Pulmonary Flashcards
Anatomical Dead Space (and the generations which make it up)
Conducting airways.
Generations 1-16
Vd
Volume of anatomical dead space
150mL
Transition zone
transitioning from conducting to respiratory
generations 17-19
Volume of lung which participates in gas exchange
2500mL
What type of cells produce surfactant?
Alveolar type II
Important Connections for Interdependence of bronchioles
Channels of Martin (interbronchial)
Channel of Lambert (bronchiole-alveoli)
Pores of Kohn (interalveolar –> collateral ventilation)
Vt
Tidal Volume
Change in volume during normal breathing
500mL
IRV
Inspiratory Reserve Volume
Volume which can be inhaled on top of Vt
3000mL
ERV
Expiratory Reserve Volume
Volume which can be exhaled beyond Vt
1200mL
RV
Residual Volume
Volume that remains in lung even after forced expiration
1200mL
IC
Inspiratory Capacity
Total you can inspire
IC= IRV +Vt= 3500mL
FRC
Functional Residual Capacity
Volume of air in lungs when all respiratory muscles are relaxed.
FRC=ERV + RV =2400mL
VC
Vital Capacity
Max air which can be moved from deep expiration to deep inspiration.
VC= IRV + Vt +ERV= 4700mL
TLC
Tung Lung Capacity
Total volume of air held by the lungs
TLC= IRV + Vt + ERV + RV = 5900mL
What method can measure FRC?
Helium dilution
FEV1/FVC
Amount of air you can push out in 1 sec/ total amount of air you can push out
should 75-80%
Volume of respiratory region (non-dead space)
2.5-3L
Methods which can measure RV
- Helium dilution
- Body plethysmography
3 flow types and the generations they’re associated with.
Turbulent: Generations 0-9
Laminar: Generations 10-16
Diffusive: Generations 17-23 (occurs continuously and independent of respiratory cycle)
Elastic work is proportional to…
Non-elastic work is proportional to…
Elastic –> Tidal Volume
Non-elastic (restriction-based) –> Frequency of Breathing
4 Causes for Hypoxemia
(1) Hypoventilation (no change in AaDO2)
(2) Diffusion Limitation (thickness, reduced area, etc.)
(3) Shunt (no change from increased O2)
(4) V/Q inequality
Hypoxia vs Hypoxemia
- Hypoxia- deprivation of the body or specific organs due to mismatch in oxygen supply and tissue demands
- Hypoxemia- when oxygen concentration in arterial blood is too low
◦PaO2 less than 80 mmHg
◦Signs visible less than 60 mmHg
Diving Response
- Initial Hypertension
- Vasoconstriction
- Bradycardia (vagally induced)
- Splenic contraction
Hypoxic Loss of Conciousness
20-25mmHg
Calculating Physiological Dead Space
Vd/Vt = (PaCO2- PeCO2)/PaCO2
(what could be expired - what is expired)/what could expired
Normal ratio: .2-.35
Vt: in place to normalize physiological dead space for a given tidal volume
Fick’s Law
The amount of gas transferred is proportional to the area (A), and difference in partial pressure
Graham’s Law
Describes the factors which aid diffusion; tells us CO2 diffuses 22x better than O2
Hypoxic Vasoconstriction
When a part of the lung has low ALVEOLAR PO2, blood is shifted from hypoxic areas to well-perfused areas (so as to not waste blood where it won’t be ventilated)
Causes of AaDO2
- V/Q inequality
- Anatomic shunt
- Thebesian vessels
- Bronchial/Pulmonary veins
Henry’s Law
The concentration of a solute gas in a solution is directly proportional to partial pressure of that gas above the solution.
C= kH (P)= concentration is solution= dissolving constant (pressure)
Function of CO
In the presence of small amounts of CO, affinity for O2 is greatly enhanced and unloading is prevented (hence suffocation).
Chloride Shift
When intracellular [H+] and [HCO3-] increase in erythrocytes, HCO3- diffuses out and Cl- in, to maintain electrical neutrality
Haldane effect
The presence of O2 decreases the affinity of hemoglobin for CO2 and assists in the unloading of CO2 from the blood to the alveolar spaces
4 Major Types of Tissue Hypoxia
HYPOXIC HYPOXIA (decreased PaO2 leading to leading to insufficient O2 delivery to tissues)
CIRCULATORY HYPOXIA (reduced blood flow to tissues)
ANEMIC HYPOXIA (inability to carry sufficient oxygen)
HISTOTOXIC HYPOXIA (inability to utilize oxygen– poisoning)
