Respiratory Physiology Respiratory System Supply the body with

Respiratory Physiology

Respiratory System - Supply the body with o 2 and dispose of co 2 Respiration: • Pulmonary ventilation (~breathing) • External respiration (gas exchange between blood & lungs) • Transport of respiratory gases (transport of gases between the lungs and tissues cells, accomplished by the cardiovascular system, using blood as the transport vehicle) • Internal respiration (gas exchange between systemic blood & tissue cells)

Lung Volumes & Capacities • Spirometry – Spirogram: record of volume change vs. time (inspiration & expiration) – Spirometer

Total Lung Capacities • Tidal Volume (TV): amount of air inhaled or exhaled with each breath under resting conditions ~500 m. L • Inspiratory Reserve Volume (IRV): amount of air that can be forcefully inhaled at the end of a tidal inhalation M~3300 m. L vs. F~1900 m. L • Expiratory Reserve Volume (ERV): amount of air that can be maximally exhaled at the end of a tidal exhalation M~1000 m. L vs. F~700 m. L • Residual Volume (RV): the volume of gas remaining in the lungs at the end of a maximal respiration M~1200 m. L (33% of VC) vs. F~1000 m. L (25% of VC)

Figure 2

Pulmonary Capacities • Inspiratory Capacity (IC): • IC = TV + IRV • Expiratory Capacity (EC): • EC = TV + ERV • Functional Residual Capacity (FRC): • FRC = ERV + RV • Vital Capacity (VC): • VC = TV + IRV + ERV • Total Lung Capacity • TLC = TV + IRV + ERV +RV

Predicted VC • Male – VC = 0. 052 H – 0. 022 A – 3. 60 • Female – VC = 0. 041 H – 0. 018 A – 2. 69 VC= L H= cm A= years

Factors • • Age- PC decrease Gender- F<M Weight- increase with size Physical condition- increase with activity

Obstructive vs. Restrictive Lung Disease • Obstructive pulmonary disease: airflow into & out of the lungs is reduced – Ex. Asthma (brochial tubes), Emphysema (alveoli), COPD (lung) • Restrictive pulmonary disease: reduced lung volume (TLC, VC, or resting lung vol) – Ex. Intrinsic (lungs) vs. extrinsic (chest wall) lung diseases

Experiment B • Forced VC (FVC): maximal amount of air that a person can forcibly exhale after a maximal inhalation • Forced EV (FEV): % of FVC that a person forcibly expels in intervals of 1, 2, & 3 sec – FEV = (vol of air exhaled in 1 sec/ VC) X 100

Experiment B: segment 2 MVV • DO THIS 1 st!!!!! • Maximal Voluntary Ventilation (MVV): pulmonary function test that combines volume & flow rates to assess overall pulmonary ventilation. – Hyperventilate for 15 sec • MVV = (avg vol/cycle) X (number of cycles/min)