Question 1: Define the term 'alveoli' and explain their role in the respiratory system.

Answer: Alveoli are tiny air sacs in the lungs where gas exchange occurs; they facilitate the transfer of oxygen into the blood and removal of carbon dioxide from the blood.

Question 2: Describe the pathway air follows from the nose to the alveoli in the lungs.

Answer: Air enters through the nose or mouth, passes through the trachea, then into the bronchi, which branch into smaller bronchioles, and finally reaches the alveoli where gas exchange occurs.

Question 3: Which structure separates the two lungs and what is its function?

Answer: The mediastinum separates the two lungs and contains the heart, trachea, and other vital structures.

Question 4: Explain how the structure of alveoli maximizes gas exchange efficiency.

Answer: Alveoli have a large surface area and thin walls, which allow for efficient diffusion of gases between the air and blood.

Question 5: Calculate the volume of oxygen (in liters) that would be absorbed if a person takes in 500 mL of air, assuming 21% of air is oxygen and 20% of that oxygen diffuses into the blood during one breath.

Answer: 0.021 liters

Question 6: Identify the variables in an experiment testing the effect of different oxygen concentrations on lung capacity. List one control variable.

Answer: Independent variable: oxygen concentration; Control variable: type of breathing exercise or participant's age.

Question 7: Describe a safety precaution to consider when conducting experiments involving lung capacity measurements.

Answer: Ensure proper sterilization of equipment and avoid inhaling harmful substances during the experiment.

Question 8: In a scenario where a patient's lungs have reduced alveolar surface area, what effect would this have on gas exchange? Explain briefly.

Answer: Reduced alveolar surface area decreases the efficiency of gas exchange, leading to less oxygen entering the blood and less carbon dioxide being removed.

Question 9: Which technological advancement helps monitor lung function in patients, and how does it aid medical diagnosis?

Answer: Spirometers measure lung capacity and airflow, helping doctors diagnose respiratory conditions like asthma or COPD.

Question 10: Explain how smoking can damage lung tissue and affect the structure of alveoli.

Answer: Smoking introduces toxins that damage the alveolar walls, causing them to lose elasticity and reducing surface area, which impairs gas exchange and can lead to diseases like emphysema.

Question 11: Describe how the structure of the lungs is adapted for efficient gas exchange in mammals.

Answer: The lungs have a large number of alveoli with thin walls and a rich blood supply, increasing surface area for diffusion. The moist environment facilitates gas transfer, and the extensive capillary network ensures efficient oxygen uptake and carbon dioxide removal.