What component of the gas machine combines nitrous oxide and oxygen for patient administration?

The component of the gas machine that combines nitrous oxide and oxygen for patient administration is the flowmeter. This device is essential in regulating and accurately measuring the flow of gases delivered to the patient. The flowmeter allows the dental assistant or practitioner to set the specific ratios of nitrous oxide to oxygen based on the patient's needs, ensuring safe and effective sedation during procedures.

A gas hose functions as a conduit for the delivery of the gases from the source to the patient but does not mix the gases or measure the flow. The reservoir bag provides a flexible storage space for gas, allowing the patient to draw on it as needed, but it doesn't regulate the flow or mix the gases. A mask is used to deliver the gas mixture to the patient but does not play a role in the combination or measurement of the gases. Thus, the flowmeter is the key component responsible for combining and controlling the delivery of nitrous oxide and oxygen effectively.