chapter 10 part 2 muscular system needs to be reviewed missing info

Question 1

Depolarization & Generating an Action Potential
1. Na+ enters the cell, and the resting potential is?
2.If the stimulus is strong enough, an action potential is?

Answer 1

1. decreased

2. initated

Question 2

Propagating the Action Potential

1.  Polarity reversal of the initial patch of sarcolemma changes the ?
2. Voltage-regulated Na+ channels now ?in the adjacent patch causing it to ?
3. Thus, the action potential travels rapidly along the ?
4. Once initiated, the action potential is? and ultimately results in the contraction of a ?

Answer 2

1. permeability of the adjacent patch
2. open, depolarize
3. sarcolemma
4. unstoppable, muscle

Question 3

Repolarization
1. Immediately after the depolarization ? passes,the sarcolemma permeability ?
2.?channels close and ?channels open
3. ?diffuses from the cell, restoring the ?
4.?occurs in the same direction as depolarization, and must occur before the?
5.The ionic concentration of the resting state is restored by the ?
6.A brief action potential of 1-2 ms leads to contraction for ~100+ms
7.Action potential is over long before signs of muscle action are obvious.
8. During this latent period between initiation of action potential and the beginning of muscle
shortening, what occurs.

Answer 3

1. wave, changes
2. Na+, K+
   3.K+, electrical polarity of the sarcolemma
3. repolarization, muscle can be stimulated again (refractory period)
   5.Na+-K+ pump
   6.
   7.
   8.excitation-contraction coupling

Question 4

the final trigger for contraction is

Answer 4

Rise in intracellular Ca2+ levels

Question 5

is the sequence of events that leads to sliding of

myofilaments to shorten the muscle.

Answer 5

Excitation-contraction coupling

Question 6

The three phases of a muscle twitch are:

Answer 6

Latent period – first few milliseconds after stimulation when excitation-contraction
coupling is taking place
 Contraction period – cross bridges actively form and the muscle shortens
 Relaxation period – Ca2+ is reabsorbed into the SR, and muscle tension goes to zero

Question 7

Muscle contraction can be graded in 2 ways:

Answer 7

1. by changing frequency of stimulation

2. by changing strength of stimulus