External Intercostals

Definition

The external intercostals are a group of skeletal muscles located between the ribs that play a crucial role in the process of breathing, gas exchange, and the movement of the abdominal wall.

5 Must Know Facts For Your Next Test

1. The external intercostals are responsible for the elevation of the ribs during inhalation, which increases the volume of the thoracic cavity and facilitates the flow of air into the lungs.
2. The contraction of the external intercostals causes the ribs to move upward and outward, increasing the anteroposterior and lateral dimensions of the thoracic cavity.
3. The external intercostals work in conjunction with the diaphragm to create negative pressure within the thoracic cavity, which draws air into the lungs during inspiration.
4. The external intercostals also play a role in the movement of the abdominal wall, as their contraction can assist in the expulsion of air during forceful exhalation.
5. Dysfunction or impairment of the external intercostal muscles can lead to respiratory issues, such as difficulty breathing or inefficient gas exchange.

Review Questions

• Explain the role of the external intercostal muscles in the process of breathing.
  • The external intercostal muscles are responsible for the elevation of the ribs during inhalation. Their contraction causes the ribs to move upward and outward, increasing the volume of the thoracic cavity. This increase in volume creates a negative pressure within the thoracic cavity, which draws air into the lungs. The external intercostals work in conjunction with the diaphragm to facilitate the flow of air during inspiration, making them a crucial component of the breathing process.
• Describe how the external intercostal muscles contribute to gas exchange within the body.
  • The external intercostal muscles play an indirect role in gas exchange by facilitating the movement of air into and out of the lungs. During inspiration, the contraction of the external intercostals increases the volume of the thoracic cavity, creating negative pressure that draws air into the lungs. This allows for the exchange of oxygen and carbon dioxide between the air in the lungs and the blood. Similarly, during forceful exhalation, the external intercostals can assist in the expulsion of air, which helps to remove carbon dioxide from the body. Therefore, the proper functioning of the external intercostal muscles is essential for maintaining efficient gas exchange within the respiratory system.
• Analyze the relationship between the external intercostal muscles and the movement of the abdominal wall.
  • The external intercostal muscles not only contribute to the movement of the thoracic cavity during breathing but also influence the movement of the abdominal wall. When the external intercostals contract, they can assist in the expulsion of air during forceful exhalation, which is facilitated by the contraction of the abdominal muscles. This coordinated movement of the thoracic and abdominal regions helps to optimize the efficiency of the respiratory system. Additionally, the external intercostals may play a role in the movement of the abdominal wall during activities that require increased intra-abdominal pressure, such as coughing, sneezing, or bearing down. Therefore, the external intercostal muscles are integral to the integrated function of the respiratory and abdominal systems.

Related terms

Intercostal Muscles: The intercostal muscles are a group of skeletal muscles located between the ribs that facilitate the expansion and contraction of the thoracic cavity during breathing.

Inspiration: The process of drawing air into the lungs, which is facilitated by the contraction of the diaphragm and external intercostal muscles.

Expiration: The process of expelling air from the lungs, which is facilitated by the relaxation of the diaphragm and contraction of the internal intercostal muscles.