January 12, 2016 - Respiratory Physiology

Question 1

Conducting and Respiratory Zones

Answer 1

Typically, no gas exchange occurs until after branch (z) 17 or so.

Question 2

Abbreviations in Respirology

Answer 2

P = partial pressure of a gas

S = saturation of hemoglobin

a = arterial

A = alveolar

V = volume (in L)

V_E = minute ventilation (ventilation per min)

V_T = tidal volume (~500cc/min)

Question 3

Tidal Volume

Answer 3

The lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young adult, tidal volume is approximately 500mL per inspiration.

Question 4

ABG Format

Answer 4

pH / P_aCO₂ / P_aO₂ / HCO₃

Question 5

Anatomical vs. Physiological Dead Space

Answer 5

Anatomical dead space is the portion of the airways (such as the mouth and trachea to the bronchioles) which conducts gas to the alveoli. No gas exchange is possible in these spaces.

Physiological dead space / alveolar dead space is the sum of the volumes of those alveoli which have little or no blood flowing through their adjacent pulmonary capillaries. Physiological/alveolar dead space is negligable in healthy individuals, but can increase dramatically in some lung diseases due to ventilation-perfusion mismatch.

Question 6

Ventilation/Perfusion Ratio

Answer 6

V/Q Ratio

Is a measurement used to assess the efficiency and adequacy of the matching two variables of ventilation and perfusion.

V - ventilation - the air that reaches the alveoli

Q - perfusion - the blood that reaches the alveoli

Can be measured with a ventilation/perfusion scan

Question 7

Spirometry

Answer 7

The most common of pulmonary function tests (PFTs). Measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled.

Question 8

P_ACO₂ vs. P_aCO₂

Answer 8

They are basically equivalent

Question 9

Oxygen Uptake Along the Pulmonary Capillary

Answer 9

Normally, the time the blood comes into contact with the alveoli is 0.75 seconds. When you are doing physical exercise, this time drops to 0.25 seconds.

Cardiac output decreases the time spent in contact with the alveoli, and can decrease the amount of oxygen that is being absorbed.