Respiratory System Physiology Flashcards
Tidal Volume (TV)
Amount of air inhaled or exhaled with each breath under resting conditions
500 mL
Inspiratory Reserve Volume (IRV)
Amount of air that can be forcefully inhaled after a normal tidal volume inhalation
3100 mL
Expiratory Reserve Volume (ERV)
Amount of air that can be forcefully exhaled after a normal tidal volume exhalation
1200 mL
Residual Volume (RV)
Amount of air remaining in the lungs after a forced exhalation
1200 mL
What are the respiratory volumes?
- Tidal volume (TV)
- 500 mL
- Inspiratory reserve volume (IRV)
- 3100 mL
- Expiratory reserve volume (ERV)
- 1200 mL
- Residual volume (RV)
- 1200 mL
Total lung capacity (TLC)
Maximum amount of air contained in the lungs afters a maxium inspiratory effort
TLC = TV + IRV + ERV + RV
~6000 mL
Vital capacity (VC)
Maximum amount of air that can be expired after a maximum inspiratory effort
VC = TV + IRS + RV
(Should be 80% of TLC)
~4800 mL
Inspiratory capacity (IC)
Maximum amount of air that can be inspired after a normal expiration
IC = TV + RV
~3600 mL
Functional residual capacity (FRC)
Volume of air remaining in the lungs after a normal tidal volume expiration
FRC = ERV + RV
~2400 mL
What are the respiratory capacities?
- Tidal lung capacity (TLC)
- TLC = TV+IRV+ERV+RV
- ~6000 mL
- Vital capacity (VC)
- VC = TV+IRV+ERV
- ~4800 mL
- Inspiratory capacity (IC)
- IC = TV + IRV
- ~3600 mL
- Functional residual capacity (FRC)
- FRC=ERV+RV
- ~2400 mL
What keeps the lungs inflated?
Negative Pressure
What are the two primary muscles of inspiration?
- Diaphragm
- External intercostals
What is the sequence of events for inspiration?
Inspiration
- Inspiratory muscles contract (diaphragm descents; rib cage rises)
- Thoracic cavity volume increases
- Lungs stretched; intrapulmonary volume increases
- Intrapulmonary pressure drops (to -1 mm Hg)
- Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is equal to 0
- Equal to atmospheric pressure
During inspiration what happens to the inspiratory muscles?
Inspiratory muscles contract
- Diaphragm descends
- Ribs elevate and sternum flares as external intercostals contract
During inspiration what happens to the volume in the thoracic cavity?
Thoracic cavity volume increases during inspiraton