... or glands, survive. Other brain cells die.Sometimes just parts of cells die off. For instance, many more synapses are formed than needed between neurons and other neurons, muscles and glands. ... and glands. Those synapses that are used remain and get stronger, the other synapses detach, and the axons shrivel and die. Which brain cells and which of their synapses survive depends on their ... the zygote divides, first into 2, then 4, 8, 16 and more cells, some of those daughter cells are on one pole (e.g., containing maternal chemicals) and the others on the other pole (e.g., not containing...