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.
A calendar day is a 24 hour period between two consecutive midnights. During a day, we experience both day time as well as night time. Day time, which is literally referred to as day, is the part of the day when the Sun is up in the sky. In other words, a day starts with the sun rise and ends with the sun set.