Skeletal muscle Flashcards
Functions of skeletal muscle
Movement
Posture
Stabilising joints
Generates heat
What is the myotendinous junction?
Area where collagen fibres of tendons are continuous with connective tissue of muscle
Define sarcolemma?
Plasma membrane
What is sarcoplasmic reticulum?
Smooth endoplasmic reticulus
Interconnecting tubules surround each myofibril
Terminal cisternae store calcium ions
What is the T tubule network?
Invaginations of sarcolemma deep into muscle fibre
Where are motor neuron cell bodies found
Spinal cord and brain
One muscle fibre=
One neuromuscular junction
Describe structure of muscle sarcolemma
Folded into ridges
Millions of Ach receptors
What is contained in axon terminal?
Synaptic vesicles
What happens when action potential reaches terminal?
Ach released into cleft and binds to receptors
Effect of activation of Ach receptors?
Causes action potential in sarcolemma
Travels down T tubules causing release of calcium ions from sacroplasmic reticulum into sarcoplasm
What is effect of calcium ion release?
Binds to troponin
Pulls tropomyosin away from myosn binding site on actin filament
Myosin head attaches to actin, pulling actin towards centre of sarcomere
Define motor unit
Motor neuron and all muscle fibres supplied by it
What type of receptor is muscle spindle?
Mechanosensitive proprioceptor
What do muscle spindles detect
Changes in muscle length
