Lung Structure and Function Flashcards
what is the equation for ventilation?
V=f x TV (ventilation equals frequency of breaths times tidal volume)
what is tidal volume and what is its value in the average person?
the volume of air that is inspired or expired in a breath. usually 0.5 L/breath
what is the average frequency of breathing? what is the pulmonary ventilation in the average person?
15 breaths/min
7.5 L/min
what is another name for ventilation?
minute volume
how can ventilation be measured?
using a spiromenter that collects the amount of gas expelled in a minute or adds the amount of gas expelled for each tidal volume.
what can ventilation increase to during exercise? what increases to cause this?
120 L/min
both tidal volume and frequency increase
what is a spirometer?
a floating inverted drum that moves up and down as air is inhaled or exhaled. this is attached to a pen that draws a graph of volume vs time
what is the vapor pressure at body temperature when saturated? how does this compare to ambient temperature?
47 mmHg
higher than ambient temperature
how is O2 and CO2 consumption and production measured?
reading volume at ATPS and converting it to STPD
how is lung volume calculated?
by reading volume at ATPS and converting it to BTPS
what is the ideal gas law?
PV=nRT
how is the ideal gas law applied to compare lung and spirometer values?
since n and R are the same in both equations, you can say that P1V1/T1=P2V2/T2 (1 is the spirometer and 2 is the lung)
what is the volume of air in the lungs compared to the volume collected by a spirometer?
VL= 1.07Vsp
how does water vapor pressure relate to temperature?
it is higher at higher temperatures
what branches comprise the conductive zone (number and names)?
first 16 branches
trachea, bronchi, bronchiles and terminal bronchiles
what branches comprise the respiratory zone (numbers and names)
last 7 branches
respiratory bronchiles, alveolar ducts and alveolar sacs
what is another name for the conducting zone and how much air does it contain?
anatomic dead space
150 ml or 1 ml/lb body weight
what are the four major components of the respiratory system?
ventilatory apparatus, pulmonary gas exchanger, pulmonary circulatory system and the tissue gas exchanger
what is the purpose of the ciliated epithelium in the respiratory tract?
to propel mucus created by goblet cells out of the airway
what is the smallest airway with no gas exchange?
terminal bronchioles
what are the two types of alveolar cells?
type 1: line alveoli and promote gas exchange
type 2: create surfactant
what is surfactant?
a lipoprotein that coats alveoli and lowers surface tension, keeping them open
how does the area of the terminal bronchioles, respiratory bronchioles and alveolar ducts and sacs compare?
TB: 80 cm2
RB: 280 cm2
AD&S: 7 x 10^5 cm2
how does the change in area of the airway impact the flow of air in those areas?
more cross sectional area causes slower flow
in the alveoli, the velocity is negligible
what is the average distance between red blood cells and air in the lungs?
1.5 micron
what is the partial pressure of oxygen in the lungs?
it is the same partial pressure of oxygen in the inhaled air that it is has exchanged with
how many alveoli does a person have?
300 million
what is the dry gas fraction?
moles of a certain gas/ total number of moles of gas in the sample
what are the dry gas fractions of N2, O2, CO2 and argon?
0.78, 0.21, 0.0003 and 0.01
what does the low concentration of CO2 in the atmosphere indicate?
that an individual does not breath in very much CO2
what is true of the partial pressures of gases relative to the total pressure?
all of the partial pressures must equal the total pressure of the sample
what is the partial pressure of an individual dry gas?
Pi=niRT/V=FiPt (dry gas fraction times total pressure)
what is the equation for partial pressure of a wet gas?
Pi=Fi(Pt-P H2O)
term in parenthesis equals the dry gas pressure
what three things are true of the partial pressure of a gas in a solution?
1 they do not contribute to blood volume or blood pressure
2 partial pressure of a gas equals the partial pressure with which the solution has equilibrated
3 partial pressure of a gas in solution refers only to dissolved gas.
what is shunt flow?
bronchial flow that bypasses the gas exchanging portion of the lung and drains into the pulmonary vein
what impact does shunt flow have on gas concentrations in the pulmonary vein?
negligible effect on CO2 concentration but dilutes O2 concentration
what are alveoli that are ventilated but not perfused? what are alveoli that are perfused but not ventilated?
alveolar dead space
trapped volume
