)


  Muscles that perform the primary movement
• Antagonists


  Muscles that perform the opposite movement to the prime movers
• Synergists


  Muscles that perform the same movement as the prime mover and stabilize the movement
• Reciprocal Inhibition


  Mechanism where agonists and antagonists contract and relax in opposition
• Fixators


  Synergists that contract together to stabilise a joint (e.g. running, quads + hams and tibialis anterior + gastrocnemius)
• Actions of muscles at joints

  • Flexion
  • Extension
  • Hyperextension
  • Abduction
  • Adduction
  • Plantarflexion
  • Dorsiflexion
  • Pronation
  • Supination
• 2 facial muscles have fascicles in a sphincter arrangement
• Facial muscles act synergistically to create a smile
• 7 key muscles have a role in mastication and facial expression
• The temporalis and masseter muscles elevate the mandible
• Sternocleidomastoid is the prime mover for flexion of the head at the atlantooccipital joint
• Splenius muscles act as antagonists to sternocleidomastoid in head flexion, but are prime movers for head extension
• Muscles that promote facial expression lie in the scalp and the face and are unusual as they insert into the skin rather than onto bone
• Zygomatic major + minor


  Muscles that contract to create a smile
• Orbicularis oculi


  Muscle that contracts to create a blink
• Orbicularis oris


  Muscle that contracts to create a kiss
• Duchenne smile


  Zygomaticus and orbicularis oculi contract
• Non-Duchenne smile


  No zygomaticus and orbicularis oculi contraction
• The Buccinator sits posteriorly to the risorius
• Sternocleidomastoid is the prime mover of the head during flexion
• When the two components of the sternocleidomastoid muscle contract together = bilateral contraction
• Scalene muscles attach to the transverse process of vertebrae (anterior, middle, posterior) and attach to either the atlas or the axis (assist in breathing demand in exercise)
• Anterior muscles from the hip superiorly

  Flexors
• Anterior muscles from the hip inferiorly

  Extensors
• Abdominal muscles attach to each other along the midline by a broad aponeurosis which forms the linea alba, meaning 'white line', a tendinous seam that runs from the sternum to the pubic symphysis
• The abdominal muscles are really stretchy allowing for a big belly when needed, e.g. when pregnant and people with a pot belly
• Erector Spinae


  Three columns of muscles; prime movers of the trunk extension
• Medial Erector Spinae


  Contain the spinalis that run along spinous processes of vertebrae (upper lumbar and lower thoracic)
• Intermediate Erector Spinae


  Longissimus are really long and thick connecting to the transverse process of vertebrae
• Lateral Erector Spinae


  Iliocostalis are most lateral; arise from the iliac crest and ribs; insert onto transverse process of cervical vertebrae and superior ribs