Review Sheet 24: Respiratory System Physiology PDF

# Review Sheet 24: Respiratory System Physiology ## Mechanics of Respiration 1. **Based on your answers to the following on your observations of the operation of the model lung.** - **Under what internal conditions does air tend to flow into the lungs?** ↑ thoracic volume and ↓ pressure....

# Review Sheet 24: Respiratory System Physiology ## Mechanics of Respiration 1. **Based on your answers to the following on your observations of the operation of the model lung.** - **Under what internal conditions does air tend to flow into the lungs?** ↑ thoracic volume and ↓ pressure. - **Under what internal conditions does air tend to flow out of the lungs? Explain.** ↓ thoracic volume; ↑ pressure. Gases move in the direction that tends to equalize pressure inside and outside the container. 2. **Activation of the diaphragm and the external intercostal muscles begins the inspiratory process. What results from the contraction of these muscles, and how is this accomplished?** ↑ thoracic volume. The diaphragm moves inferiorly, increasing the superior/inferior dimension; the ribs swing up and out, increasing the lateral and anterior/posterior dimension. 3. **What was the approximate increase in diameter of chest circumference during a quiet inspiration?** 2-3 inches. **During forced inspiration?** 5-7 inches. **What temporary, physiological advantage does the substantial increase in chest circumference during forced inspiration create?** Increases the thoracic volume more, therefore, creates a greater negative internal pressure, causing the gases to rush in quickly. Also, more "fresh" air reaches the alveoli. 4. **The presence of a partial vacuum between the pleural membranes is necessary for proper inflation of the lungs. What would occur if an opening were made into the chest cavity, as with a puncture wound?** Destroys the partial vacuum in the pleural space and the lung on the affected side collapses. ## Respiratory Volumes and Capacities: Spirometry 5. **Write the respiratory volume term and the normal value that is described by the following statements:** - **Volume of air present in the lungs after a forceful expiration.** Residual volume (~1100ml) - **Volume of air that can be expired forcibly after a normal expiration: ** Expiratory reserve (~1200ml) - **Volume of air that is breathed in and out during a normal respiration.** Tidal volume (~500ml) 6. **Record experimental respiratory volumes as determined in the laboratory.** - **Average TV** 500 ml - **Average ERV** 3400 ml - **Average VC** 1400 ml - **Average IRV** 1000 ml ## Factors Influencing Rate and Depth of Respirations 7. **Where are the neural control centers of respiratory rhythm?** Medulla oblongata and pons. 8. **Based on pneumograph reading of respiratory variation, what was the rate of quiet breathing?** Initial testing: 12 breaths/min. **Record observations of how the initial pneumograph recording was modified during the various testing procedures described below. Indicate the respiratory rate, and include comments on the relative depth of the respiratory peaks observed.** | Test performed | Observations | |---|---| | Talking | Respiratory rate becomes irregular during talking | | Yawning | Yawning reflected by extremely deep prolonged inspiration | | Laughing | Respiratory rate becomes irregular; respiratory depth may be loud or soft depending on the nature of the laugh | | Standing | Regular rhytym and increased rate | | Running in place | Increased rate and depth of breathing | | Swallowing water | Respiration ceases during the period of the time of swallowing | | Coughing | Respiration rate becomes irregular and marked by expirations during coughing | | Lying down | Regular rhythm and regular rate; depth decreases | | Concentrating | Respiratory rate is regular unless punctuated by intervals of apnea in individuals who hold their breath when concentrating | 9. **Student data:** - **Breath-holding interval after a deep inhalation.** 45 sec - **Length of recovery period.** 30 sec - **Breath-holding interval after a forceful expiration.** 20 sec - **Length of recovery period.** 40 sec **After breathing quietly and taking a deep breath (which you held), did you feel an urge to inspire or to expire?** Expire. **After exhaling and then holding your breath, did you want to inspire or expire?** Inspiration. 10. **Observations after hyperventilation:** Breathing slowed, felt light-headed, slight tingling in fingers, and took deeper breaths during recovery. 11. **Blood CO₂ levels and blood pH are related. When blood CO₂ levels increase, the pH increases. Explain what changes might occur in the blood's pH if the breathing rate increased or decreased. ** If the breathing rate increases, CO₂ levels decrease, and pH increases. If the breathing rate decreases, CO₂ levels increase, and pH decreases. 12. **Length of breath holding after hyperventilation:** 30sec. **Why does hyperventilation produce apnea or a reduced respiratory rate?** Hyperventilation washes CO₂ out of the blood. Since CO₂ is the major chemical stimulus for inspiration, the desire or drive to breathe is decreased. 13. **Observations for rebreathing breathed air:** Breathing became faster to compensate. **Why does rebreathing breathed air increase the respiratory rate?** CO₂ (exhaled) accumulates in the bag; this stimulates increased force and rate of respiration. 14. **Do the following factors generally increase (indicate with I) or decrease (indicate with D) the respiratory rate and depth?** | | Respiratory Rate and Depth | |---|---| | Increase in blood CO₂ | I | Decrease in blood O₂ | I | Increase in blood pH | D | Decrease in blood pH | I | | **Did it appear that CO₂ or O₂ had a greater effect on modifying the respiratory rate?** 15. **Where are sensory receptors sensitive to changes in O₂ levels in the blood located?** Aortic bodies in the aortic arch and carotid bodies at the bifurcation of the common carotid artery.