Physiology Flashcards
What are surfactants made of?
Apoprotein + phospholipids + Ca+2
What produces surfactant in bronchioles?
Clara cells
What type of fluid is pleural fluid?
Mucoid (interstitial + protein)
What is the main muscle of forceful inspiration?
Sternocleidomastoid
What is the main muscle of quiet inspiration?
Diaphragm
Muscles of forceful expiration?
Internal intercostals + abdomen
How to measure pressure in CMs of water?
mmHg x 1.37
What is intrathoracic pressure?
-4
When is transmural pressure highest?
End of inspiration
What are capacities used for?
Diagnosis restrictive and obstructive diseases
How much is tidal volume?
500ml
Which volume/capacity can’t be measured by spirometer?
Residual volume and thus FRC
How much is inspiratory reserve volume?
3000ml
How much is expiratory reserve volume?
1000ml
How much is residual volume?
1200ml
How much is functional residual capacity?
2200ml
How is much is vital capacity?
4500ml
How much is total lung capacity?
5700ml
What is FEV1?
Forced expiratory volume in 1 second which should be 80% of forced vital capacity
What does low FVC indicate?
Restrictive lung disease
What does low FEV1 indicate?
Obstructive lung disease
Why does exhalation take longer?
Passive + more airway resistance
What is dalton’s law?
Total pressure exerted by a mixture equals the sum of all partial pressures
Name the 4 factors in fick’s law
1) Membrane thickness
2) Membrane surface area
3) Partial pressure gradient
4) diffusion coefficient of gas
5) Chemical nature of membrane (not applicable here)
What is the average thickness of respiratory membrane?
0.6 um
Why does CO2 have a higher diffusion coefficient when it’s bigger?
It’s more soluble
Rank O2,N2,CO2 in order of diffusion coefficient
CO2>O2>N2
What diseases affect respiratory membrane surface area?
Emphysema & elastase production inducers (smoking & cancer)
What part of fick’s law could edema affect?
Thickness of membrane
What is Henry’s law?
The higher the partial pressure the higher the solubility of a gas
CO2 diffuses ….X times more than O2
20
How much are PaO2 & PaCO2?
PaO2= 100mmHg
PaCO2= 40mmHg
How much are PvO2 & PvCO2?
PvO2= 40mmHg
PvCO2= 46mmHg
Partial pressure of arterial blood in the aorta?
95mmHg
What is the diffusion capacity of O2 and CO2 in a resting state?
21 & 420 ml/min/mmHg respectively
What is the diffusion capacity of O2 and CO2 during exercise?
65 & 1250 ml/min/mmHg respectively
How much does pressure change during breathing?
+- 11mmHg
What is the average V/Q ratio in a healthy lung?
0.8
What is the average perfusion of the lung?
5.5L/min
What is V/Q in upper lobe?
3
What is V/Q in the lower lobe?
0.6
What are the 2 factors affecting PO2 in tissue?
Blood flow & oxygen consumption
How much of oxygen is dissolved in plasma?
1.5-3%
What is the concentration of Hb & O2 in saturated blood?
15 grams/dl = 20 ml/dl
At what PO2 does O2 saturation plateau?
60 mmHg
How much is utilization coefficient?
25-30%
What is the effect of temperature on o2 disassociation curve?
Shift to the right
What is the effect of BPG on o2 disassociation curve?
Shift to the right
At what carbon monoxide partial pressure is Hb saturation almost 100%?
0.6 mmHg
What is the percentage of CO2 dissolved in the blood?
7%
What is the most common form to transport CO2 in?
HCO3-
What is the saturation of Hb with CO2 usually?
50%
Where does CO2 bind to in Hb?
Globin amine radicals
What is the saturation of Hb by O2 in venous blood?
75%
