Chapter 17 - Mechanics of Breathing

Question 1

3 functions of the upper resp system

Answer 1

filter, warm, and humidify inhaled air

Question 2

type I alveolar cells

Answer 2

thin-walled cells that make up most of alveoli. function: gas exchange

Question 3

type II alveolar cells

Answer 3

produce surfactant

Question 4

average pulmonary arterial pressure

Answer 4

25/8 mm Hg

Question 5

Dalton’s law

Answer 5

states that the total pressure of a mixture of gases is the sum of the pressures of the individual gases in the mixture. partial pressure is the pressure contributed by a single gas in a mixture

Question 6

Boyle’s law

Answer 6

states that as the volume available to a gas increases, the gas pressure decreases. the body creates pressure gradients by changing thoracic volume. (P1V1 = P2V2)

Question 7

tidal volume

Answer 7

the amount of air taken in during a single normal inspiration

Question 8

vital capacity

Answer 8

tidal volume plus expiratory and inspiratory reserve columes

Question 9

residual volume

Answer 9

air volume in the lungs at the end of maximal expiration

Question 10

vital capacity

Answer 10

the sum of the inspiratory reserve volume, expiratory reserve volume, and tidal volume

Question 11

during inspiration, alveolar pressure ___

Answer 11

decreases.

Question 12

expiration is usually passive, resulting from

Answer 12

elastic recoil of the lungs

Question 13

intrapleural pressure are subatomspheric b/c…

Answer 13

the pleural cavity is a sealed compartment

Question 14

compliance

Answer 14

a measure of the ease w/ which the chest wall and lungs expand. loss of compliance increases the work of breathing

Question 15

elastance

Answer 15

the ability of a lung to resist stretching or to return to its unstretched state

Question 16

surfactant

Answer 16

decreases surface tension in the fluid lining the alveoli. reduced surface tension prevents smaller alveoli from collapsing and also makes it easier to inflate the lungs

Question 17

total pulmonary ventilation =

Answer 17

ventilation rate x tidal volume

Question 18

alveolar ventilation =

Answer 18

the volume of fresh air that reaches the alveoli each minute.

ventilation rate x (tidal volume - dead space volume)

Question 19

hyperventilation ___ alveolar PO2 and ___ alveolar PCO2

Answer 19

increases; decreases. (hypoventilation has the opposite effect)

Question 20

increases CO2 in expired air ___ bronchioles

Answer 20

dilates

Question 21

4 functions of the respiratory system

Answer 21

gas exchange, vocalization, pH regulation, protection

Question 22

saline secretion by airway epithelial cells

Answer 22

1.) NKCC brings Cl- into epithelial cell from ECF. 2.) Apical anion channels, including CFTR, allow Cl- to enter the lumen. 3.) Na+ goes from ECF to lumen by the paracellular pathway, drawn by the electrochemical gradient. 4.) NaCl movement from ECF to lumen creates a concentration so water follows into the lumen.