Lung Structure and Function Flashcards
1
Q
pulmonary disease
A
- COPD is 4th leading cause of death in the US
- pneumonia and flu 7th
2
Q
ventilation
A
- flow of air into and out of the lungs
- Vdot=f x TV
- f is frequency of breathing (breaths/min)
- TV is tidal volume (L/breath)
- delivers oxygen in from atm and tissues
- use oxygen to produce ATP
- need continuous supply
3
Q
spirometer
A
- measures ventilation
- typical is 7.5 L/min
- can rise over 15X to as much as 120 L/min
- collecting expired gas for 1 min or measuring tidal volume for 1 min
- spirometer has floating inverted drum and is attached to a pen
- measures volume and volume vs time gives flow
4
Q
ATPS
A
- ambient temp and pressure, saturated
- 25 C, 760 mm Hg, 24 mm Hg
5
Q
BTPS
A
- body temp and pressure, saturated
- 37 C, 760 mm Hg, 47 mm Hg
6
Q
STPD
A
- standard temp and pressure, dry
- 0 C, 760 mm Hg, 0 mmHg
- convert from ATPS to STPD for o2 consumption and Co2 production rates
- convert from ATPS to BTPS for lung volumes
7
Q
ideal gas law
A
PV= nRT
8
Q
boyle’s law
A
P= k/V
9
Q
charles’s law
A
V=kT
10
Q
gay-Lussac’s law
A
P=kT
11
Q
gas volume corrections
A
- ideal gas law is for dry gas
- PV=nRT
- PV/T=nR=constant
- so PLVL/TL= PspVsp/Tsp
- must correct pressures for water vapor pressure (24 for spirometer, 47 for lungs)
- can find ratio of volumes
- V in lungs is 1.07XVsp- 7% increase
12
Q
water vapor pressure
A
- function of temperature, constant at a given temo
- body at 37 is 47 mm Hg
13
Q
conductive zone of lungs
A
- first 16 branches (4 bifurcations)
- trachea
- bronchi
- bronchioles
- terminal bronchioles
- no gas exchange
- anatomic dead space (150 ml, 1 ml/lb of body weight)
- ciliated surface propels mucous secreted by goblet cells
14
Q
respiratory zone
A
- last 7 branches
- respiratory bronchioles
- alveolar ducts
- alveolar sacs
- 23 branches lead to 300 million alveoli, each of which is 250 microns in diameter and covered with about 1000 pulmonary caps
15
Q
structures and functions within the respiratory system
A
- ventilatory apparatus-conductive zone
- pulmonary gas exchanger-alveoli
- pulmonary circulatory system
- tissue gas exchanger
16
Q
respiratory zone 2
A
- gas exchange
- type I alveolar cells line alveoli
- type II secrete surfactant, lipoprotein containing DPPC
17
Q
surfactant
A
- from type II
- lipoprotein with DPPC
- coats alveoli
- lowers their surface tension, easier to inhale
- increases mechanical stability of lung
18
Q
alveolar cross sectional area
A
- trachea is 2 cm2
- alveoli is 70 m2
- area increases and velocity decreases, Q remains same
- diffusion rather than flow carries gas
- permits equilibrium of alveolar gas with blood
19
Q
movement of o2 from alveoli
A
- crosses surfactant covered alveolar epithelium
- alveolar interstitial space
- cap endo
- plasma
- RBC PM
- combines with hemoglobin
20
Q
composition of air
A
- 78% nitrogen
- 21% oxygen
- 0.03% carbon dioxide
- 1% argon
21
Q
gas fraction
A
- Fi=ni/nt
- Fn=nN/nt
- moles of nitrogen over total moles
22
Q
partial pressure
A
- from ideal gas law for dry gases
- Pt=nRT/V
- Pi=niRT/V
- Pt=sumPi
- Partial pressure for dry gas- FiPt (fraction times pressure- 0.21 fraction oxygen times total pressure)
- for wet gas
- Pi=F(Pt-PH2O) (Pwater is 47)
23
Q
solubility
A
- henry’s law
- [cg]=aPi
- dissolved gases don’t contribute to blood volume or blood pressure
- partial pressure of a gas in solution equals the partial pressure of the gas with which the solution has equilibrated (po2 in alveoli is 100, therefore it is 100 in blood)
- partial pressure of a gas in solution refers only to dissolved gas
24
Q
summaries
A
-see picture and draw out!
