Respiratory System

Vocabulary flashcards for reviewing the respiratory system lecture notes.

What are the hollow passages that collectively exchange gases in the respiratory system?

The respiratory tract.

How is the respiratory tract classified anatomically?

Into the upper and lower tracts. The upper respiratory tract includes passageways from the nasal cavity to the larynx, and the lower respiratory tract includes passageways from the trachea to the terminal structures in the alveoli.

Describe alveoli.

Alveoli are tiny air sacs, arranged in grapelike clusters, where gases are exchanged.

Describe the conducting zone of the respiratory system.

The conducting zone has conduits through which air travels on its way into (inspired or inhaled) and out (expired or exhaled) of the body. Air is filtered, warmed, and moistened as it travels through this zone, which includes structures from the nose and nasal cavity to the bronchioles.

Describe the respiratory zone.

The respiratory zone is where gas exchange occurs and includes only the structures that contain the alveoli.

What is the primary function of the respiratory system?

Respiration, a process that provides the body’s cells with oxygen and removes the waste product carbon dioxide.

Name some functions of the respiratory system besides respiration.

Speech and sound production, sense of smell, increasing pressure in the abdominopelvic cavity, assisting with venous blood and lymph flow, maintenance of acid-base balance, and production of angiotensin-II.

Summarize the functions of the nose and nasal cavity.

Inhaled air is warmed and humidified, debris is filtered and antibacterial substances are secreted, olfactory receptors are housed there, and the nasal cavity enhances the resonance of the voice.

What is the function of the nasal conchae?

The nasal conchae curl around narrow passages (meatuses) creating turbulence that rids dust and debris from inspired air.

What types of epithelium are found lining the nasal cavity?

The vestibule is lined with stratified squamous epithelium. Posterior to the vestibule, it changes to olfactory mucosa and respiratory mucosa, which is composed of pseudostratified ciliated columnar epithelium and goblet cells.

What are the functions of the larynx?

The larynx keeps food and liquids out of the remaining respiratory tract and houses the vocal cords that are involved in sound production.

What is the shape and function of the cartilage rings in the trachea?

They are C-shaped rings of hyaline cartilage. They are supportive enough to keep the trachea open (patent) but flexible enough to allow the trachea to change diameter during pulmonary ventilation.

Describe the initial branching of the bronchial tree.

From the carina of the trachea, air enters either the left or right primary bronchus. Each primary bronchus branches into secondary bronchi, which branch into about 10 smaller tertiary bronchi per lung, and then continue to branch into smaller branches.

Summarize the histological changes seen in the bronchial tree beyond the primary bronchi as airways get smaller.

Cartilage changes from C-shape to complete rings to progressively fewer irregular plates. Epithelium changes from respiratory epithelium to columnar cells, and then to simple cuboidal epithelium in bronchioles. The amount of smooth muscle increases while hyaline cartilage decreases.

Name and describe the three cell types found in the alveolar wall.

Type I alveolar cells(squamous, 90% of cells, thin for rapid gas diffusion), Type II alveolar cells (small cuboidal, synthesize surfactant to reduce surface tension), and Alveolar macrophages (mobile phagocytes, clean up debris).

What is the function of pleural fluid?

Pleural fluid fills the space between the pleural membranes and serves to lubricate the delicate surfaces of the lungs as they expand and contract during pulmonary ventilation.

What are the two phases of pulmonary ventilation?

Inspiration (inhalation) to bring air into the lungs, and expiration (exhalation) that moves air out of the lungs.

Describe Boyle’s law.

At constant temperature and number of gas molecules, the pressure and volume of a gas are inversely related. As volume increases, pressure decreases, and as volume decreases, pressure increases.

Name two inspiratory muscles involved in ventilation.

Diaphragm and external intercostals.

Name the three primary physical factors that influence the effectiveness of pulmonary ventilation.

Airway resistance, alveolar surface tension, and pulmonary compliance.

What is tidal volume (TV)?

Tidal volume (TV) is the amount of air inspired or expired during normal quiet ventilation, typically about 500 ml in a healthy adult.

How is vital capacity calculated?

Vital capacity is calculated as (TV + IRV + ERV), representing the total amount of exchangeable air that can move in and out of the lungs.

What are the two processes involved in gas exchange?

Pulmonary gas exchange (between alveoli and blood) and tissue gas exchange (between blood and body cells).

Describe Dalton’s law of partial pressures.

Each gas in a mixture exerts its own partial pressure, and the total pressure of a gas mixture is the sum of the partial pressures of all its component gases. Partial pressure determines gas movement by diffusion.

What is pulmonary gas exchange (external respiration)?

The diffusion of gases between the alveoli and blood. Oxygen diffuses from alveoli air into blood, and carbon dioxide diffuses from blood into alveoli air.

What drives the movement of gases during pulmonary gas exchange?

Pressure gradientscreated by the difference in partial pressures of oxygen and carbon dioxide between the air in the alveoli and in the pulmonary capillaries.

Besides partial pressures and gas solubility, what three factors affect the efficiency of pulmonary gas exchange?

The surface area of the respiratory membrane, the thickness of the respiratory membrane, and ventilation-perfusion matching.

What protein facilitates oxygen transport in the blood?

The protein hemoglobin (Hb), found in erythrocytes. Each hemoglobin protein can carry up to 4 oxygen molecules.

What are the three ways carbon dioxide is transported from tissues back to the lungs in the blood?

Dissolved in plasma (7–10%), bound to Hb as carbaminohemoglobin (about 20%), and as bicarbonate ions(70%).

What region of the brain controls the basic pattern of ventilation?

The brainstem, particularly the medulla oblongata. Neurons in the pons influence the respiratory rhythm but don't maintain eupnea.

What is the role of goblet cells in the respiratory system?

Goblet cells secrete mucus, which traps debris and pathogens, protecting the respiratory epithelium.

Describe the function of surfactant in the alveoli.

Surfactant reduces surface tension in the alveoli, preventing them from collapsing and making it easier for gas exchange to occur.

What is the effect of increased airway resistance on pulmonary ventilation?

Increased airway resistance makes