Final answer:
The medulla oblongata is part of the brainstem and is responsible for many reflex centers associated with complex visceral reflexes, including those that control breathing, heart rate, and digestion.
Step-by-step explanation:
The part of the brain that contains many of the reflex centers for complex visceral reflexes is the medulla oblongata. The medulla oblongata, along with the midbrain and the pons, are parts of the brainstem which connects the rest of the brain to the spinal cord. These structures coordinate essential autonomous functions such as breathing, heart rate, and digestion.
Additionally, the medulla oblongata is integral in regulating crucial functions including swallowing, blood pressure, and the control of heart and blood vessel activity. The brainstem overall is crucial for coordinating motor control signals sent from the brain to the body, and integrates both sensory and motor information. It consists of the midbrain, medulla oblongata, and the pons, and it coordinates motor control signals sent from the brain to the body.