In the closed-circuit UBA, which component does O2 encounter first after leaving the cylinder?

In the closed-circuit UBA, which component does O2 encounter first after leaving the cylinder?

• A. the inhalation hose
• B. the breathing bag
• C. the demand valve
• D. the connecting line

Answer: (D)

In a closed-circuit UBA, follow the path of the gas from the cylinder through the system. Oxygen leaves the cylinder and enters the unit via the inlet connecting line. This line is the first component the gas encounters after leaving the cylinder. Once inside, the gas moves into the breathing loop (the breathing bag/loop), where it is stored and circulated. When you inhale, the demand valve opens, sending gas from the loop through the inhalation hose to your mouthpiece. So the initial interface the O2 meets after leaving the cylinder is the connecting line.

In a closed-circuit UBA, follow the path of the gas from the cylinder through the system. Oxygen leaves the cylinder and enters the unit via the inlet connecting line. This line is the first component the gas encounters after leaving the cylinder. Once inside, the gas moves into the breathing loop (the breathing bag/loop), where it is stored and circulated. When you inhale, the demand valve opens, sending gas from the loop through the inhalation hose to your mouthpiece. So the initial interface the O2 meets after leaving the cylinder is the connecting line.