lecture 9 - skeletal system

Question 1

what are skeletal muscle functions?

Answer 1

produce movement, maintain posture, stabilise joints, generate heat and store nutrient reserves

Question 2

how do muscles move?

Answer 2

Muscles are attached to bones via tendons – tendon pulls on the bone – lever system and causes the muscle to move

Question 3

what is the gross structure of the skeletal muscle?

Answer 3

epimysium – on the muscle – connective muscle, dense tissue which protects muscles from tension, protects friction against other muscles
perimysium – many muscle fibres, depends on the muscle
endomysium – within muscles - a connective tissue

Sarcolemma – beneath the endomysium – when the muscle is activated via nerve signals – action potential transmitted along nerve signals – exciatory contractions, transmits the wave of depolarisation as it has a membrane – allows a contraction to take place in the muscle fibre

Question 4

what is sarcolemma depolarisation?

Answer 4

both types of channels, release of a neurotransmitter which binds – causes depolarisation to spread – initiates the release of calcium ions

Question 5

what is excitation-contraction coupling?

Answer 5

Arrives at the neuromuscular junction – release of a neurotransmitter – across the junction, binds to receptors on the sarcolemma – spreads into the t tubules
increase in discharge frequency – more ca released which binds to more tropin molecules – more actin
Many motor units – takes place in more muscle fibres