Most of the development of sperm occurs in a large multinucleate cell. Testosterone, but not estrogen, is required for sperm development. Developing sperm contain surface-bound Fas ligand, a protein that triggers apoptosis of lymphocytes. Potassium channels help set the resting membrane potential of the cell. Vesicles are more numerous in the presynaptic junction than in the postsynaptic junction.
Protein synthesis occurs in the post-synaptic junction.
The hypothalamus controls circadian rhythms. Local blood vessels allow hormones released by the hypothalamus to reach the pituitary directly without going through the rest of the body. Growth hormone is made by the pituitary. Most sensory nerves do not spontaneously generate action potentials. The senses of taste and smell are functionally similar, using similar transduction mechanisms.