respiration course pack slide 101-145 Flashcards
What does the chest wall include?
Are the lungs attached to chest wall?
What does pulling on ribcage cause?
-rib cage, diaphragm and abodominal wall
-they are not directyl attached
-causes pleural pressure to get more negative
How are the visceral and parietal pleura coupled together?
what is the pressure at rest in pleural space?
-they are coupled together by a thin layer of liquid that fills the intraplueral space
-pressure is negative
What happens during a pneumothorax?
-lungs collapse and the chest springs outwards, causing the pressure to be 0 in pleural space
How is lung volume measured, how is the respiratory system measured?
-lung volume measured by spirometer
-respiratory system measured by manometer
How is the recoil pressure defined?
How can Ppl be measured?
What does decresing pleural pressure do?
-it is the differnce between Ppl abd the body surface
Pw=Ppl-Pbs (trans chest wall=pleural pressure-body surface
pressure)
-Ppl can be measured using a felxible baloon in esophagus
-it pulls the lungs open
What is compliance of the lungs?
What increases as the volume inside lungs increases?
What is the lung compliance formula (Cl)?
Compliance of lungs is inverse of what?
it is the ease to which the structure can be distended
-pressure needed to maintain a given volume of gas increases as the volume increases
Cl=V/(Palv-Ppl)
-inverse of elastance El=1/Cl
What does emphysema and fibrosis cause in terms of lung capacity?
-emphysema- there is no recoil in lungs so expiration is harder since destruction of alveolar walls, so alveoli will inflate very easily
-fibrosis-lungs are hard to inflate since alveoli is stiff
When is it harder for lungs to stretch?
What does the chest want to do at lower volume vs higher volume?
-harder for lungs to stretch at higher volumes of air
-at lower volume wans to spring out (when at -5cm H2O)
-at higher value wants to collapse (when =5 cm h2O)
What added together gives you TLC (total lung capacity)?
What is Prs at FRC?
At FRC what volume are the chest and lungs at?
-adding the chest wall and ling pressure gives you TLC pressure
-At FRC the Prs is zero since the system is at rest
_at FRC the lungs are above resting volume, and the chest is below resting volume
What happens to lungs and chest wall during pneumothorax?
-lungs collapse to its resting position below RV (residual volume)
-chest wall expands towards resting position at about 60% TLC
What are the lungs at during rest?
What happens during inspiration?
-at rest the lungs are at FRC and Ppl is negative due to opposite force acting on the lungs + chest wall
-during inspiration the diaphragm contracts and chest wall is pulled open, creating more negatice Ppl causing lungs to exapnd
What is the flow during inspiration vs expiration?
-inspiration flow is negative since Palv<Patm (airflow goes down pressure gradient, outside to inside)
-expiration flow is positive since Palv>Patm (airflow goes from inside to outside)
When does inspiration stop?
What does Ppl depends on during inspiration and expiration?
-stops when Palv=Patm since the lungs are filled up with air and the pressure gradient and air flow decreases
-depends on diaphragm contraction and airway resistance
What does asthma cause in terms of resistance and what can be given to help that?
-airway resistance can become very hih making breathing difficult
-bronchodialators can be given to decrease airway resistance
How does compression of airways differ from inhalation slope?
-inhalation slope depends on the effort put in , while the descending expiration portion is independent of effort
What happens to the pressures during forced expiration?
-intrapleural and alveolar pressure increase, but due to pressure drop along airways as flow begins there is a point at which there is a positive pressure tending to close the airways
What is an example of an obstructive disease vs a restrictive lung disease?
-obstructive disease would be emphysema where you have a very low flow, since the alveoli are very compliant, very high TLC and large RV
-restrictive disease would be pulmonary fibrosis where the flow rate and maximum volume exhaled are reduced, low TLC
What are the events that occur in inspiration?
DCITLAF
D-Diaphragm and intercostal muscles contract
C-thoracic cage expands
I-intrapleural pressure becomes more negative
T-transpulmnary pressure increases (pulls lungs open)
L-lungs expand
A-Alveolar pressure becomes more subatmospheric
F-air flow into alveoli
What are the events for expiration?
D-diaphragm and intercostal muscles stop contracting
W-chest wall moves inward
I-intrapleural pressure goes back towards preinspiratory value
T-transpulmonary pressure goes back towards preinspiratory value
R-lung recoil towards preinspiratory value
L-air in lung is compressed
A-alveolar pressure is greater than atm pressure
F-Flow out of lung
What happens when excercise starts?
What happens to the inspiratory and expiratory times during progressive excercise?
-tidal volume (VT) and breathing frequency (f) increase proportionally
-then Vt plateaus, so high ventilatory rates are due to incremental increases in f
-they decrease during progressive excercise but expiratory times fall relatively more than inspiratory times
What happens when you decrease expiration more than inspiration?
-flow increases since you have less time to expire
How does Ve increase in untrained vs trained subjects?
What does endurance training help with>
-Ve increases linearly with VO2 up to 50-65% of VO2 max, after Ve increases faster than change in VO2
-endurance training helps to delay the ventilatory inflection point (Tvent)
How many times does Ve increase during excercise vs rest?
How many times does cardiac output increase?
What is the VE/Q at rest?
-35x during excercise, from 5L/min to 190L/min
-Co increases 5-6x during excercise, from 5L/min to 25-30L/min
-Ve/Q is around 1 at rest, and can increase during excercise
What is the average blood volume?
What is the alveolar surface area?
How much percent of blood is in the pulmonary system?
-5L of blood
-50m^2 (1/2 tennis court size)
-4% of this 5L is in the pulmonary system at any time during maximal exercise
During excercise what happens to pH?
what does this decrrease and do chemoreceptor play a role during excercise/
-pH increases in response to medullary ECF
-this decrease the ventilatory response
-role of central chemoreceptor is important at rest but not as much in excercise
Wht are peripheral chemoreceptors sensitive to?
How does PaO2 change during excercise vs PaCO2?
What activates the peripheral chemoreceptor during excercise?
-changes in PO2, and increases in PCO2 and decreased pH
-PaO2 remains constant during excercise
-PaCO2 often decreases during excercise so neither of these cause stimulation of peripheral chemoreceptor?
-pH does decrease and PaO2 fluctuates a bit with arterial pulse waves which can cause sensitivity to chemorecptors for CO2 and H+
What produces an increase in Ve during excercise?
What is responsible for main ventilatory response during excercise?
-pulmonary mechanoreceptors, muscle spindles, golgi tendon, and skeletal joint receptors play a bit of a role in increase of Ve
-humoral control (brain tells you to increase ventilation
