muscular system

• Three types of muscles

  • Cardiac muscle
  • Skeletal muscle
  • Smooth muscle
• Muscle cell

  Muscle fibre
• Skeletal muscle

  • Most attached to bones by tendons
  • Multinucleated
  • Striated
  • Voluntary (somatic nervous system)
• Skeletal muscle function

  1. Action potential transmitted from neuron at neuromuscular junction

  2. Sliding filament theory involving actin and myosin

  3. Requires calcium and ATP
• Sarcomere

  The functional contracting unit of a muscle
• Transmission of action potential from neuron to muscle

  1. Perimysium

  2. Epimysium

  3. Fascicle

  4. Endomysium
• Skeletal muscle functions

  • Movement
  • Maintaining posture
  • Stabilising joints
  • Generates heat
• Smooth muscle

  • Lacks striations
  • Spindle-shaped cells
  • Single nucleus
  • Involuntary—no conscious control
  • Found mainly in the walls of hollow organs e.g. stomach, arteries
• Cardiomyocytes

  • Striations
  • Usually has a single nucleus
  • Branching cells
  • Joined to another muscle cell at an intercalated disc
  • Involuntary
  • Found only in the heart
• Skeletal muscles

  • Most cross at least one joint
  • Have at least two attachments
  • Can only pull, never push

  
• Effect of exercise on muscle

  Increases muscle size, strength and endurance
• Types of exercise

  • Aerobic (endurance & strength)
  • Resistance (size & strength)
• Ways of naming muscles

  • Location e.g. temporalis
  • Number of origins e.g. triceps, biceps
  • Direction of muscle fibres e.g. rectus (straight)
  • Relative size e.g. maximus, medius, minimus
  • Location of muscle attachments e.g. sterno
  • Shape of muscle e.g. deltoid
  • Action of the muscle e.g. flexors, extensors
• Head and neck muscles

  • Facial muscles
  • Muscles of quiet respiration
• Facial muscles

  • Expressions
  • Mastication
  • Tongue movement (for speech)
  • Swallowing
  • Movement of eyeball
• Muscles of quiet respiration

  • Inspiration: Diaphragm, External intercostal
  • Expiration: none
• Torso, shoulder, arm (anterior)

  • pectoralis
  • deltoid
  • biceps brachii

  
• Torso, shoulder, arm (posterior)

  • latissimus dorsi
  • triceps brachii
  • trapezius
  • deltoid
  • sternocleidomastoid

  
• Muscles of the pelvis, hip, thigh (posterior)

  • Gluteus medius
  • Gluteus maximus
  • Hamstrings (Semitendinosus, Biceps femoris, Semimembranosus)
  • gastrocnemius
• Quadriceps femoris (group)

  • Rectus femoris
  • Vastus lateralis
  • Vastus intermedius
  • Vastus medialis
• Muscles of the lower leg

  • gastrocnemius
  • soleus
  • calcaneal (Achille's) tendon

  
• 3 body planes 


  coronal- separates front and back of the body

  sagittal- separates left and right sides of the body

  transverse- separates the upper and lower parts of the body