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Marysya12 [62]
3 years ago
14

Describe the process of skeletal muscle contraction by assembling the following 10 events in the proper order in paragraph form.

Begin with an action potential traveling down a motor neuron to the neuromuscular junction and end with the muscle in its relaxed state. (5 points) 1) T and T system undergoes a conformational change, exposing the myosin binding sites on actin 2) myosin heads/cross bridges bind to actin and flex, shortening the sacromere 3) calcium ions bind to the T and T system 4) actin filaments are pulled toward the center of the sacromere, shortening the muscle fiber 5) muscle fiber is stimulated at the neuromuscular junction triggering an action potential 6) myosin head/cross-bridges bind to actin 7) APs travel down the T-tubules to the sarcoplasmic reticulum 8) in response to an AP, calcium ions are released into the cytosol/space around the myofibrils 9) calcium ions actively transported into the sarcoplasmic reticulum 10) myosin head continues to attach, flex, release, extend, and reattach as long as calcium ions are present
Biology
1 answer:
balu736 [363]3 years ago
3 0

5) muscle fiber is stimulated at the neuromuscular junction triggering an action potential  

7) APs travel down the T-tubules to the sarcoplasmic reticulum  

Released acetylcholine (due to action potential within motor neuron) from the motor neuron initiates depolarisation within the sarcolemma, which is spread through the muscle fibre via T tubules.

8) in response to an AP, calcium ions are released into the cytosol/space around the myofibrils

Depolarisation causes the sarcoplasmic reticulum to release calcium ions necessary for the contraction

3) calcium ions bind to the T and T system

1) T and T system undergoes a conformational change, exposing the myosin binding sites on actin  

6) myosin head/cross-bridges bind to actin

The binding sites for the myosin heads located on actin, are covered by a blocking complex (troponin and tropomyosin) that can be unblocked by the calcium binding

2) myosin heads/cross bridges bind to actin and flex, shortening the sacromere  

4) actin filaments are pulled toward the center of the sacromere, shortening the muscle fiber  

As the individual sarcomeres become shorten the muscle fibres as a whole contracts

10) myosin head continues to attach, flex, release, extend, and reattach as long as calcium ions are present

9) calcium ions actively transported into the sarcoplasmic reticulum  

Relaxation of a muscle fiber occurs when a Ca ions are pumped back into the sarcoplasmic reticulum .

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bagirrra123 [75]

The correct answer is rapids and waterfalls.  

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The rapids are generally produced where the resilient bedrock limits a stream to a narrow channel and forces an enhancement in the velocity of water.  

On the other hand, waterfalls are produced where the fast-flowing water negotiates a geologic contact amid the more resilient and less resistant layers of rock, or through a fault, which has analogized distinct kinds of rocks. Or it can be said that waterfalls usually produce at the end of a series of rapids.  


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3 years ago
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Need Help due in a 1 hour : Earth Science
egoroff_w [7]

Answer:

C). Seafloor spreading.

Explanation:

Paleomagnetism is characterized as the 'study of the account of direction and strength of magnetic fields of the Earth in sediments, rocks, etc.' The hypothesis that was authenticated by using this study would be 'seafloor spreading' by displaying that magnetic reversal as strips of rotating polarity in gradually disseminating seafloor. This description of magnetic stripping by employing paleo-magnetism made the scientists believe that alternate crusts are being frequently made under ocean/sea. Thus, <u>option C</u> is the correct answer.

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All glands in the body, such as salivary glands and the pancreas, are derived from which type of tissue
tiny-mole [99]

Answer:

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Suppose the great, green galoofus lizard has 28 chromosomes in the nucleus of its unfertilized eggs. Predict how many chromosome
Amiraneli [1.4K]

Answer: 56

Explanation:

Because an unfertilized egg has half the chromosomes of a fertilized egg. The fertilized egg then splits, and continues splitting until the lizard is born. Always remember, whenever a question  talking about an unfertilized egg, it has half the chromosomes of a fertilized egg. One more side note, it doesn’t matter what body part you talk about. A skin cell will have the same number, and identical chromosomes compared to a heart cell. (So long as it’s the same organism, if it isn’t, but part of the same species, it will have the same number of chromosomes, but it may have a unique set of chromosomes). If you want me to go into detail, I can, just respond to this answer.

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According to the fossil record found across this area of the coastal United States, what conclusion can we make about area A? A)
pogonyaev
The answer is b Area A was completely underwater in the past.<span> None of the other conclusions can be drawn; you need more information. You DO know that area A was once completely underwater though.\</span>
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