Summary Muscles

Muscles:
STRUCTURE FUNCTION
MUSCLE Contract in antagonistic pairs
(biceps = flexor & triceps =
extensor).
TENDON Connect muscle to bone and pull
on it when muscle contracts.
LIGAMENT Holds bones together to prevent
dislocation.
CARTILAGE Reduces friction/wear.
SYNOVIAL MEMBRANE Secretes synovial fluid.
SYNOVIAL FLUID Acts as a lubricant/ allows
smooth movement.


 Skeletal muscles are made up of thousands of muscle fibres.
 Muscle fibres are multinucleate because cells have fused
together to be longer to reduce the number of points of
weakness along a fibre.
 Each fibre is surrounded by a plasma membrane called a
sarcolemma, which has many deep folds called T-tubules.
 The cytoplasm is called sarcoplasm & it contains many
mitochondria (provide ATP) & specialised endoplasmic
reticulum called sarcoplasmic reticulum (which contains
calcium ions).
 They also contain myofibrils which
themselves are made up of two
types of myofilament – thin actin &
thick myosin.
 Myofibrils are the contractile units.
 To the left is a sarcomere – it
shortens in length as a muscle
contracts.