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: They read articles about photosynthesis. They investigate photosynthesis, energy storage molecules, and carbon in the sim. ... This process moves carbon from biotic to abiotic matter. Carbon dioxide in the biodome decreased because decomposers decreased which means there was a decrease in cellular respiration overall.
Explanation:
Blood is the fuel that keeps you going! Oxygenated blood is brought to organs and tissues via the arteries, while veins bring deoxygenated blood back to the heart to be replenished. The point is, without the respiratory system your blood would be useless.
The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart.
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Sexual reproduction increases the genetic variation within the population, because new individuals are made by randomly combining genetic material from two parents. Because only fit individuals reach sexual maturity and reproduce, the overall population tends toward increasing fitness in its environment.
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