Though not the most common occurrence, Automation Engineers sometimes become Automation Engineering Managers, where the average income is $105K per year.
For example, the antrum of the stomach (gastric antrum) is a portion before the outlet, which is lined by mucosa and does not produce acid. The paranasal sinuses can be referred to as the frontal antrum, ethmoid antrum, and maxillary antrum.
Here, the cardia and body of the stomach relax to accommodate food that enters the stomach. Then the antrum (lower stomach) contracts rhythmically, mixing the food with acid and enzymes (stomach juices) and grinding the food down into small pieces so that it is more easily digested.