This lesson covers:
- How we breathe in and out
- The bell jar model
- Measuring lung volume
Mechanisms of breathing in and out
Our ribs and diaphragm help us breathe.
Breathing in happens when:
- The diaphragm contracts and moves down, increasing the volume in our chest.
- The ribcage moves up and out, helping make even more space.
- This makes the pressure inside the chest decrease and air comes rushing into our lungs.
Breathing out happens when:
- The diaphragm relaxes and moves up decreasing volume in our chest.
- The ribcage moves down and in, making less space in our chest.
- This increases the pressure inside the chest and air gets pushed out of our lungs.
The bell jar model
The bell jar model is a simple way to see how breathing happens.
Steps in the bell jar breathing model:
- Pulling down the rubber sheet is like the diaphragm moving down . This creates more space inside the bell jar.
- The increase in space lowers the pressure inside the bell jar.
- The lower pressure causes air to rush into the balloons, making them expand.
- Letting go of the rubber sheet reduces the space inside the bell jar, and is similar to our diaphragm moving up.
- Less space causes the pressure to increase, pushing air out of the balloons, similar to how air is pushed out of our lungs.
Measuring lung volumes
Lung volume is about how much air we can breathe in or out in one go.
- Lung volume is different for everyone. Your height and health can change how much air your lungs can hold.
- We can measure lung volume with a tool called a spirometer, which records how much air you breathe in and out.
- The spirometer shows us this information in a chart called a spirogram.
Practice Quiz
1. How do we breathe in and out?
Answer: Breathing in (inhalation) occurs when the diaphragm contracts and moves down, and the ribcage moves up and out, increasing the volume in the chest and decreasing the pressure, causing air to rush into the lungs. Breathing out (exhalation) happens when the diaphragm relaxes and moves up, and the ribcage moves down and in, decreasing the chest volume and increasing the pressure, pushing air out of the lungs.
2. What is the diaphragm and its role in breathing?
Answer: The diaphragm is a dome-shaped muscle located below the lungs. It plays a crucial role in breathing by contracting and flattening during inhalation to increase chest volume and relaxing during exhalation to decrease chest volume.
3. How does the ribcage contribute to breathing?
Answer: The ribcage moves up and out during inhalation to increase chest volume and down and in during exhalation to decrease chest volume, aiding in the pressure changes needed for air movement.
4. What happens to the pressure inside the chest during inhalation?
Answer: During inhalation, the increase in chest volume decreases the pressure inside the chest, causing air to rush into the lungs.
5. What happens to the pressure inside the chest during exhalation?
Answer: During exhalation, the decrease in chest volume increases the pressure inside the chest, pushing air out of the lungs.
6. What is the bell jar model?
Answer: The bell jar model is a simple representation of how breathing works. It consists of a bell jar, balloons, and a rubber sheet that simulates the diaphragm’s movement to show volume and pressure changes during breathing.
7. How does the bell jar model demonstrate inhalation?
Answer: Pulling down the rubber sheet in the bell jar model increases the volume inside the jar, decreasing the pressure and causing the balloons (representing lungs) to expand as air rushes in.
8. How does the bell jar model demonstrate exhalation?
Answer: Releasing the rubber sheet in the bell jar model decreases the volume inside the jar, increasing the pressure and causing the balloons to deflate as air is pushed out.
9. What is lung volume?
Answer: Lung volume refers to the amount of air that the lungs can hold during different phases of the breathing cycle, including tidal volume (normal breath), inspiratory reserve volume, expiratory reserve volume, and residual volume.
10. How is lung volume measured?
Answer: Lung volume is measured using a spirometer, a device that records the amount of air inhaled and exhaled. The data is displayed on a spirogram.
11. What is a spirometer?
Answer: A spirometer is a medical device used to measure lung volumes and capacities, including the amount of air inhaled and exhaled during normal and forced breathing.
12. What is a spirogram?
Answer: A spirogram is a chart or graph produced by a spirometer that shows the volume of air inhaled and exhaled over time, helping to assess lung function.
13. What factors can affect lung volume?
Answer: Factors affecting lung volume include age, gender, height, health, and fitness levels.
14. Why is lung volume important?
Answer: Lung volume is important for assessing respiratory health and diagnosing conditions like asthma, chronic obstructive pulmonary disease (COPD), and restrictive lung diseases.
15. What is tidal volume?
Answer: Tidal volume is the amount of air inhaled or exhaled during a normal breath, typically around 500 milliliters in adults.
16. What is inspiratory reserve volume?
Answer: Inspiratory reserve volume is the additional amount of air that can be inhaled after a normal inhalation, typically around 2,500-3,000 milliliters in adults.
17. What is expiratory reserve volume?
Answer: Expiratory reserve volume is the additional amount of air that can be exhaled after a normal exhalation, typically around 1,000-1,200 milliliters in adults.
18. What is residual volume?
Answer: Residual volume is the amount of air remaining in the lungs after a forceful exhalation, typically around 1,200 milliliters in adults.
19. What is vital capacity?
Answer: Vital capacity is the total amount of air that can be exhaled after a maximal inhalation, including tidal volume, inspiratory reserve volume, and expiratory reserve volume.
20. What is total lung capacity?
Answer: Total lung capacity is the maximum amount of air the lungs can hold, including vital capacity and residual volume, typically around 5,800 milliliters in adults.
21. What is the difference between ventilation and respiration?
Answer: Ventilation is the physical process of moving air in and out of the lungs, while respiration is the biochemical process of exchanging gases (oxygen and carbon dioxide) in the lungs and tissues.
