What are neurotransmitters? What neurotransmitters are associated with depression? Schizophrenia? Pain reduction? Parkinson’s disease? Brain arousal? Muscle contractions?

Neurotransmitters are endogenous chemicals that are released by axon terminals of neurons into the synaptic junctions and act locally to control nerve cell functions.

•Imbalance of neurotransmitters such as serotonin,norepinephrine and dopamine have been linked with depression.

•Abnormal levels of neurotransmitter glutamate leads to changes in the level of Dopamine which can cause transition into psychosis.Dopamine has been implicated as possible cause of schizophrenia.

•Several transmitters are involved in analgesia system (pain suppression),especially involved are enkephalin and serotonin. When Serotonin are released and this causes local cord neurons ti secrete enkephalin,which is believed to cause both presynaptic and postsynaptic inhibition of pain fibres.

•Parkinson's disease also known as paralysis agitans results from widespread destruction of that portion of substantia nigra that sends dopamine-secreting nerve fibres to caudate nucleus and putamen this leads to decrease in dopamine.

•Acetylcholine is responsible brain arousal and muscle contraction.

i wish i could with all of them i can barley see the first one so here's the answer to the first one b

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.