Muscles and movement

Function of a muscle: provides the force required for movement by moving one bone(point of insertion) in relationto another (point of origin) 

Types of muscle: 

• cardiac muscle: myogenic, eg: the heart
• smooth muscle: involuntary, eg: blood vessels and gut
• skeletal(straited/striped): voluntary, eg: limbs

Each muscle fibre has the following specialised features designed to facilitate muscular contraction

• Many nuclei fibres are long and were formed from many muscle cells fusing together, hence the fibres are multinucleated) 
• large number of mitochindria (muscle contraction requires a lot of ATP) 
• tubular myofibrils, divided into sections called sarcomeres and made of 2 different myofilaments (proteins required for contraction). Where thin(sctin) and thick ( myosin) filaments overlap a dark band occur, and this is flanked by light regions containing thin filament only
• The membrane surrounding a muscle fibre is called the sarcolemma
• The internal membranous network is called the sarcoplasmic reticulum, it is analogous to…