A baby suckling at the nipple sends nerve signals to sensory neurons in the hypothalamus.

Oxytocin is made by neurosecretory cells and stored in the posterior pituitary.

When oxytocin circulates to target cells in the breast, it triggers smooth muscle contraction and release of milk.

The milk encourages more suckling at the nipple.

The anterior pituitary also releases prolactin, stimulating milk production in the breast.