Unit 3 Day 2 (Wed 4/22)

Question 1

Minute Ventilation

Answer 1

• volume of air flow through the lung in one minute = 6 L

- minute ventilation = tidal volume x breathing rate

Question 2

Alveolar Ventilation

Answer 2

• V(A)

- volume of air flow in alveolar space in one minute (4.2 L)

Question 3

Factors That Influence Lung Ventilation

Answer 3

• Obstructive disease (e.g., COPD)
• Compliance problems
• Exercise (ventilation can increase up to 10-fold)
• High altitude
• Gravity (introduces regional variations in ventilation)

Question 4

Total Work Breathing

Answer 4

Total Work = Elastic Work + Resistance Work

Question 5

Total Work Breathing

Answer 5

Total Work = Elastic Work + Resistance Work

• elastic work- effort it takes to expand lungs
• -high at high tidal volume and low frequency
• resistance- effort it takes to open lungs against resistance in airway
• -high at low tidal volume and high frequency

Question 6

Anatomical Dead Space

Answer 6

• 30% of total lung volume
• dead space is volume of lung that does not exchange gas
• the dead space in that portion of the respiratory system which is external to the alveoli and includes the air-conveying ducts from the nostrils to the terminal bronchioles

Question 7

Alveolar Dead Space

Answer 7

-The difference between physiological dead space and anatomical dead space, representing that part of the physiological dead space resulting from ventilation of relatively underperfused or nonperfused alveoli.

Question 8

Physiologic Dead Space

Answer 8

• physiologic dead space = anatomical dead space + alveolar dead space
• the total dead space in the entire respiratory system including the alveoli

Question 9

Residual Volume (RV)

Answer 9

-the volume of air remaining in the lungs after a maximal exhalation

Question 10

Functional Residual Capacity (FRC)

Answer 10

-the volume in the lungs at the end-expiratory position

Question 11

Total Lung Capacity (TLC)

Answer 11

-the volume in the lungs at maximal inflation, the sum of VC and RV

Question 12

Vital Capacity (VC)

Answer 12

-the volume of air breathed out after the deepest inhalation.

Question 13

Forced Expiratory Volume 1 (FEV1)

Answer 13

-Volume that has been exhaled at the end of the first second of forced expiration

Question 14

Forced Vital Capacity (FVC)

Answer 14

-the determination of the vital capacity from a maximally forced expiratory effort

Question 15

FEV1/FVC

Answer 15

• calculated ratio used in the diagnosis of obstructive and restrictive lung disease
• It represents the proportion of a person’s vital capacity that they are able to expire in the first second of expiration
• normal values are approximately 80%

Question 16

RV, FRC, TLC, VC, FEV1/FVC in Pulmonary Fibrosis (restrictive)

Answer 16

• RV: dec
• FRC: dec
• TLC: DEC.
• VC: DEC.
• FEV1/FVC: no change or small inc.

Question 17

RV, FRC, TLC, VC, FEV1/FVC in Bronchitis (obstructive)

Answer 17

• RV: inc.
• FRC: inc.
• TLC: same
• VC: dec.
• FEV1/FVC: DEC.

Question 18

Partial Pressure of Inspired Oxygen (PiO2)

Answer 18

• can vary by altitude
• dalton’s law: PiO2 = (PB - 47 torr) x FO2
• if breathing 100% O2, FO2 = 100%, PiO2 = 713 torr
• typical PiO2 at sea leve: 150
• typical PiO2 at altitude: 40 torr

Question 19

Respiratory Exchange Ratio (R)

Answer 19

R = CO2 produced / O2 consumed

Question 20

Alveolar Gas Equation

Answer 20

PAO2 = PiO2 - (PACO2/R)

Question 21

______ is rate-limiting step in CO2 removal from blood.

Answer 21

ventilation

Question 22

Alveolar Ventilation Equation

Answer 22

PaCO2 = (VCO2/Va) x k

-can substitute PACO2 for PaCO2

Question 23

Hypoventilation

Answer 23

-low VA and high PaCO2, happens during severe obstructive disease

Question 24

Hyperventilation

Answer 24

-high VA and low PaCO2, happens at high altitude

Question 25

Hyperpnia

Answer 25

-high VA and normal PaCO2, happens during exercise

Question 26

Solubility Coefficient

Answer 26

- aO2 = 0.0013 mM/torr | - aCO2 = 0.03 mM/torr

Question 27

Oxyhemoglobin Dissociation Curve

Answer 27

- pressure on x axis - O2 saturation on y axis - S shaped curve

Question 28

Diffusion Disorders

Answer 28

- interstitial lung disease (inc. distance between alveoli and capillary) - emphysema (dec. surface area due to breakdown in lung tissue)

Question 29

Perfusion

Answer 29

- blood flow in lung - factors that affect perfusion: O2 tension (in hypoxia, vasoconstriction occurs), capillary recruitment, gravity (more at bottom than top of lung)

Question 30

V/Q mismatch

Answer 30

- V = ventilation - Q = perfusion - different in different parts of lung - V/Q mismatch will lower PaO2 - V/Q mismatch can affect O2, but will not affect CO2

Question 31

Causes of V/Q Mismatch

Answer 31

- resistance/compliance problems (mild to moderate as well as severe disease conditions can cause V/Q mismatch) - pulmonary embolism - gravity

Question 32

Gravity Effect on Ventilation and Perfusion in Upright Person

Answer 32

- high perfusion in lower lung | - high ventilation in upper lung

Question 33

Oxygen Off-Loading

Answer 33

- before oxygen can be taken up it must unbind from hemoglobin (oxygen offloading) - reduced affinity for O2 corresponds to inc. O2 off-loading - affected by PCO2, temp, [H+], 2, 3 diphosphoglycerate (hypoxia)

Question 34

O2 Carrying Capacity

Answer 34

-maximal O2 that can be carried by a particular amount of Hb

Question 35

DO2

Answer 35

-volume of O2 delivered in 1 minute

Question 36

Hypoxemia

Answer 36

-PaO2

Question 37

Ways CO2 is Carried in Blood

Answer 37

- dissolved gas - bicarbonate produced in reaction with H2O (highly soluble) - carbamino compounds- tranported on proteins (hemoglobin)