Lung Structure & Function

Question 1

How is pulmonary ventilation calculated?

Answer 1

V=fxTV . Ventilations rate is equal to the frequency of breathing times the tidal volume. Tidal volume is the volume of air that moves into or out of the lung in one breath.

Question 2

What is a typical ventilation in L/breath and what is a typical rate? During exercise what can this increase to?

Answer 2

.5 L/breath time 15 breaths/min = 7.5 L/min. During exercise this could reach 120 L/min as both breathing frequency and tidal volume increase.

Question 3

What are the values for Ambient Temperature and Pressure Sat’d (ATPS)?

Answer 3

25 C, 760 mmHg, 24 mmHg water

This is the case in the spirometer

Question 4

What are the values for Body Temperature and Pressure Sat’d (BTPS)?

Answer 4

37 C, 760 mmHg, 47 mmHg water

This is the case in the lung

Question 5

What are the values for Standard Temperature and Pressure Dry (STPD)?

Answer 5

0 C, 760 mmHg, 0 mmHg water

Question 6

When do you convert from ATPS to STPD?

Answer 6

To calculate O2 consumption and CO2 production rates.

Question 7

When do you confer from ATPS to BTPS?

Answer 7

For lung volumes

Question 8

V at BTPS = X V at ATPS

Answer 8

1.07 V. A small but significant difference due to the presence of water vapor pressure.

Question 9

What comprises the conductive zone of the lungs? What functions does it have? What cell types does it contain?

Answer 9

The trachea, bronchi, bronchioles and terminal bronchioles (first 16 branches). There is no exchange between gas and blood here. The surfaces have ciliated to propel mucous secreted by goblet cells. Makes up the dead space of about 150 mL.

Question 10

What comprises the respiratory (and transitional) zone? What cell types does it contain?

Answer 10

respiratory bronchioles, alveolar ducts and alveolar sacs (last 7 branches). Type 1 alveolar epithelial cells. Type II alveolar cells.

Question 11

Type 1 and Type 2 alveolar cells are contained in which zone of the respiratory pathway?

Answer 11

The respiratory zone

Question 12

Goblet cells and cilia are contained in which zone of the respiratory pathway?

Answer 12

The conducting zone.

Question 13

In the alveoli which process dominates, diffusion or bulk flow?

Answer 13

Diffusion. The large surface area (Q= A x v) is why this is true. The huge surface area of the alveoli slows the speed of air to very low velocity.

Question 14

Do dissolved gases contribute to blood pressure or volume?

Answer 14

No, dissolved in a liquid gas does not exert pressure nor a volume.

Question 15

When dealing with wet gases what is the equation for the pressure of gas i?

Answer 15

Pi=Fi (Pt - Ph2o)

Question 16

From Henry’s law describe the concentration of a dissolved gas in a liquid

Answer 16

Henry’s law states that the concentration of a dissolved gas at equilibrium is proportional to the partial pressure of the gas above the solution.

Question 17

What is alveolar dead space?

Answer 17

Alveoli that are ventilated but not perfused

Question 18

What is trapped volume?

Answer 18

Alveoli that are perfused but not ventilatedq

Question 19

What is respiratory quotient? What is the formula for it?

Answer 19

It is a ratio of tissue metabolic production of CO2 and consumption of O2. RQ = CO2/ O2 where CO2 and O2 refer to the tissue.

Question 20

What is Respiratory exchange ratio? What is the formula for it?

Answer 20

It is measured by analysis of inspired and expired gas at the lung. RE = CO2/O2 where CO2 and O2 refer to the lung.

Question 21

What does the value of respiratory quotient dependent upon?

Answer 21

The metabolic substrate being oxidize. 0.7 for pure fat and 1.0 for pure carbs. Averaging about .85 for a normal diet.