Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
Abbreviations- P, Q, V, Vdot, F |
P- Partial pressure of gas; Q- blood flow; V- Volume of gas; Vdot- airflow/volume per minute; F- fraction concentration of gas |
|
|
Modifies- A, a, v, E, I |
A- Alveolar gas; a- arterial gas; v- venous blood; E- expired gas; I- inspired gas |
|
|
Diaphragm |
Inspiration; phrenic N.; contract = flattens; increases colume of thorax |
|
|
External intercostal M. |
Inspiration; contract= raise ribs; increases anteroposterior diameter of thorax (bucket handle motion) |
|
|
Pros/ cons respiratory skeletal muscles |
TBD |
|
|
Events in Inspiration |
1. contraction of inspiratory M.s; increases thoracic volume 2. increase in thoracic volume = decrease intrapleural pressure (-8 cm H2O) 3. lungs expand as thoracic expands 4. lungs increase = alveolar pressure decreases (rest 0 cm H2O, normal inspiration -1 cm H2O) 5. negative pressure causes airflow in |
|
|
Intrapleural pressure |
fluid between lung and pleura is always pushing the two walls away from each other below atmospheric pressure (normally -5 cm H2O) |
|
|
What is the used atmospheric pressure if the barometric pressure is 760 mm Hg |
0 cm H20 |
|
|
VT |
tidal volume; air inhaled in given breath; typical breath (-500 mL) |
|
|
Intrapleural pressure lowest point |
end of inspiration; normal breath (-8 cm H2O) |
|
|
Expiratory muscles |
Abdominal M.s- displace diaphragm upwards Internal intercostal M.s- decrease anterior-posterior diameter of thorax |
|
|
Regular expiration needs: |
expiration is passive; lungs want to be small; like a balloon |
|
|
Events in Expiration |
1. Inspiratory M.s relax, causes volume of thorax decrease 2. decreasing volume = intrapleural pressure return to starting (-5 cm H2O) 3. decrease volume = alveolar pressure peaks at (+1 cm H2O)(mid expiration) returns to (0 cm H2O) 4. Airflow out |
|
|
Respiratory cycle magnitudes |
Volume change (liters)- 0 .5 0 Alveolar pressure (cm H2O)- 0 (-1) 0 (1) 0 Intrapleural pressure (cm H2O)- -5 -8 -5 Air Flow (L/sec)- 0 (-1) 0 (1) 0 |
|
|
Why does the intrapleural pressure not return to resting until after expiration but alveolar pressure does? |
The added molecules of air that enter the alveolus compensates for the increased volume while no molecules are added to the intrapleural pressure and therefore the increase volume is never compensated for |
|
|
V(dot) (ex.14, 500) |
Minute ventilation = VT x frequency/min ex. 500 ml/breath x 14 breaths/min = 7000 ml/min or 7 L/min |
|
|
VDS (ex. 150) |
Anatomic dead space the first part of the airway where we can't exchange O2 but we still need to get air into them ex. 150 lb person = 150 mL dead space |
|
|
Valv (ex. 500 150) |
Alveolar venilation= VT- VDS amount of air that gets to the alveoli ex. 500 mL/breath - 150 mL dead space = 350 mL got to alveoli |
|
|
V(dot)A (ex. 350, 12) |
Minute Alveolar Ventilation= Valv x f air to alveoli every minute ex. 350 mL air to alveoli x 12 breaths/min = 4200 mL/min or 4.2 L/min |
