DeCoursey Introduction and Anatomy of respiratory System Flashcards
3 main functions of the respiratory system
- Gas exchange- get O2, Eliminate CO2 (primary)
- Metabolism
- Host defense
What is the respiratory quotient
RQ= Rate of CO2 production/rate of O2 consumption
RQ of Glucose, protein and Fat
Glucose= 1
Protein=.85
Fat- .7
Making the typical diet .8
RER
Respiratory Exchange Ratio= Rate of CO2 expired/Rate of O2 inspired
At rest should be the same as RQ= CO2 pdtion/O2 consumption
What are the typical values of V(dot) for CO2(expired) and O2(inspired)?
What is the percent difference?
We consume O2 faster than we produce CO2
O2= 250ml/min CO2= 200ml/min
this ends up resulting in 1% greater inspiration than expiration. The difference iis so small because most of the air we breath is nitrogen so of the total minute ventilation the 50ml/min variances is minimal
Components if the respiratory system
Control
- AIr pump (that gets air into the lungs)
- Gas exchange
- Gas transport O2 through Hb and CO2 as bicarbonate
Control(respiratory center in brain stem)
- CNS- rate and depth of breathing and with CV distribution of blood
- Chemoreceptors= sensitive to chemicals levels of O2, CO2 and pH- arterial PCO2 is the main determinant as the ventilation
3 main differences in hearrt and lung
What happens in each when a hole is poked?
- Heart has artery and vein while lung uses same sructures for in and out
- Heart has valves while lungs don’t because air needs to move in and out
3, Heart works by positive pressure by increasing pressure blood is forced out, lungs pump air in by contracting inspiration muscle expanding thoracic cavity lower pressure inside the lungs so air goes into the lungs
Heart hole= blood shooting out
Lung- air will come in
Muscle of inspiration
Muscles of expiration
Inspiration- external intercostal lifting ribs up and out and diaphragm which contracts downward expanding volume of thoracic cavity
Expiration- internal intercostals and accessory(SCM, scalenes, pec major and minor etc.)
Difference in active and passive for inspriation and expiration?
INspiration- active
Expiration- passive relaxation of inspiration muscles- can become active when increased breathing rate
Explain what happens in gas exchange
O2 from air goes to Hb to the cells
CO2 from cells into and from blood into air
Why do we need Hb and not just use blood serum?
Serum can hold abuot 3mlO2/LIter x5Liters= 15 but we need about 250ml O2/min.
Hb can hold 200mlO2/Min x%= 1000mlO2/min so much more than we need
How many levels of branching in lung
23 levels- Weibels level of branching
Conducting-movement of air 1-16 and respiratory zone (17-23- gas exchange)
remember that lung parenchyma are mostly air and the alveolar wall is packed with capillaries-max SA and minimal distance between the two
relation b/w Alveolar SA and ??? are direct
Metabolic Requirement of O2
Define Total lung capacity
Average Value
Breath in and totally fill lungs and amount in your entire respiratory system- 6L
Define Residual Volume
Importance?
When you breath out, the volume of air remaining
Importance- ensures the alveolus don’t collapse
Acts as buffer ensuring the gas concentrations don’t change with expiration and inspiration
Vital capacity
Largest possible breath about 4.8L
Total lung capacity-residual
Functional residual capacity
When respiratory muscles are relaxed, the volume of air in lungs at the end of expiration
About 2.4 liters
Tidal Volume
Amount you breath in
About .6 liters at rest
One breath=one tidal volume
Increases with exercise
Gravity affects on FRC
When standing its 1/2 TLC because gracvity is pushing down on abdominal organs
1/3TLC when laying
Pulmonary Function test
The forced vital capacity
Totally inflate lungs up to TLC and the test measures airflow as subject forces air out
Ideally rapid decrease until you reach residual
If there is an obstruction then air moves out ore slowly
Considering measuring FEV1 or FEV3- should be amount residual so if there is a lot left then there is probably obstruction
COnsider measuring the MET
