10/17 Excitation-Contraction Coupling - Rogers 2017 Flashcards
What characteristic of muscles states that they can be stretched back to resting length? 6
Extensibility
What is a muscle fiber synonymous with? 10
Muscle cell
Where is calcium stored within skeletal muscle? 11
Sarcoplasmic reticulum
What is found within thin filaments (actin)? 12
Actin
Troponin
Tropomyosin
What is resting membrane potential? 13
-80 —> -90mv
What kind of acetylcholine receptor is found within skeletal muscle? 15
Nicotinic (inotropic) acetylcholine receptors
How is calcium released into muscle fibers? 16
VGCC dihydroyridine receptors (DHP) once stimulated pulls on ryanodine receptors (RYR) located on sarcoplasmic reticulum
Ca2+ enters cytosol
Once an action potential is completed how is Ca2+ removed from the cytoplasm? 17
SERCA (ATPase) pump Ca2+ in Sarcoplasmic Reticulum
NCX (3Na+/1Ca2+ exchanger) pumps Ca2+ to extracellular space
What changes when contraction of a muscle occurs? 18
I band —> zone shortens
A band —> zone does not change
What is the name of the ATP binding site on Myosin? 19
S1 - binding domain
What covers the Myosin binding sites on actin? 20
Tropomyosin
What happens after the power stroke and is involved in re-cocking? 28
After power stroke ATP binds myosin which causes myosin release from actin
ATP hydrolyzed to ADP + Pi, But doesn’t release either
Myosin re-cocked
What is a twitch? 35
A single minimal stimulus
What describes repeated stimulation? 36
Tetanus (>80 stimuli/s)
What describes Slow Twitch (type I) fibers? 40
Resilient
High oxidative capacity
[mitchondria] high, red
