The Muscular System

FUNCTIONS

• Movement
• Bodily functions
• Circulation – metabolic pump
• Posture
• Heat control

TYPE AND STRUCTURE

Voluntary muscle = Skeletal muscle 

• Under conscious control
• Responsible for voluntary movements
• Striped appearance
• Long fibres interspersed with connective tissue
• Good blood and nerve supply 

Involuntary muscle = Smooth muscle 

• Not under conscious control
• Responsible for bodily functions
• Smooth not striped appearance
• Small spindle-shaped cells up 0.5 mm long 

Cardiac muscle

• Not under conscious control
• Responsible for heartbeat
• Microscopically striated
• Own nerve supply and affected by hormones 

NERVE SUPPLY

Muscles work because of stimulation by nervous system 

CHARACTERISTICS

• Excitability
• Contractability
• Extensibility
• Elasticity

MUSCLE CONTRACTION

• Muscle works by shortening
• Each individual muscle fibre contracts fully
• Fibres slide over each other to make muscle length shorter

ORIGIN AND INSERTION

• Origin is where the muscle starts
• Insertion is where the muscle ends
• Muscle usually works by moving insertion towards origin 

MUSCLE ACTIONS

• Muscles work by pulling not pushing
• So when one muscle shortens / contracts another must lengthen / relax
• Muscles therefore work in pairs
• When the prime mover / agonist contracts the antagonist relaxes
• Muscles which stabilise joints are known as synergists
• Sphincters are muscles surrounding orifices

ENERGY / WASTE PRODUCTS

• Energy for muscle work comes from oxygen, glycogen and fat
• Of energy used 30% produces work and 70% produces heat and waste products
• Waste products are carbon dioxide, lactic acid, heat and water

MUSCLE TONE

• Muscles are always in state of slight contraction called muscle tone
• Function of muscle tone
  • Maintain posture
  • Works metabolic pump
  • Keeps body in state of readiness 

MUSCLE FATIGUE

Continuous stimulation of muscle leads to weakening contractions when muscle no longer responds

MUSCLE TENSION

Increase in normal muscle tone 

MUSCLE SORENESS

Waste products build up until fibres can no longer slide over each other

EFFECTS OF MASSAGE ON MUSCULAR SYSTEM

• Increased removal of waste products
• Increased circulation of blood and lymph
• Increase in peripheral blood flow
• Muscle relaxation
• Increase muscle tone
• Breakdown / Prevention of adhesions 

Anatomy and Physiology On-line training
Gill Tree Training

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