Endocrine glands ( ductless glands ) are the glands responsible for the production of hormones. "Neurons" are the structural and functional units of the nervous system. Contraction of the uterus at the time of child birth brings about oxytocin release from the hypothalamus via the posterior pituitary which in turn causes dilatation of the cervix. This dilation further increases the oxytocin release by a positive feedback mechanism and the contraction of the uterus becomes stronger and cervix dilatation increases. This helps in normal vaginal delivery. Hence oxytocin is called birth hormone. The endocrine part of pancreas is called the Islets of Langerhans. It consists of alpha , beta and delta cells.