Neurotransmitters are formed in a presynaptic neuron and stored in small membrane-bound sacks, called vesicles, inside this neuron. When this neuron is activated, these intracellular vesicles fuse with the cell membrane and release their contents into the synapse, a process called exocytosis.
Modern timekeeping defines a day as the sum of 24 hours â but that is not quite correct. The Earth's rotation slows down over time. So in terms of solar time, most days are a little longer than 24 hours.
However, the mean solar day â the average length of a day, based on how long it takes Earth to rotate â is about 86,400.002 seconds long. Thatâs because Earthâs rotation is gradually slowing down a bit, due to a kind of braking force caused by the gravitational tug of war between Earth, the moon and the sun.