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>
<u>Answer:</u>
The Earth has got its tilted axis and this is the reason for different seasons to be formed. Communities are a set of population found in that particular area and are of two types.
A) Terrestrial (Land)
B) Aquatic (Water).
These communities to flourish need a perfect environment with a perfect season. Hence according to the season formed due to the tilted axis influences the terrestrial community which forms in that particular region and have the ability for the region specific community growth.
The terrestrial community of a tundra or desert or rain forest all depends on the particular season that can be formed due to the position of the earth facing the sun.
the answer is the beetle is neither harmed nor helped by the mite.
I believe the answer is delta.
