Numerous antiepileptic medications, such phenytoin, have been designed to block voltage-gated sodium channels (VGSC) in neuronal membrane. In addition, multiple toxins and pharmacological modulators work by attaching to various biophysical states of the VGSC to cause their effects. Depending on how modulatory agents act, some VGSC states are stabilized or destabilized, altering the channel's biophysical properties. The first anticonvulsant to successfully treat epileptic disorders without causing undesirable side effects such as brain drowsiness was phenytoin.
Phenytoin has been indicated to block high-frequency neuronal activity potentials from the inner vestibule of the pore, as demonstrated by electrophysiological research and site-directed mutation.
Frequency and voltage both affect phenytoin binding.
There are theories that phenytoin interferes with the late sodium current that sustains depolarizations in epilepsy by blocking non-inactivated channels.
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Biodiversity generally refers to the variety and variability of life on Earth. According to the United Nations Environment Programme(UNEP), biodiversity typically measures variation at the genetic, species, and ecosystem level.[1] Terrestrial biodiversity tends to be greater near the equator,[2] which seems to be the result of the warm climateand high primary productivity.[3] Biodiversity is not distributed evenly on Earth, and is richest in the tropics. These tropical forest ecosystems cover less than 10 percent of earth's surface, and contain about 90 percent of the world's species.[4] Marine biodiversitytends to be highest along coasts in the Western Pacific, where sea surface temperature is highest, and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity.[5]Biodiversity generally tends to cluster in hotspots,[6] and has been increasing through time,[7][8] but will be likely to slow in the future.[9]
Rapid environmental changes typically cause mass extinctions.[10][11][12] More than 99.9 percent of all species that ever lived on Earth, amounting to over five billion species,[13] are estimated to be extinct.lstimates on the number of Earth's current species range from 10 million to 14 million,[f which about 1.2 million have been documented and over 86 percent have not yet been described] More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.[18]The total amount of related DNA base pairson Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes.[19] In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).[20] In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor (LUCA) of all organisms living on Earth.[21]
The age of the Earth is about 4.54 billion years.[22][23][24] The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago,[25][26][27] during the Eoarchean Era after a geological crust started to solidify following the earlier molten HadeanEon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia.[28][29][30] Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland.More recently, in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.[32][33] According to one of the researchers, "If life arose relatively quickly on Earth .. then it could be common in the universe.
decreased and then increased after major waves of mass extinctions
Answer is.
Answer:
Corpus callosum
Explanation:
Corpus callosum is the red part of the brain that has a “C” shape. The corpus callosum, which is made up of over 200 million of neural fibers, links both hemispheres of the brain (the left and right brain) together, which allows for coordination and complex communication between both in order for the brain to function properly.
This structure usually starts forming about 12 weeks after conception of a child, and continues to develop up to about 12 years of age of the child.
The main function of the corpus callosum is the ensuring of uninterrupted flow of information, and the integration of complex information and tasks such as motor, sensory and cognitive functions between both hemispheres of the brain.
Answer:
The heart pumps blood through the lungs. In the lungs the blood receives oxygen and releases carbon dioxide. Then the heart pumps this oxygen-rich blood from the lungs to your cells. When the oxygen-rich blood gets to the cells, the cells receive the oxygen and release the carbon dioxide.
The cells in our bodies need oxygen to stay alive. Carbon dioxide is made in our bodies as cells do their jobs. The lungs and respiratory system allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide in the air breathed out.
Explanation:
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