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
What happens to the lungs during inspiration?
Lungs are stretched during inspiraton
What happens to intrapulmonary volume during inspiration?
Intrapulmonary volume increases during inspiration
What happens to intrapulmonary pressure during inspiration?
Intrapulmonary pressure decreases during inspiration
- Pressure drops from 0 mm Hg to -1 mm Hg
During inspiration where do the gases (air) travel to and how?
Air (gases) travel into lungs down its pressure gradient
How much air (gases) is in the lungs during inspiration is needed before beginning expiration?
Until the intrapulmonary pressure is 0
Equal to atmospheric pressure
What are the two primary muscles used for expiration?
Muscles used in expiration
- Internal intercostals
- Rectus abdominus
What is the sequence of events for expiration?
- Inspiratory muscles relax
- Diaphragm rises
- Rib cage descends due to gravity
- Thoracic cavity volume decreases
- Elastic lungs recoil passively
- Intrapulmonary volume decreases
- Intrapulmonary pressure rises (to +1 mm Hg)
- Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0
What happens to the inspiratory muscles during expiration?
Inspiratory muscles relax during expiration
- Diaphragm rises
- Diaphragm moves superiorly as it relaxes
- Ribcage descends due to gravity
- Ribs and sternum depressed as external intercostals relax
What happens to the thoracic cavity volume during expiration?
