Which three components make up the brain stem?

The brain stem is a critical structure in the central nervous system, responsible for many autonomic functions essential for survival. It is composed of three main parts: the midbrain, pons, and medulla.

The midbrain plays a vital role in vision, hearing, motor control, sleep/wake cycles, and temperature regulation. The pons facilitates communication between different parts of the brain, particularly between the cerebellum and the cerebrum, and is also involved in regulating sleep and respiration. The medulla oblongata is crucial for controlling vital functions such as heart rate, blood pressure, and the respiratory rhythm.

In contrast, the other options refer to different parts or functions of the brain that do not collectively comprise the brain stem. The first option lists lobes of the cerebral cortex, not components of the brain stem. The second option includes structures that are part of the forebrain and not the brain stem. The last option mentions types of brain matter and the spinal cord, which is distinct from the brain stem itself. Thus, identifying midbrain, pons, and medulla as the components of the brain stem underscores the interconnectedness of these structures in maintaining essential body functions.