The conduction of nerve impulses relies upon the movement of positively-charged ions across the nerve cell membrane. The entry of sodium into the cell produces a wave of positive charge that travels down the length of an axon. Then chemicals called neurotransmitters are secreted out of the end of the axon onto the next nerve in the series (the postsynpatic nerve). This narrow space in between neurons is called the synapse. These neurotransmiiters released by the presynaptic nerve bind to receptors on the postsynaptic nerve. The binding of these receptors opens up channels in this second nerve's membrane that allow sodium ions to enter the nerve cell and initiate another wave of positive charge, and so on... The nerve signal can only move as fast as these ions and neurotransmitters can diffuse to generate this process.
<span>As a professional athlete repeats a given activity many times over, the nerve cells "upregulate" their receptors, meaning that they produce additional receptors to put in the membrane. This is just a natural reaction to the nerve being repeatedly stimulated in the same way over and over. When neurotransmitter is secreted from the presynaptic neuron, there are more receptors on the postsynaptic neuron for it to bind, more channels open up, more ions enter in a shorter time and build up positive charge to create the impulse faster, and so the overall effect is faster. </span>
<span>Additionally, there are sheaths of fatty tissue (called myelin) that insulate the charge in the neuron and allow it to be conducted faster. As people age, these sheaths can start to degrade, making the nerve cell more "leaky" and causing the impulse to be conducted more slowly. </span>
Answer:
The factors which remained constant are as follows -
- material used as the membrane
- amount of substances used
- number of trials
The factors which have shown variation are as follows -
- molecule size (large starch molecules vs. small glucose molecules)
- whether the molecules diffused through the membrane (tubing)
Explanation
Some factors with in the experiments remained constant from the point of starting of the experiment to its end. While some factors were varied to study its impact on the experiment rate of progression or on the final product formed. Thus , out of the following given factors, the ones that remained constant are -
- material used as the membrane
- amount of substances used
- number of trials
The factors which have shown variation are as follows -
- molecule size (large starch molecules vs. small glucose molecules)
- whether the molecules diffused through the membrane (tubing)
Answer:
provide flexibility
Explanation:
According to my research on studies conducted by various medical professionals, I can say that based on the information provided within the question the role of elastic fibers is to provide flexibility. Elastic fibers contain elastin, a protein that acts like rubber and allows them to stretch and recoil like rubber bands, making them very flexible.
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Can you show the picture of the question please?
Answer:
Explanation:
1. can generate energy – Both , In landfills methane gas is produced which is used to generate electricity, like wise heat energy produced in incinerator is also used for producing energy
2. emits toxins through combustion – Incinerators produce dioxins which is a dangerous chemical
3. drains liquids into the ground – Land fill, leachate is a common issue with all landfill site.
4. releases greenhouse gases – Both, methane and other carbon gases are produced in both landfill and incinerators
5. requires a substantial amount of land – land fill site , needs a large land to dump the city waste
6. generate ash – Incenerator only
