What regulates chewing, swallowing and breathing?

The medulla oblongata regulates all these processes. The medulla oblongata is the lowest part of the brain and the lowest part of the brainstem. The length of the medulla oblongata is connected by pores with the midbrain and is continuous from behind with the spinal cord, with which it merges in the opening at the base of the skull.
The medulla oblongata is divided into two main parts: the frontal part and the posterior part, also known as the tegmentum. The medulla oblongata contains a pair of triangular structures called pyramids, within which lie the pyramidal pathways.