BIO 2341 Chapter 22: Respiratory System

Comprehensive vocabulary flashcards covering anatomical structures, lung volumes and capacities, regulatory centers, and physiological mechanisms of gas exchange and transport in the respiratory system.

Pulmonary surfactant

A substance that functions primarily to reduce alveolar surface tension.

Dorsal respiratory group (DRG)

A brainstem group that integrates chemoreceptor and pulmonary receptor input to adjust breathing.

Hypercapnia

An abnormally elevated blood carbon dioxide level.

Lung compliance

The ease with which the lungs and thoracic cavity expand.

Residual volume (RV)

The volume of air that remains in the lungs after a maximal forced exhalation.

Vital capacity (VC)

The greatest exchangeable volume exhaled after maximal inhalation, calculated as $\text{IRV} + \text{TV} + \text{ERV}$.

Boyle's law

A gas law describing the inverse relationship between pressure and volume at constant temperature; as alveolar volume increases, pressure decreases.

External respiration

Gas exchange occurring between the alveoli and pulmonary capillary blood, during which carbon dioxide moves from pulmonary capillaries to the alveoli.

Internal respiration

Gas exchange between systemic capillary blood and body tissues, where oxygen diffuses down its gradient into tissues and carbon dioxide diffuses into the blood.

Carbonic anhydrase

An enzyme that catalyzes the reversible conversion of $\text{CO}_2$ and $\text{H}_2\text{O}$ to carbonic acid ($\text{H}_2\text{CO}_3$).

Chloride shift

The process that maintains electrical neutrality as bicarbonate moves across the red blood cell membrane by exchanging bicarbonate for chloride via an antiporter.

Haldane effect

The physiological phenomenon where deoxygenated hemoglobin binds and carries carbon dioxide and hydrogen ions more readily than oxygenated hemoglobin.

Visceral pleura

The serous membrane layer that directly covers the external surface of the lungs.

Parietal pleura

The membrane layer that lines the inner surface of the thoracic wall.

Pleural fluid

A lubricating substance located in the pleural cavity that reduces friction between the pleural layers during respiration.

Hering-Breuer inflation reflex

A pulmonary reflex mechanism that helps prevent excessive lung inflation.

Pre-Bötzinger complex

A medullary neuronal complex responsible for helping generate the basic rhythm of respiration.

Pontine respiratory group (PRG)

A brainstem group that smooths the transition between inspiration and expiration.

Hypocapnia

An abnormally low blood carbon dioxide level.

Apnea

A temporary cessation of breathing.

Dyspnea

Difficult or uncomfortable breathing.

Tidal volume (TV)

The volume of air moved into or out of the lungs during a single normal, resting breath.

Inspiratory reserve volume (IRV)

The additional volume of air that can be forcibly inhaled following a normal tidal inhalation.

Total lung capacity (TLC)

All air contained in the lungs after a maximal inspiration, calculated as $\text{VC} + \text{RV}$.

Partial pressure

The individual pressure exerted by a single specific gas within a mixture of gases.

Oxyhemoglobin

A hemoglobin molecule with oxygen reversibly attached to its heme groups.

Carbaminohemoglobin

A hemoglobin molecule with carbon dioxide bound directly to its globin amino chains.

Airway resistance

The frictional opposition to airflow encountered through the respiratory passages.

Bronchodilation

The relaxation of airway smooth muscle that increases luminal diameter and widens the airway.

Buffer

A chemical system that resists sudden and drastic changes in pH.

Respiratory membrane

The thin alveolar-capillary barrier across which oxygen and carbon dioxide diffuse between air and blood.

Hypoventilation

Ventilation that is insufficient to remove the carbon dioxide produced by the body, promoting $\text{CO}_2$ retention, causing hypercapnia, and lowering blood pH.

Hyperventilation

Ventilation that removes $\text{CO}_2$ faster than the body produces it, leading to hypocapnia and an increase in blood pH.

Bohr effect

The reduction in hemoglobin's affinity for oxygen caused by an increase in carbon dioxide or hydrogen ion concentration, promoting oxygen unloading.

Bicarbonate ion ($\text{HCO}_3^-$)

The primary transport form of carbon dioxide in the blood (accounting for approximately $70\%$) and a key component of the extracellular buffer system.