Respiratory system

Spirometry Test

A test used to measure lung volumes and capacities.

Tidal Volume (TV)

Amount of air inhaled/exhaled in a normal breath (≈ 500 mL).

Inspiratory Reserve Volume (IRV)

Extra air inhaled after normal inspiration (≈ 3100 mL).

Expiratory Reserve Volume (ERV)

Extra air exhaled after normal expiration (≈ 1200 mL).

Residual Volume (RV)

Air remaining in lungs after maximum expiration (≈ 1200 mL).

Vital Capacity (VC)

Maximum air exhaled after maximum inhalation (TV + IRV + ERV ≈ 4800 mL).

Total Lung Capacity (TLC)

Total volume of air lungs can hold (≈ 6000 mL).

Functional Residual Capacity (FRC)

Air remaining after normal exhalation (ERV + RV).

Anatomical Dead Space

Air in conducting zone not used for gas exchange (≈ 150 mL).

Restrictive Lung Disease

Decreased lung compliance and reduced lung volumes.

Example of Restrictive Disease

Pulmonary fibrosis, respiratory distress syndrome.

Obstructive Lung Disease

Increased airway resistance and reduced airflow.

Example of Obstructive Disease

Emphysema, asthma, pulmonary edema.

COPD

Chronic obstructive pulmonary disease (group of obstructive diseases).

FEV1

Forced expiratory volume in 1 second (measures rate of expiration).

Purpose of FEV1

Used to diagnose obstructive vs restrictive diseases.

Normal Intrathoracic Pressure

Negative pressure (≈ -3 mm Hg) helps keep lungs expanded.

Pneumothorax

Air enters pleural space causing lung collapse.

Effect of Pneumothorax

Lung collapses to unstretched size.

Tension Pneumothorax

Severe condition where pressure shifts organs (heart/trachea).

Effect of Tension Pneumothorax

Heart and trachea shift to opposite side.

IRV Lab Note

Should be ≈ 3000 mL but may incorrectly display as 2000 mL in simulation.