Muscle Flashcards
Give the troponin molecules and their function
Troponin I - Inhibitory - prevents calcium binding
Troponin C - Bind to Calcium
Troponin T - Binds to tropomyosin
What is the name given to the part between to Z lines?
The sarcomere is between the 2 Z lines
True or false: The M line is in the middle of the I band
False
M line is the middle of the H band and the A band
Z line is the middle of the I band
True or false: The I bands are un-overlapped actin
True
I bands = light bands
Actin is thinner than myosin and makes up the I bands
Which band is made up of un-overlapped myosin?
a) I band
b) A band
c) H band
d) M band
H zone
M line in the middle
Explain the sliding filament mechanism in relation to the changes in band lenghts during muscle contraction.
The H bands get smaller (myosin only bands) but the A bands (actin) doesnt change size. This proves that the shortening of the muscle is not due to the shortening of the actin filaments
Explain the advantage of T tubules in muscles
Cells are big, thick and long. Membrane is where the depolarisation occurs to initiate contraction.They conduct electrical impulses to the throughout cell (every sarcomere); the electrical impulse signals for the release of Ca2+ from adjacent terminal cisternae
Describe the process that leads to skeltal muscle contraction
Be stimulated by a nerve ending
Propagate an electrical current, or action potential, along its sarcolemma
Have a rise in intracellular Ca2+ levels, the final stimulus for contraction
Which period of muscle contraction is being described: This is the time elapsed from the application of a stimulus to the beginning of the contraction (when calcium ions are being released)
a) Latent period
b) Contraction period
c) Relaxation period
a) Latent period
Which period of muscle contraction is being described: Active transport of Ca++ back into the sarcoplasmic reticulum and degradation of acetylcholine
a) Latent period
b) Contraction period
c) Relaxation period
c) Relaxation period
