Chapter 14: Spirometry and Respiratory Function

Question 1

Tidal Volume (TV)

Answer 1

500 mL

Amount of air exchanged in a ‘quiet inspiration’

Question 2

Inspiratory Reserve Volume (IRV)

Answer 2

3000 ml

Amount of air inspired after a quiet inspiration

Question 3

Expiratory Reserve Volume (ERV)

Answer 3

1100 ml

Amount of air expired after a quiet expiration

Question 4

Residual Volume (RV)

Answer 4

1200 ml

Air remaining in lungs after maximum expiration

Question 5

Vital Capacity (VC)

Answer 5

4800 mL

TV + IRV + ERV

Question 6

Inspiratory Capacity (IC)

Answer 6

3600 mL

TV + IRV

Question 7

Functional Residual Capacity (FRC)

Answer 7

2400 mL

ERV + RV

Question 8

Total Lung Capacity (TLC)

Answer 8

6000 mL

All volumes

Question 9

Forced Expiratory Volume

Answer 9

COPD, Such as Asthma show reduced FEV, it is more difficult to air to flow

Question 10

Boyle’s Law

Answer 10

↑Pgas=↓Vgas or ↓Pgas=↑Vgas

Lungs can change Volume of gas; therefore can change Pressure of gas.

Question 11

Charles’s Law

Answer 11

↓Vgas =↓Togas or ↑Vgas=↑Togas

Lungs raise Temperature of gas which increases Volume of gas.

Question 12

Dalton’s Law

Answer 12

Gas pressure (atmosphere) is the summation of the partial pressures of the different gases in it, such as PO2 + PCO2 + N2, etc.

Question 13

Physical Laws

Answer 13

Air moves from high pressure P1 to low pressure P2

Question 14

Diaphragm Contracting

Answer 14

Atmospheric Pressure at Sea Level: 760 mmHg
Intrapulmonary (Alveolar) Pressure: 757 mmHg
Intrapleural Pressure: 754 mmHg (-6 mmHg)

Question 15

Diaphragm Relaxing

Answer 15

Atmospheric Pressure at Sea Level: 760 mmHg
Intrapulmonary (Alveolar) Pressure: 763 mmHg
Intrapleural Pressure: 756 mmHg (-4 mmHg)

Question 16

Resistance and Airflow

Answer 16

F=ΔP/R, where F=flow, P=pressure, R=resistance

Air flow (F) is decreased by increased resistance (R):
Decreased bronchi radius is called broncheoconstriction (allergies, cold air, anaphylactic shock, inflammation, or mucous accumulation)

increased bronchi radius is called broncheodilation (Sympathetic nerves: epinephrine, norepinephrine)

Question 17

Factors that Influence Respiratory Rate

Answer 17

Regulated by a central pattern generator in medulla

Normal ‘quiet’ breathing (when at rest but awake) is 500 ml X 12 breaths per minute = 6000 ml of air per minute

Question 18

Hyperventilation

Answer 18

means increased respiratory rate – caused by:
Sympathetic stimulation (epinephrine-bronchiodilation), blood acidosis, hypercapnia (high CO2 in blood plasma), low [O2] in blood, emotional distress, pain.

results in ↑CO2 expelled from body -> ↓Blood [CO2] (hypocapnia) -> ↓Blood [H+] (which is alkalosis),

Local Correction/Compensation: ↑vasoconstriction brain blood vessels which ↓Blood Flow to brain ↓brain perfusion dizziness fainting.

Systemic Correction: Breathing into a paper bag

Question 19

Hypoventilation

Answer 19

means decreased respiratory rate – caused by:
Inhibition of reticular formation (sleep), obstruction, holding breath, hypocapenia (low CO2 in blood plasma), emotional distress, pain.

results in ↓CO2 expelled from body -> ↑Blood [CO2] (hypercapnia) -> ↑ Blood [H+] (blood acidosis), also results in ↓[O2] blood -> ↓tissue perfusion -> ↓aerobic cellular respiration -> ↓ATP

‘Local’ compensation/correction: blood vessels respond by ↑vasodilation (due to epinephrine) to ↑tissue perfusion,

Systemic Correction/compensation: brainstem ‘forces’ ↑sympathetic activity

Question 20

Cellular respiration

Answer 20

during aerobic respiration, mitochondria use glucose (6-carbon sugar) in cyclical reactions to produce ATP and give off CO2 as waste, O2 is used as the final electron acceptor

Carbonic anhydrase (CAH) catalyzes:
CO2   +   H2O   H2CO3   HCO3- +   	H+

Question 21

Increased [CO2] and [H+] are detected in blood and cerebrospinal fluid by

Answer 21

chemoreceptors

Question 22

Inspiratory neurons

Answer 22

(medulla) fires during normal, ‘quite’, inspiration, innervates diaphragm

Question 23

Expiratory neurons

Answer 23

fire ONLY during forced expiration. innervates intercostal and abdominal muscles.

Question 24

Law of Laplace

Answer 24

pressure on alveolar wall is proportional to its surface tension, and inversely proportional to its radius.

alveolus will tend to collapse with ↑surface tension (elasticity/fluid) or ↓radius, because alveolar walls are elastic and hydrogen bonding between water molecules on the outer wall of the alveoli pushes it inward during expiration (small radius)

Question 25

Surfactant

Answer 25

secreted by Type II alveolar cells, reduces surface tension produced by water molecules on surrounding alveoli.

Question 26

Henry’s Law

Answer 26

Amount of gas that dissolves in water depends on its solubility and partial pressure in air (assume constant temperature).

Question 27

Composition of Atmospheric Air

Answer 27

N2=78.6%, O2=21%, CO2=0.04%, H20=0.5%