Explanation:

- Medulla: Part of the brainstem, the medulla controls vital functions such as breathing, heart rate, and blood pressure.

- Thalamus: Located above the brainstem, the thalamus acts as a relay station for sensory information, directing it to the appropriate areas of the brain.

- Pons: Another component of the brainstem, the pons plays a critical role in regulating sleep and respiratory processes, and in relaying signals between different parts of the brain.

- Pinna: This is not part of the brain. The pinna refers to the external part of the ear, which gathers and directs sound waves into the ear canal.

So, the part that is NOT a part of the brain is the pinna.