Lung Structure and Function

Question 1

what is the equation for ventilation?

Answer 1

V=f x TV (ventilation equals frequency of breaths times tidal volume)

Question 2

what is tidal volume and what is its value in the average person?

Answer 2

the volume of air that is inspired or expired in a breath. usually 0.5 L/breath

Question 3

what is the average frequency of breathing? what is the pulmonary ventilation in the average person?

Answer 3

15 breaths/min

7.5 L/min

Question 4

what is another name for ventilation?

Answer 4

minute volume

Question 5

how can ventilation be measured?

Answer 5

using a spiromenter that collects the amount of gas expelled in a minute or adds the amount of gas expelled for each tidal volume.

Question 6

what can ventilation increase to during exercise? what increases to cause this?

Answer 6

120 L/min

both tidal volume and frequency increase

Question 7

what is a spirometer?

Answer 7

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

Question 8

what is the vapor pressure at body temperature when saturated? how does this compare to ambient temperature?

Answer 8

47 mmHg

higher than ambient temperature

Question 9

how is O2 and CO2 consumption and production measured?

Answer 9

reading volume at ATPS and converting it to STPD

Question 10

how is lung volume calculated?

Answer 10

by reading volume at ATPS and converting it to BTPS

Question 11

what is the ideal gas law?

Answer 11

PV=nRT

Question 12

how is the ideal gas law applied to compare lung and spirometer values?

Answer 12

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)

Question 13

what is the volume of air in the lungs compared to the volume collected by a spirometer?

Answer 13

VL= 1.07Vsp

Question 14

how does water vapor pressure relate to temperature?

Answer 14

it is higher at higher temperatures

Question 15

what branches comprise the conductive zone (number and names)?

Answer 15

first 16 branches

trachea, bronchi, bronchiles and terminal bronchiles

Question 16

what branches comprise the respiratory zone (numbers and names)

Answer 16

last 7 branches

respiratory bronchiles, alveolar ducts and alveolar sacs

Question 17

what is another name for the conducting zone and how much air does it contain?

Answer 17

anatomic dead space

150 ml or 1 ml/lb body weight

Question 18

what are the four major components of the respiratory system?

Answer 18

ventilatory apparatus, pulmonary gas exchanger, pulmonary circulatory system and the tissue gas exchanger

Question 19

what is the purpose of the ciliated epithelium in the respiratory tract?

Answer 19

to propel mucus created by goblet cells out of the airway

Question 20

what is the smallest airway with no gas exchange?

Answer 20

terminal bronchioles

Question 21

what are the two types of alveolar cells?

Answer 21

type 1: line alveoli and promote gas exchange

type 2: create surfactant

Question 22

what is surfactant?

Answer 22

a lipoprotein that coats alveoli and lowers surface tension, keeping them open

Question 23

how does the area of the terminal bronchioles, respiratory bronchioles and alveolar ducts and sacs compare?

Answer 23

TB: 80 cm2
RB: 280 cm2
AD&S: 7 x 10^5 cm2

Question 24

how does the change in area of the airway impact the flow of air in those areas?

Answer 24

more cross sectional area causes slower flow

in the alveoli, the velocity is negligible

Question 25

what is the average distance between red blood cells and air in the lungs?

Answer 25

1.5 micron

Question 26

what is the partial pressure of oxygen in the lungs?

Answer 26

it is the same partial pressure of oxygen in the inhaled air that it is has exchanged with

Question 27

how many alveoli does a person have?

Answer 27

300 million

Question 28

what is the dry gas fraction?

Answer 28

moles of a certain gas/ total number of moles of gas in the sample

Question 29

what are the dry gas fractions of N2, O2, CO2 and argon?

Answer 29

0.78, 0.21, 0.0003 and 0.01

Question 30

what does the low concentration of CO2 in the atmosphere indicate?

Answer 30

that an individual does not breath in very much CO2

Question 31

what is true of the partial pressures of gases relative to the total pressure?

Answer 31

all of the partial pressures must equal the total pressure of the sample

Question 32

what is the partial pressure of an individual dry gas?

Answer 32

Pi=niRT/V=FiPt (dry gas fraction times total pressure)

Question 33

what is the equation for partial pressure of a wet gas?

Answer 33

Pi=Fi(Pt-P H2O)

term in parenthesis equals the dry gas pressure

Question 34

what three things are true of the partial pressure of a gas in a solution?

Answer 34

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.

Question 35

what is shunt flow?

Answer 35

bronchial flow that bypasses the gas exchanging portion of the lung and drains into the pulmonary vein

Question 36

what impact does shunt flow have on gas concentrations in the pulmonary vein?

Answer 36

negligible effect on CO2 concentration but dilutes O2 concentration

Question 37

what are alveoli that are ventilated but not perfused? what are alveoli that are perfused but not ventilated?

Answer 37

alveolar dead space

trapped volume