medulla oblongata

Meaning: The medulla oblongata is the lowest part of the brainstem and is continuous with the spinal cord. It belongs to the hindbrain, along with the pons and cerebellum. Its nuclei regulate vital functions that run without conscious effort: the rhythm of breathing, heart rate, blood pressure, and reflexes such as swallowing, coughing, sneezing, and vomiting. Sensory and motor tracts also pass through it on their way between the brain and spinal cord.

On the MCAT: The usual question gives a function or an injury and asks which structure is involved. Expect a matching set: medulla for autonomic and reflex control, pons for sleep, arousal, and relaying signals between the cerebellum and cerebrum, cerebellum for balance, coordination, and motor learning. A passage might describe a person whose thinking is intact but whose breathing or heart rhythm fails, or compare damage to the cortex with damage to the brainstem. Predict that brainstem damage threatens basic survival functions, while cortical damage often spares them and mainly affects thought, perception, and voluntary action.

Common confusion: Students mix the medulla up with the hypothalamus or the cerebellum. The hypothalamus (forebrain) sets homeostatic drives such as hunger, thirst, and temperature and links the nervous system to the endocrine system. The cerebellum is also in the hindbrain, but it fine-tunes movement. The medulla handles automatic vital reflexes.