Which part of the brain controls vital functions such as heart rate and breathing?

The medulla oblongata is responsible for regulating vital functions such as heart rate and breathing. It is located in the brainstem, which is crucial for sustaining life as it oversees essential automatic functions. The medulla oblongata contains centers that control the rate and depth of breathing as well as the rhythm of the heartbeat. This makes it an integral part of the autonomic nervous system, which operates without conscious thought to maintain basic physiological processes necessary for survival.

In contrast, the cerebral cortex is involved in higher cognitive functions such as thought, judgment, and voluntary muscle movements. The cerebellum plays a role primarily in coordination and balance, aiding in muscle control and fine motor skills rather than autonomic functions. The thalamus functions primarily as a relay station for sensory and motor signals to the cerebral cortex and is not involved in regulating vital life functions like heart rate or respiration. Thus, the medulla oblongata is the correct answer due to its essential role in controlling these involuntary processes.