Respiratory Week 1 Flashcards
Are accessory muscles sufficient for ventilation?
No, we need the diaphragm
Describe what the diaphragm is doing during inspiration
Contracting and moving downward
Describe what the diaphragm is doing during expiration
Relaxing and moving upward
What are the muscles of inspiration?
Diaphragm (duh)
Secondary accessory muscles: SCM, scalenus, parasternal intercartilaginous muscles, external intercostals
What are the muscles of expiration?
Internal intercostals (except the parasternal intercartilaginous muscles) and the abdominal muscles (rectus abdominus, external oblique, internal oblique, transversus abdominus)
Do we do work during inspiration or expiration?
Inspiration
Expiration is passive
What comprises the conducting airways? What Z levels correspond to this?
Nasal sinuses, pharynx, larynx, trachea, bronchi, bronchiole, terminal bronchioles
Z levels: 0 to 16
What volume of air is held in the conducting airways?
150 mls
What is the airflow like in the conducting airways?
Generally turbulent/transitional
Trachea is really where the turbulence is
What Z levels comprise the alveolar/respiratory airways?
17 to 23
What volume of air is in the alveolar/respiratory airways during normal breathing?
2500-3000 mls
What is the airflow like in the alveolar/respiratory airways?
Laminar flow
Where in the conducting airways does cartilage disappear? What Z level is this?
At the bronchiole level
Z4
In order for passive diffusion to be effective, we need to maximize the _________ across which gases move
surface area (and the vast majority of lung surface area is in the aveolar airways)
Define tidal volume (Vt). What is a normal Vt?
The amount of air inhaled/exhaled with a normal breath from the resting level
~0.5 L
Define Expiratory Reserve Volume (ERV). What is a normal ERV?
The volume of air that can be expelled after normal tidal volume expiration
~2 L
Define Residual Volume (RV). What is a normal RV?
The amount of air that remains after maximal expiration
~1.2 L
Define Forced Vital Capacity (FVC). What is a normal FVC?
The amount of air which can be forcibly exhaled from the lungs after taking the deepest breath possible and factoring in the time component (“ceiling to floor”)
~5 L (usually 5 L per 5 seconds)
**Note: similar to Vital Capacity (VC) but with the time component
Define Vital Capacity (VC). What is a normal VC?
The volume of air that is exhaled after maximal inspiration
~5 L
VC = ERV + IRV + Vt
Define Total Lung Capacity (TLC). What is a normal TLC?
The maximum volume to which the lungs can be expanded
~6 L
TLC = VC + RV
Define Functional Residual Capacity (FRC). What is a normal FRC?
The amount of air left in the lungs after a tidal volume breath
~2.5 L
FRC = RV + ERV
Define Inspiratory Reserve Volume (IRV). What is a normal IRV?
The volume of air that can be inhaled after a normal inhalation
~2.5 L
Define Inspiratory Capacity (IC). What is a normal IC?
The amount of air that can be drawn into the lungs after normal expiration
~3 L
What three things can spirometry NOT measure?
Residual volume, total lung capacity, functional residual capacity