What structure controls both heartbeat and breathing?

The medulla oblongata is a critical part of the brainstem that plays a key role in regulating both heartbeat and breathing. It contains vital centers that manage autonomic functions, ensuring that these essential life-sustaining processes operate seamlessly.

The cardiac center in the medulla adjusts the heart rate in response to the body’s needs, such as during exercise or rest. Simultaneously, the respiratory center regulates the rate and depth of breathing, responding to levels of carbon dioxide and oxygen in the blood. This dual function is vital for maintaining homeostasis, as it coordinates the cardiovascular and respiratory systems to meet the body's metabolic requirements.

In contrast, the cerebral cortex is primarily involved in higher-level brain functions like reasoning and voluntary movements rather than automatic processes such as heartbeat and breathing. The spinal cord primarily facilitates the transmission of signals between the brain and the body but does not have the same regulatory functions regarding vital autonomic control. The thalamus primarily acts as a relay station for sensory and motor signals, which does not extend to directly controlling heart rate or respiration. Thus, the medulla is specifically equipped for this crucial role in maintaining life.