NMDA reÂ·cepÂ·tor. a type of glutamate receptor that participates in excitatory neurotransmission and also binds N-methyl-d -aspartate; may be particularly involved in the cell damage observed in individuals with Huntington disease.
â Ultramafic magma is extremely low in silica, with less than 45 percent of the same, but rich in heavier elements like iron and magnesium. It can have a temperature of about 2732 Â°F. It has very low viscosity and thus, its eruptive behavior is gentle.
Quick Answer. The Earth's mantle is made primarily of solid rock. All of this rock is comprised of a variety of oxides. Their atomic elements include oxygen, silicon and magnesium.