8 Questions
What is the primary function of the diaphragm during inhalation?
To increase the volume of the chest cavity, allowing air to enter the lungs
What is the role of the external intercostal muscles during inspiration?
To pull the ribs outward and upward, assisting in inhalation
What happens to the diaphragm during expiration?
It relaxes and rises
What is the function of the scalene muscles during forced breathing?
To help elevate the ribs
What is the role of the internal intercostal muscles during expiration?
To pull the ribs inward and downward, assisting in exhalation
What happens to the intercostal muscles during inspiration?
They contract and pull the ribs outward and upward
What is the function of the accessory muscles during forced breathing?
To help elevate the ribs and sternum, and to rotate the scapula
What is the primary muscle of inspiration?
The diaphragm
Study Notes
Respiratory Muscles
Diaphragm
- Primary muscle of inspiration
- Dome-shaped muscle that separates the chest cavity from the abdominal cavity
- Contracts and relaxes to change the volume of the chest cavity
- Increases the volume of the chest cavity during inhalation, allowing air to enter the lungs
Intercostal Muscles
- Located between the ribs
- Two types:
- External intercostal muscles: assist in inspiration by pulling the ribs outward and upward
- Internal intercostal muscles: assist in expiration by pulling the ribs inward and downward
Accessory Muscles
- Used during forced breathing, such as during exercise or when the body is under stress
- Include:
- Scalene muscles: located in the neck and help to elevate the ribs
- Sternocleidomastoid muscles: located in the neck and help to elevate the sternum
- Pectoral muscles: located in the chest and help to elevate the ribs
- Serratus anterior muscles: located in the chest and help to rotate the scapula
Muscle Actions
- Inspiration:
- Diaphragm contracts and descends
- Intercostal muscles contract and pull the ribs outward and upward
- Accessory muscles contract and help to elevate the ribs and sternum
- Expiration:
- Diaphragm relaxes and rises
- Intercostal muscles relax and pull the ribs inward and downward
- Accessory muscles relax and help to lower the ribs and sternum
Respiratory Muscles
Diaphragm
- Primary muscle of inspiration, responsible for increasing the volume of the chest cavity during inhalation
- Dome-shaped muscle that separates the chest cavity from the abdominal cavity
- Contracts and relaxes to change the volume of the chest cavity
Intercostal Muscles
- Located between the ribs
- Two types:
- External intercostal muscles: assist in inspiration by pulling the ribs outward and upward
- Internal intercostal muscles: assist in expiration by pulling the ribs inward and downward
Accessory Muscles
- Used during forced breathing, such as during exercise or when the body is under stress
- Include:
- Scalene muscles: located in the neck and help to elevate the ribs
- Sternocleidomastoid muscles: located in the neck and help to elevate the sternum
- Pectoral muscles: located in the chest and help to elevate the ribs
- Serratus anterior muscles: located in the chest and help to rotate the scapula
Muscle Actions
- Inspiration:
- Diaphragm contracts and descends
- Intercostal muscles contract and pull the ribs outward and upward
- Accessory muscles contract and help to elevate the ribs and sternum
- Expiration:
- Diaphragm relaxes and rises
- Intercostal muscles relax and pull the ribs inward and downward
- Accessory muscles relax and help to lower the ribs and sternum
Learn about the primary muscles of respiration, including the diaphragm and intercostal muscles, and their roles in inspiration and expiration.
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