phys 3

Question 1

anatomical dead space

Answer 1

inspired air which remains in the airways where it is not available for gas exchange

Question 2

pulmonary ventilation(L) =

Answer 2

“tidal volume (L/breath) x Respiratory Rate (breath/min)

“

Question 3

Alveolar Ventilation is less than pulmonary ventilation because of

Answer 3

the presence of anatomical dead space

Question 4

alveolar ventilation =

Answer 4

(tidal volume – dead space volume) x Respiratory Rate

Question 5

pulmonary ventilation is the

Answer 5

volume of air breathed in and out per minute

Question 6

Alveolar Ventilation is

Answer 6

the volume of air exchanged between the atmosphere and alveoli per minute

Question 7

why is alveolar ventilation more important than pulmonary ventilation

Answer 7

alveolar ventilation represents new air available for gas exchange with blood

Question 8

what can be done to increase pulmonary ventilation

Answer 8

“the depth of breathing(tidal volume) and

rate of breathing (RR) increase”

Question 9

the transfer of gases between the body and atmosphere depends upon

Answer 9

“ventilation

perfusion”

Question 10

ventilation is the rate at which

Answer 10

gas is passing through the lungs

Question 11

blood flow and ventilation vary from ____ to ____ of the lung

Answer 11

“bottom, top

they are both higher at the bottom”

Question 12

why are some ventilated alveoli considered as alveolar dead space

Answer 12

they are not adequately perfused with blood

Question 13

physiological dead space =

Answer 13

the anatomical dead space + the alveolar dead space

Question 14

Local controls act on the smooth muscles of ____ and ____ to match ____ to ____

Answer 14

airways, arterioles, airflow, blood flow

Question 15

Increase in alveolar O2 concentration as a result of increased ventilation causes

Answer 15

pulmonary vasodilation which increases blood flow to match larger airflow

Question 16

what happens in areas in which perfusion is greater than ventilation

Answer 16

“CO2 increases in the area
O2 decreases in the area

dilation of local airways
constriction of local blood vessels

airflow increases
blood flow decreases”

Question 17

effect of decreased O2 on pulmonary arterioles and systemic arterioles, respectively

Answer 17

vasoconstiction, vasodilation

Question 18

effect of increased O2 on pulmonary arterioles and systemic arterioles, respectively

Answer 18

vasodilation, vasoconstriction

Question 19

factors that influence the rate of gas exchange across alveolar membrane

Answer 19

“partial pressure gradient of O2 and CO2
diffusion coefficient for O2 and CO2
surface area of alveolar membrane
thickness of alveolar membrane”

Question 20

partial pressure of a gas determines

Answer 20

the pressure gradient for that gas

Question 21

The partial pressure of gas (1) in a mixture of gases that don’t react with each other is

Answer 21

The pressure that gas (1) would exert if it occupied the total volume for the mixture in the absence of other components

Question 22

Ptotal =

Answer 22

P1 + P2 +…+ Pn

Question 23

partial pressure of a gas is

Answer 23

The pressure that one gas in a mixture of gases would exert if it were the only gas present in the whole volume occupied by the mixture at a given temperature.

Question 24

value of the total atmospheric pressure

Answer 24

101Kpa

Question 25

value of water vapour pressure in the lungs

Answer 25

about 47mmHg

Question 26

why is there a water vapour pressure

Answer 26

air in the respiratory tract is saturated with water

Question 27

alveolar gas equation

Answer 27

PAO2 = PiO2 - [PaCO2/0.8]

Question 28

“Respiratory Exchange Ratio (RER)

”

Answer 28

“RER is the ratio of CO2 produced/O2 consumed)

normal value Is 0.8 for someone eating a mixed diet.”

Question 29

where do gases move due to the partial pressure gradient

Answer 29

from higher to lower partial pressures

Question 30

diffusion coefficient

Answer 30

the solubility of gas in membranes

Question 31

what does a big gradient between PAO2 and PaO2 indicate

Answer 31

problems with gas exchange in the lungs or a right to left shunt in the heart

Question 32

ficks law of diffusion

Answer 32

"The amount of gas  that moves 
across a sheet of tissue in unit 
time is proportional to the area of 
the sheet but inversely proportional
 to its thickness"

Question 33

features of the lungs that help facilitate effective gas exchange

Answer 33

“large surface area

thin membranes”