RS Lecture 3 and 4 - Ventilation & Gas Transport and Exchange Flashcards
What are normothermic ex vivo ventilated perfused lungs?
No restriction to movement as no chest wall and expand freely in all directions
What is minute ventilation?
Volume of air expired in one minute or per minute
What is Resp rate?
Frequency of breathing per minute
What is Alveolar ventilation?
Volume of air reaching the resp zone
What is respiration?
Process of generating ATP either with an excess of O2 (aerobic) or a shortfall (anaerobic)
What is anatomical dead space?
Capacity of airways incapable of undertaking gas exchange
What is alveolar dead space?
Capacity of airways that should be able to undertake gas exchange but cannot
What is physiological dead space?
Equivalent to the sum of alveolar and anatomical dead space
What is hypoventilation?
Deficient ventilation of the lungs - unable to meet metabolic demand > Acidosis (^CO2)
What is hyperventilation?
Excessive ventilation of lungs atop of metabolic demands > Alkalosis (decreased CO2)
What is hyperpnoea?
^ depth of breathing to meet metabolic demand
What is hypopnea?
Decreased depth of breathing - inadequate to meet metabolic demand
What is apnoea?
Cessation of breathing
What is dyspnoea?
Difficulty in breathing
What is bradypnoea?
Abnormally slow breathing rate
What is tachypnoea?
Abnormally fast breathing rate
What is orthopnea?
Positional difficulty in breathing (mainly when lying down)
What are the 2 components of the chest wall?
Bone, muscle, fibrous tissue AND lungs
What way does the rib cage recoil?
Outwards
What way do the lungs recoil?
Inwards
What is the functional residual capacity?
At the end of tidal expiration: Elastic recoil of lungs inwards = ER of ribs outwards
What is needed to remove the FRC equilibrium?
Muscular effort to push equilibrium to one way/another
What is the volume of the pleural cavity?
Fixed and contains protein-rich pleural fluid
What is the pressure of the pleural cavity?
Negative
What happens when we do a full inspiration (in terms of walls/pressure)?
Chest wall expands and pulls diaphragm down and lungs need to be pulled with it - negative pressure in pleural cavity pulls lungs with chest wall
What can happen to disturb the connection between lungs and chest wall?
Lungs will deflate - caused by puncture in chest wall/lung so pleura will fill with air or blood, so elastic recoil of lung takes over and causes collapse
Whats the difference between time taken in development of haemo and pneumothorax?
Haemo overtaking f elastic lung recoil occurs much slower
What is tidal breathing?
The amount of inspiration and expiration that meets metabolic demand - usually nasal
How is the Functional Residual Capacity measured?
Trough of a tidal breath to 0
Why can you not fully empty the lungs?
Surfactant in alveoli prevents them from sticking together and not reopening
What is the residual volume?
The volume that remains in the lungs after full expiration
What are the four main volumes of air?
Tidal, Inspiratory reserve, Expiratory reserve and Reserve (can be combined to capacities)
What is TLC?
Full volume of lungs - TV+IRV+ERV+RV
What is vital capacity?
How much air is in the range we’re able to inspire/expire - TLC-RV
What is functional residual capacity?
Vol of air in the lungs when recoil in ribs and lungs are in equilibrium - ERV+RV
What is inspiratory capacity?
How much air can be taken in on top of FRC - TV+IRV
What factors affect lung volumes and capacities?
Body size (HEIGHT, shape), sex, fitness, disease (pulm or neuro), age
What drives flow?
Pressure - from high to low
What unit is used when talking about lung volumes?
cmH2O
When does positive pressure breathing occur?
Atmospheric pressure is increased above Alveolar pressure such as in Ventilation, CPR