L76 - Physiology of Airway Obstruction Flashcards
What are four features associated with Airflow Obstruction
- Increased Sensation of Breathing
- Increased Respiratory Muscle Effort
- Active Exhalation
Longer time to inspire and expire
Increased sensation of breathing is often described as _______.
If it seems appropriate it is accepted as a __________.
If it appears inappropriate, it is perceived as a _________.
Breathlessness
Sensation
Symptom
During inspiration, which nerves act on the diaphragm?
Phrenic
During inspiration, which nerves act on the intercostal muscles.
Intercostal nevres
How does inspiration occur and does it use negative or positive pressure?
The diaphragm and intercostal muscles increase the volume int he thorax, generating a negative intra-pulmonary pressure, drawing air into the lungs.
What is the work of breathing (wob) at rest.
Low, approximately 3%
During ______ the intra-alveolar pressure is less than Patm.
Durign ______ the alveloar pressure is more then Patm
Inspiration
Expiration
When is intra-alveolar pressure equal to Patm
At the end of inspiration AND expiration
What is lower, intra-pleural pressure or intra-alveolar pressure and why?
Intra-pleural pressure is always lower than intra-alveolar pressure due to elastic recoil of the lungs and chest wall.
Why is the work of breathing (WOB) substantially increased if airway obstruciton is present?
The inspiratory muscles need to generate higher pressures to overcome the obstruction to airflow (resistive WOB).
What are three consequences of increased work of breathing (WOB)?
- Recruitment of accessory muscles of inspiration
- Increased oxygen consumption by respiration muscles
- Risk of respiratory muscle fatigue, if the airway obstruction is severe
What are the accessory muscles of inspiration?
Scalene and Sternomastoid
