2 Bolser Infrastructure of Skeletal Muscle Flashcards
Myofibrillar proteins are mainly made of what 2 things
Myosin
Actin
What are structural features of Myosin
2 polypeptieds in a-helix arrangement
Globular head region
S-1 segment has ATP and actin binding sites
What degree do myosin heads project off at
60 degrees
What makes up actin
G actin
F actin
What does actin do
binds myosin
Activates myosin ATPase
What does troponin do
Ca binds to it which regulates the movement of tropomyosin
What happens if ATP doesn’t bind to myosin
Rigor mortis
What happens if ATP binds to myosin
Cross bridge detaches
What happens when the cross bridge binds to actin
Ca is released
What is the length tension relationship
Force is proportional to crossbridge overlap
Definition of motor unit
single motoneuron and muscle fibers it innervate
Innervation ratio
number of muscle fibers innervated by a motoneuron determines level of control
What type of receptor is the acetylcholine receptor in skeletal muscle
Nicotinic
What does muscle action potential trigger
changes in DHP/Ryanodine receptor like proteins
What causes the symptoms of hypocalcemia
Reduced Ach release
Membrane depolarization due to loss of Ca membrane mediated stablization