22. What is the role of the alveoli in the respiratory system?
Answer: The alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled.
23. How does the body regulate breathing?
Answer: Breathing is regulated by the respiratory center in the brainstem, which responds to changes in carbon dioxide, oxygen, and pH levels in the blood.
24. What are the signs of healthy lung function?
Answer: Signs of healthy lung function include normal lung volumes, efficient gas exchange, and the ability to perform physical activities without excessive shortness of breath.
25. What are common respiratory disorders?
Answer: Common respiratory disorders include asthma, chronic obstructive pulmonary disease (COPD), pneumonia, bronchitis, and lung cancer.
26. How can lung health be maintained?
Answer: Lung health can be maintained by avoiding smoking, reducing exposure to pollutants, exercising regularly, maintaining a healthy diet, and getting regular medical check-ups.
27. What is the effect of smoking on the lungs?
Answer: Smoking damages the lungs by causing inflammation, reducing lung function, increasing the risk of respiratory infections, and leading to chronic conditions like COPD and lung cancer.
28. How does physical exercise impact lung capacity?
Answer: Regular physical exercise can improve lung capacity, enhance respiratory muscle strength, and increase the efficiency of oxygen uptake and carbon dioxide removal.
29. What is the role of the pleura in the respiratory system?
Answer: The pleura are two layers of membrane that surround the lungs and line the chest cavity, providing lubrication and reducing friction during breathing movements.
30. What are the symptoms of asthma?
Answer: Symptoms of asthma include wheezing, shortness of breath, chest tightness, and coughing, often triggered by allergens, exercise, or cold air.
31. What is chronic obstructive pulmonary disease (COPD)?
Answer: COPD is a chronic inflammatory lung disease that causes obstructed airflow from the lungs, leading to symptoms like breathing difficulty, cough, mucus production, and wheezing.
32. How is lung function tested?
Answer: Lung function is tested using spirometry, which measures the amount and speed of air a person can inhale and exhale, helping to diagnose and monitor respiratory conditions.
33. What is forced vital capacity (FVC)?
Answer: Forced vital capacity (FVC) is the total amount of air that can be forcibly exhaled after taking the deepest breath possible, measured during spirometry.
34. What is forced expiratory volume in one second (FEV1)?
Answer: Forced expiratory volume in one second (FEV1) is the amount of air that can be forcibly exhaled in the first second of a breath, used to assess lung function and diagnose obstructive airway diseases.
35. What is the significance of the FEV1/FVC ratio?
Answer: The FEV1/FVC ratio is used to diagnose obstructive and restrictive lung diseases. A low ratio indicates obstructive lung disease, while a normal or high ratio with reduced lung volumes indicates restrictive lung disease.
36. What is tidal breathing?
Answer: Tidal breathing is the normal, relaxed breathing pattern involving the inhalation and exhalation of a small amount of air (tidal volume).
37. How does breathing change during exercise?
Answer: During exercise, breathing rate and depth increase to meet the higher oxygen demands and to remove excess carbon dioxide produced by active muscles.
38. What is hyperventilation?
Answer: Hyperventilation is rapid or deep breathing that exceeds the body’s need for oxygen, leading to decreased carbon dioxide levels in the blood and causing symptoms like lightheadedness and tingling.
39. What is hypoventilation?
Answer: Hypoventilation is slow or shallow breathing that leads to increased carbon dioxide levels in the blood, potentially causing symptoms like fatigue and confusion.
40. How does altitude affect breathing?
Answer: At high altitudes, lower oxygen levels in the air can make breathing more difficult, leading to increased breathing rate and depth to compensate for reduced oxygen availability.
41. What are the benefits of diaphragmatic breathing?
Answer: Diaphragmatic breathing, or deep belly breathing, improves oxygen intake, reduces stress, and enhances relaxation by engaging the diaphragm more fully during breathing.
42. What is respiratory rate?
Answer: Respiratory rate is the number of breaths taken per minute. The normal range for adults is 12-20 breaths per minute.
43. What is the function of the nasal passages in breathing?
Answer: The nasal passages filter, warm, and humidify the air before it enters the lungs, enhancing respiratory efficiency and protecting the lower airways from irritants.
44. What is the role of surfactant in the lungs?
Answer: Surfactant is a substance produced in the lungs that reduces surface tension in the alveoli, preventing their collapse and ensuring efficient gas exchange.
45. What is bronchitis?
Answer: Bronchitis is an inflammation of the bronchial tubes, often caused by infections or irritants, leading to symptoms like cough, mucus production, and difficulty breathing.
46. What is the function of the larynx in the respiratory system?
Answer: The larynx, or voice box, protects the airway during swallowing, produces sound for speech, and facilitates breathing by regulating airflow to the lungs.
47. What is the impact of allergies on breathing?
Answer: Allergies can cause inflammation and narrowing of the airways, leading to symptoms like wheezing, shortness of breath, and coughing, particularly in conditions like allergic asthma.
48. What is pulmonary fibrosis?
Answer: Pulmonary fibrosis is a condition characterized by the thickening and scarring of lung tissue, leading to reduced lung function and difficulty breathing.
49. How does obesity affect breathing?
Answer: Obesity can reduce lung volume and compliance, increase the work of breathing, and contribute to conditions like obstructive sleep apnea and obesity hypoventilation syndrome.
50. What are the signs of respiratory distress?
Answer: Signs of respiratory distress include rapid breathing, shortness of breath, cyanosis (bluish skin), use of accessory muscles for breathing, and changes in mental status.