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>
Explanation:
Organic polymers are macromolecules composed of many repeating monomer units. Both synthetic and natural polymers play a crucial role in everyday life. Polysaccharides, polypeptides, and polynucleotides are the main types of biopolymers in living cells.
Answer:
An inflammation of the vagina most commonly caused by Candida, called <u>candidiasis</u>, is characterized by some degree of vaginal itching; however, <u>candidiasis</u> does not appear to induce vaginal inflammation and is most likely due to a reduction in Lactobacillus species.
Because the organism is distributed across the world, and isn't seen anymore, scientists can conclude tat they must have evolved. They can compare one species to the fossils they may have found, and determine that they were related. Then by looking at the species on another part of the world compare the same fossils to other animals and determine that they are similar, sharing a common ancestor.
Answer:
Ecological succession refers to the changes taken place in a forest over a particular period of time.
Succession is usually influenced by environmental factors such as water regimes, soil type, climate, vegetation history, and invasive species.
Humans interventions affect all of the above-mentioned factors.
Human activities such as fragmentation of forests, clearing of forests for agricultural practices, construction of dams, civilization, logging et cetera drastically reduce the biodiversity of a forest.
This reduction of biodiversity forms the foundation for a secondary succession of a forest.
