Muscle Contraction Flashcards
What is skeletal muscle used for?
Voluntary movements
What are the 2 contractile proteins?
Actin and myosin
What are actin filaments?
Twisted chain of monomers
What are myosin filaments?
Ordered bundles with heads at one end
What’s the order of muscle organisation going from smallest to largest?
Sarcomeres, myofibrils, muscle giver, bundle of muscle fibres, muscle
What are Z lines?
Border adjacent sarcomeres. Provide an anchor for actin filaments and for titin (holds mysoin filaments in position)
How do you take a muscle to bits?
Cold glycerol or triton-X - removes cell and lipid membranes
What happens to myosin molecules in dilute salt?
They assemble into bipolar filaments
Who discovered sliding filament theory?
Huxley and Huxley
What did the Huxley’s find
Length of thick and thin filaments doesn’t change when muscles contract, the extent of their overlap does though
What did Huxley Gordon and Julian discover?
That force produced by a muscle fibre is proportional to the amount of overlap
What does the length/tension curve look like?
A slightly distorted to the right dome
What carries electrical excitation into the muscle fibre?
T-tubules
What does depolarisation of T-tubules cause?
Ca++ released from sarcoplasmic reticulum
What stops muscle contraction?
When electrical excitation stops the Ca++ is actively transported back into the sarcoplasmic reticulum
