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The function of the T tubules is to:
A) bind the Ach neurotransmitter
B) remove Ca++ from the cytoplasm
C) permit the AP (action potential) to reach the terminal cirstence
D) bind the myofilaments together to form the sacromere
E) energize the myosin ATPase
C) permit the AP (action potential) to reach the terminal cirstence
The activation gate (voltage sensitive gate) for Na+ is stilumated to open when _________ and closes when ___________.
A) threshold voltage is reached/ the inactivation gate closes
B) threshold voltage is reached/ membrane potential is below threshold
C) threshold voltage is reached/ the equilibrium potential is reached
D) Ach binds/ Ach unbinds
E) Ach binds/K+ starts to leave
B) threshold voltage is reached/ membrane potential is below threshold
Voltage gated Ca++ ion channels are found:
A) at the neuromuscular junction (NMJ)
B) in the T tubule
C) in the terminal cisternae
D) a and c
E) all over the plasma membrane in cardiac muscle fibers
D) a and c
The slowest gate to open during depolarization phase an action potential is:
A) K+ voltage gate
B) Na+ activation (voltage) gate
C) Na+ inactivation gate
D) none, all open at the same time
A) K+ voltage gate
In a relaxed sacromere which of the following is NOT true?
A) myosin is not bound to actin
B) troponin lacks Ca++
C) the myosin head is able to bind a new ATP
D) the myosin head is in its high energy state and erect position
E) the actin binding site for myosin is covered
C) the myosin head is able to bind a new ATP
Recruitment causes:
A) a and c
B) an increase of the frequency of action potential in a motor unit
C) more motor neurons that innervate that muscle to be excited
D) a greater percentage of the fibers in the muscle to contract
E) a longer duration to the contraction for each fiber
A) a and c
Which subtype of skeletal muscle fiber would be recruited first and would fatigue last?
A) fast glycolytic
B) fast oxidative
C) slow oxidative
C) slow oxidative
Author
lonelygirl
ID
265137
Card Set
Exam 2
Description
Biology 103A
Updated
2014-03-05T09:42:32Z
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