Respiration, Gas Exchange, and Respiratory Terminology

Flashcards covering ventilation-perfusion coupling, factors affecting gas exchange, partial pressures, respiratory patterns, and lung volume measurements.

Ventilation-Perfusion Coupling

The ratio between the amount of air flowing into the alveolus (ventilation) and the flow of blood through the surrounding capillaries (perfusion).

Pulmonary Vascular Response to Poor Airflow

The automatic constriction of pulmonary vessels in a portion of the lung experiencing poor airflow and falling blood oxygen levels, redirecting blood to better ventilated alveoli.

Pulmonary Vascular Response to Good Airflow

The automatic dilation of pulmonary vessels in an area of the lung experiencing good airflow and rising oxygen levels, increasing blood flow to take up available oxygen.

Factors Affecting Gas Exchange

Key physiological factors—including adequate airway, respiratory rate, alveolar surface area, pressure gradients, compliant lung tissue, and blood supply—that determine optimal oxygenation.

Partial Pressure of Inspired Air

The partial pressures of gases in breathed air before reaching the alveoli, characterized by a $P_{O2}$ of $159$ and a $P_{CO2}$ of $0.3$.

Partial Pressure in Alveoli

The partial pressures of gases within alveolar air, defined by a $P_{O2}$ of $104$ and a $P_{CO2}$ of $40$.

Partial Pressure in Deoxygenated Pulmonary Capillaries

The partial pressures of blood entering pulmonary capillaries prior to gas exchange, characterized by a $P_{O2}$ of $40$ and a $P_{CO2}$ of $46$.

Partial Pressure in Oxygenated Pulmonary Capillaries

The partial pressures of blood leaving pulmonary capillaries after gas exchange, characterized by a $P_{O2}$ of $100$ and a $P_{CO2}$ of $40$.

Partial Pressure in Tissue Fluid

The partial pressures of fluid surrounding body tissues, characterized by a $P_{O2}$ of $40$ and a $P_{CO2}$ of $46$.

Total Atmospheric Pressure

The total pressure exerted by the surrounding air mixture, equal to $760\text{ mm Hg}$.

Partial Pressure

The contribution of a single gas to total atmospheric pressure in a gas mixture, symbolized by 'P' followed by the gas formula.

Abdominal Thrusts

An emergency procedure used to dislodge an object from a choking person's trachea by utilizing the residual volume of air in the lungs.

Apnea

Temporary cessation of breathing.

Biot's Respirations

Abrupt, irregular breathing pattern in which periods of apnea alternate with periods of breathing that are consistent in rate and depth, often resulting from increased intracranial pressure.

Bradypnea

Abnormally slow breathing.

Cheyne-Stokes Respirations

Cyclical breathing pattern that begins with an increase in rate and depth of respirations (crescendo effect) followed by a gradual decrease in rate and depth (decrescendo effect), culminating in a short period of apnea before repeating.

Dyspnea

Labored or difficult breathing.

Eupnea

Relaxed, quiet breathing.

Hyperpnea

Increased rate of breathing that may be physiological (such as during exercise) or pathological (such as from severe infection).

Hyperventilation

Increased rate of respirations resulting in lowered blood levels of carbon dioxide, often resulting from anxiety.

Hypoventilation

Reduced rate and depth of respirations, resulting in increased blood levels of carbon dioxide.

Kussmaul Respiration

Very deep, gasping respirations associated with diabetic ketoacidosis.

Orthopnea

Labored breathing that occurs when a person is lying flat but improves when standing or sitting up; a classic symptom of left ventricular heart failure.

Tachypnea

Rapid breathing.

Spirometer

A device used to measure lung capacity by having a person breathe through it.

Tidal Volume

The amount of air inhaled and exhaled during quiet breathing, equal to $500\text{ ml}$ in a healthy young adult.

Inspiratory Reserve Volume

The amount of air that can be inhaled using maximum effort after a normal inspiration, equal to $3000\text{ ml}$.

Expiratory Reserve Volume

The amount of air that can be exhaled after a normal expiration by using maximum effort, equal to $1200\text{ ml}$.

Residual Volume

The amount of air remaining in the lungs after a forced expiration ($1300\text{ ml}$), which ensures continuous gas exchange between breaths.

Vital Capacity

The maximum amount of air that can be inhaled and exhaled with the deepest possible breath ($4700\text{ ml}$), calculated as tidal volume combined with inspiratory and expiratory reserve volumes.

Total Lung Capacity

The maximum amount of air that the lungs can contain ($6000\text{ ml}$), calculated as vital capacity plus residual volume.

Anatomical Dead Space

The air in conducting airways (about $150\text{ ml}$) that does not reach the alveoli and cannot participate in gas exchange.

Physiological Dead Space

All the air in conducting airways (anatomical dead space) plus the air in any alveoli that are poorly perfused and less efficient in gas exchange.