The Muscular System HLTAP301A

The Muscular System This topic examines different muscle types and how skeletal muscles contract and thus enable body movement

Types and Functions Skeletal Attached to bone Voluntary Appears striated Produce movement Maintain body posture stabilise joints Produce heat - homeostasis

Types and Function Smooth Found in walls of organs like the stomach and bladder Found in tubes and passageways such as the bronchioles and blood vessels Involuntary Non-striated

Types and Function Cardiac Found only in the heart Striated Cells fit tightly together to allow for rapid transmission of electrical impulses involuntary

Muscle contraction Two parts to this process Excitation – the ability to receive and respond to stimulus Contraction – the ability to shorten when stimulated

Muscle Tone Normal, continuous state of partial muscle contraction Helps maintain blood pressure in blood vessels Ready for action Flaccid is the term for muscle without proper muscle tone

Naming Skeletal Muscles Based on size, shape, orientation of fibres, location, muscle action Size – maximus,longus, minimus and brevis Shape – deltoid, trapezius Direction of fibres – rectus, oblique, transverse Location – gluteus, sub, lateralis Number of origins – biceps, triceps, quadriceps

Disorders Atrophy – wasting of muscle tissue Cramp – painful, involuntary skeletal muscle contraction Hypertonia – increased muscle tone causing rigidity Myalgia – pain or tenderness in muscles Myopathy – disease of the muscles not associated with nervous system