R E V I E W
S H E E T
LAB TIME/DATE _______________________
Mechanics of Respiration
1. For each of the following cases, check the column appropriate to your observations on the operation of the model lung.
Diaphragm pushed up
In the size of the balloons (lungs)
In direction of air flow
In internal volume of the bell jar
In internal pressure
Diaphragm pulled down
Out of lungs ✓
Into lungs ✓
Out of lungs
2. Base your answers to the following on your observations in question 1. 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 why this is so. ↓ thoracic volume, ↑ pressure. Gases move in the direction that tends to equalize pressure inside and outside the “container.”
3. Activation of the diaphragm and the external intercostal muscles begins the inspiratory process. What effect does contraction of these muscles have on thoracic volume, 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 dimensions.
4. What was the approximate increase in diameter of chest circumference during a quiet inspiration? (student data) During forced inspiration? (student data)
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What temporary physiological advantage is created by the substantial increase in chest circumference during forced inspiration? 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.
5. The presence of a partial vacuum between the pleural membranes is integral to normal breathing movements. What would happen 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.
How is this condition treated medically? Air is withdrawn (chest tube) and the chest is closed.
6. Which of the respiratory sounds is heard during both inspiration and expiration? Bronchial Which is heard primarily during inspiration? Vesicular
7. Where did you best hear the vesicular respiratory sounds? Heard over most of the lung area.
Respiratory Volumes and Capacities—Spirometry or BIOPAC®
8. 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 (~1100 ml) Volume of air that can be expired forcibly after a normal expiration: expiratory reserve (~1200 ml) Volume of air that is breathed in and out during a normal respiration: tidal volume (~500 ml) Volume of air that can be inspired forcibly after a normal inspiration: inspiratory reserve (~2700–2800 ml) Volume of air corresponding to TV ϩ IRV ϩ ERV: vital capacity (~4800 ml) 9. Record experimental respiratory volumes as determined in the laboratory. (Corrected values are for the recording spirometer only.)
Average TV: (student data)
Average ERV: (student data)
Corrected value for TV: (student data)
Corrected value for ERV: (student data)
Average IRV: (student data)
Average VC: (student data)
Corrected value for IRV: (student data)
Corrected value for VC: (student data)
% predicted VC: (student data)
MRV: (student data)
FEV1: (student data)
Review Sheet 37...
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