3.3.2 Gas exchange: Human Gas Exchange System

Front

What is the primary function of the alveoli in the human gas exchange system?

Back

To provide a large surface area for gas exchange

Answer explanation

The primary function of the alveoli is to provide a large surface area for gas exchange, allowing efficient transfer of oxygen and carbon dioxide between the lungs and bloodstream.

Front

Which structure connects the trachea to the lungs?

Back

Bronchi

Answer explanation

The bronchi are the main passageways that connect the trachea to the lungs. They branch off from the trachea and lead directly into each lung, allowing air to flow in and out.

Front

What role does the diaphragm play in the mechanism of breathing?

Back

It contracts to increase the volume of the thoracic cavity

Answer explanation

The diaphragm contracts during inhalation, increasing the volume of the thoracic cavity. This decrease in pressure allows air to flow into the lungs, making it essential for the breathing process.

Front

Which muscles work antagonistically to aid in breathing?

Back

External and internal intercostal muscles

Answer explanation

The external and internal intercostal muscles work antagonistically during breathing. The external intercostals help expand the ribcage during inhalation, while the internal intercostals assist in forced exhalation.

Front

What is the equation for pulmonary ventilation rate (PVR)?

Back

PVR = tidal volume × breathing rate

Answer explanation

The pulmonary ventilation rate (PVR) is calculated by multiplying the tidal volume (the amount of air per breath) by the breathing rate (number of breaths per minute). Thus, the correct equation is PVR = tidal volume × breathing rate.

Front

Tidal volume: 500 mL, Breathing rate: 15 breaths/min. What is the pulmonary ventilation rate?

Back

7,500 mL/min

Answer explanation

To find the pulmonary ventilation rate, multiply tidal volume (500 mL) by breathing rate (15 breaths/min). 500 mL/breath * 15 breaths/min = 7,500 mL/min, which is the correct answer.

Front

What is the primary function of the trachea in the respiratory system?

Back

To transport air to the bronchi

Answer explanation

The primary function of the trachea is to transport air to the bronchi, allowing for airflow to the lungs. It does not exchange gases, absorb oxygen, or produce mucus as its main role.

Front

Best description of the alveolar epithelium?

Back

Thin and permeable

Answer explanation

The alveolar epithelium is characterized as thin and permeable, allowing for efficient gas exchange in the lungs. This property is essential for oxygen and carbon dioxide diffusion, making it the best description.

Front

What happens to the pressure in the thoracic cavity when the diaphragm contracts?

Back

It decreases

Answer explanation

When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity. According to Boyle's law, as volume increases, pressure decreases. Therefore, the pressure in the thoracic cavity decreases.

Front

Which of the following is NOT a part of the human gas exchange system? Alveoli, Bronchioles, Esophagus, Trachea

Back

Esophagus

Answer explanation

The esophagus is part of the digestive system, not the gas exchange system. The alveoli, bronchioles, and trachea are all essential components involved in the process of gas exchange in the lungs.