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:
false
Explanation:
"Empirical" means "based on observation or experience," according to the Merriam-Webster Dictionary. Empirical research is the process of finding empirical evidence. If there are flaws in the way that empirical data is collected, the research will not be considered valid.
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[5] Free calcium metal is too reactive to occur in nature. Calcium is produced in supernova nucleosynthesis.
Answer:
I believe that the correct answer is d. Interglacial Winds
Explanation:
Please mark as brainiest ! Hope this helps!
Answer:
B) lighting a match
Explanation:
a chemical change is a chemical reaction involving the rearrangement of atoms. While a physical change can often be reversed, a chemically change typically cannot.
Always remember, if something is being lit on fire then it is a chemical change, since fire breaks the bonds in between the atoms.
Freezing water is a physical change because it can be reversed and does not alter the substance, which is water. a change in state i always a physical change
tearing up a piece of paper is a physical change since nothing on a molecular level has changed. its still paper.
Dissolving sugar in water is a <em>homogenous mixture</em>, meaning that it looks uniform without, however it is still only sugar and water, so it is a physical change.
