15. Respiratory System

Essential vocabulary flashcards covering anatomical divisions, structures, respiratory mechanics, gas exchange processes, and acid-base balance of the respiratory system.

Upper Respiratory Tract

The division of the respiratory tract consisting of the nasal cavity, pharynx, larynx, and trachea, which terminates immediately before the bifurcation of the trachea.

Lower Respiratory Tract

The division of the respiratory tract that begins immediately after the bifurcation of the trachea and includes the lungs, bronchial tree, alveoli, and pleural cavity.

External Nares

The nostrils; the outermost respiratory structures that lead inhaled air into the main nasal cavity.

Turbinate Bones

Scroll-like bones that populate the majority of the nasal cavity and form convoluted passageways when lined with mucous membranes.

Nasal Meatus

The convoluted space and passageways between the turbinate bones that efficiently condition, humidify, and filter inhaled air.

Nasal Sinuses

Air-filled cranial cavities whose primary function is to provide a consistent supply of surface mucus to protect the nasal cavity from debris and pathogens.

Internal Nares

Internal nasal openings similar in shape to the nostrils that transition air from the nasal cavity into the nasopharynx.

Nasopharynx

The dorsal section of the pharynx formed by the nasal cavity that directs air caudally toward the larynx.

Oropharynx

The ventral section of the pharynx formed by the oral cavity.

Laryngopharynx

The section of the pharynx formed by the junction of the nasopharynx and oropharynx that surrounds the upper larynx and leads to either the trachea or the esophagus.

Larynx

The initial cartilaginous structure of the trachea responsible for vocal production, preventing foreign object inhalation, and controlling air intake.

Epiglottis

A cartilaginous flap of the larynx that opens cranioventrally during respiration and closes during ingestion to act as a protective trapdoor for the trachea.

Glottis

The slit-like opening between the two vocal cords leading to the trachea, utilized for vocal production, air control, and maintaining thoracic pressure.

Trachea

The windpipe that terminates the upper respiratory tract; it lies ventral to the esophagus and is kept patent by C-shaped rings of hyaline cartilage.

Bifurcation of the Trachea

The anatomical splitting of the trachea into the left and right primary bronchi, situated immediately dorsal to the heart.

Bronchial Tree

The branching network of airways continuing from the bifurcation of the trachea into the lungs, dividing progressively until reaching microscopic gas-exchanging units.

Bronchodilation

The expansion or dilation of the smooth-muscle airways within the bronchial tree.

Bronchoconstriction

The narrowing or constriction of the smooth-muscle airways within the bronchial tree.

Alveoli

Microscopic, capillary-surrounded air sacs in the lungs that constitute the smallest functional units of the respiratory system where gas exchange takes place.

Pleura

The serous membranes that envelop the lungs and line the thoracic cavity.

Visceral Pleura

The inner layer of the pleural serous membrane that is in direct contact with the surface of the lungs.

Parietal Pleura

The outer layer of the pleural serous membrane situated on the thoracic wall opposite the visceral pleura.

Pleural Cavity

The potential space enclosed between the visceral pleura and parietal pleura surrounding the lungs.

Pleural Effusion

The abnormal, excessive accumulation of fluid within the pleural space.

Pulmonary Edema

The abnormal accumulation of fluid directly within the alveolar spaces of the lungs.

Negative Pressure (Thorax)

The sub-atmospheric pressure maintained within the chest cavity that facilitates easy air intake during inhalation while allowing thorax muscles to expel air.

Diaphragm

The primary dome-shaped muscle of respiration that concaves cranially toward the lungs at rest, projects caudally during inspiration, and relaxes cranially during expiration.

External Intercostals

Respiratory muscles between the ribs that contract during inspiration to expand the ribcage, and relax during expiration.

Internal Intercostals

Respiratory muscles between the ribs that contract during expiration to pull the ribs inward and reduce the volume of the ribcage.

External Respiration

The passive diffusion and exchange of oxygen ($O_2$) and carbon dioxide ($CO_2$) across the alveolar-capillary membranes between inhaled air and pulmonary blood.

Internal Respiration

The passive diffusion and exchange of oxygen ($O_2$) and carbon dioxide ($CO_2$) between systemic capillary blood and metabolizing body tissues or muscles.

Respiratory Acidosis

A systemic drop in blood pH resulting from inadequate ventilation, wherein retained carbon dioxide ($CO_2$) combines with water ($H_2O$) to form carbonic acid ($H_2CO_3$).