Questions and Answers
Describe the movement of the diaphragm during inspiration and expiration. How does diaphragmatic motion influence thoracic dimensions?
During inspiration, the diaphragm contracts and descends, increasing thoracic dimensions. During expiration, the diaphragm relaxes and ascends, decreasing thoracic dimensions.
Describe the motions of the ribs and sternum during forced inspiration.
Superior ribs (primarily 2-6) move anteriorly and upward, increasing anterior-posterior thoracic diameter. The inferior ribs move laterally and upward, increasing the transverse dimension.
Describe the motions of the ribs and sternum during forced expiration.
Superior ribs (2nd - 6th) move posteriorly and downward, decreasing anterior-posterior thoracic diameter, while the inferior ribs move medially and downward, decreasing the transverse dimension.
What is the main action performed by the external intercostal muscles during respiration?
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What is the main action performed by the internal intercostal muscles during respiration?
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Why is it critical that the integrity (tone) of the intercostal muscles be maintained?
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Study Notes
Diaphragmatic Movement
- During inspiration, the diaphragm contracts and moves downward.
- This contraction increases thoracic dimensions, allowing for greater lung expansion.
- Upon expiration, the diaphragm relaxes and moves upward, decreasing thoracic dimensions.
Rib and Sternum Motions in Forced Inspiration
- Superior ribs (primarily 2nd to 6th) move anteriorly and upward.
- This motion increases the anterior-posterior thoracic diameter.
- The sternal body is elevated along with the superior ribs.
- Inferior ribs move laterally and upward, enhancing the transverse thoracic dimension.
Rib and Sternum Motions in Forced Expiration
- Superior ribs (2nd to 6th) move posteriorly and downward.
- This action decreases the anterior-posterior thoracic diameter.
- The sternal body moves downward in conjunction with the superior rib motion.
- Inferior ribs shift medially and downward, reducing the transverse thoracic dimension.
External Intercostal Muscles
- Responsible for elevating the ribs during forced inspiration.
- Contribute to increasing thoracic volume for inhalation.
Internal Intercostal Muscles
- Main action is to lower the ribs during forced expiration.
- They help in reducing thoracic volume to expel air.
Importance of Intercostal Muscle Integrity
- Maintaining muscle tone prevents intercostal spaces from bulging during expiration or collapsing during inspiration.
- Essential for resisting pressure changes within the thoracic cavity, particularly important during the breathing cycle.
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Description
This set of flashcards covers key concepts related to respiratory mechanics, focusing on diaphragmatic movement during inspiration and expiration. It also explores the motions of the ribs and sternum during forced inspiration, delving into how these movements affect thoracic dimensions.
