Answer:
1.An action potential is conducted deep into the muscle fiber by the T tubule.
3.The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
4.Calcium ions diffuse into the sarcoplasm around the myofibril.
2.Calcium ions bind to troponin.
5.The troponin-tropomyosin complex moves exposing active sites.
Explanation:
The arrival of a nerve impulse at synaptic end bulbs stimulates the release of acetylcholine into the synaptic cleft. The acetylcholine binds to its receptors located on the motor end-plate followed by the opening of ion channels to allow the small cations such as Na+ to enter the muscle fiber and make it positive.
The change in the membrane potential triggers the action potential that propagates along the sarcolemma into the T tubules. The action potential stimulates the release of calcium ions from the sarcoplasmic reticulum into the sarcoplasm.
The released calcium ions combine with troponin. Binding of calcium ions to troponin stimulates conformational change in troponin that makes the tropomyosin to shift away from the myosin-binding sites of actin.
The myosin heads join the free binding sites to form cross-bridges leading to contraction of muscle fiber.
Option B, faulting, is the right answer.
Layers of strata in the crust of the earth usually skim along each other. Seldom resistance or blockage generates this manner to end until enough force builds up to succeed whatever the opposing energy is. Faulting is the manner through which this pressure forces the levels to sustain their action, often creating cracks in the associated strata, and inducing earthquakes and trembling in the development of extreme pressure relief
Solution:
the name of the sheath that encases axons to protect them and increase the speed of communication between neurons is known as myelin sheath.
It is known as the insulating envelope of myelin that surrounds the core of a nerve fiber or axon and that facilitates the transmission of nerve impulses, formed from the cell membrane of the Schwann cell in the peripheral nervous system and from oligodendroglia cells. medullary sheath.
Thu the right answer is myelin sheath