Chapter 13: The Respiratory System

Vocabulary flashcards covering key terms from the Respiratory System lecture notes.

Respiratory system

The body system that provides oxygen to body tissues, disposes of carbon dioxide, and helps regulate blood pH; includes airways, the lungs, and respiratory membranes where gas exchange occurs.

Alveoli

Tiny air sacs in the lungs where gas exchange with the blood occurs; surrounded by pulmonary capillaries and lined by a thin squamous epithelium.

Respiratory membrane

The thin barrier between alveolar air and blood through which gases diffuse (alveolar epithelium, fused basement membranes, and capillary endothelium).

Surfactant

Lipid secreted by alveolar cells that lowers surface tension and prevents alveolar collapse during breathing.

Alveolar macrophages

Dust cells in alveoli that phagocytose bacteria and debris to keep the alveolar surfaces clean.

Nasal cavity

Internal space of the nose that warms, humidifies, and filters air before it reaches the lungs.

Olfactory epithelium

Mucous membrane in the superior part of the nasal cavity containing receptors for the sense of smell.

Respiratory mucosa

Mucosal lining of the nasal cavity and much of the respiratory tract that warms air and traps debris with mucus and cilia.

Cilia

Tiny hairlike projections on respiratory mucosa that move mucus toward the throat for swallowing or expectoration.

Nasal conchae

Three bony projections (superior, middle, inferior) in the nasal cavity that increase surface area and air turbulence to filter and warm air.

Nasolacrimal ducts

Ducts that drain tears from the eyes into the nasal cavity.

Pharynx

Muscular throat passageway shared by the respiratory and digestive systems; has nasopharynx, oropharynx, and laryngopharynx.

Nasopharynx

Upper part of the pharynx behind the nasal cavity; air passage; contains openings to pharyngotympanic tubes and pharyngeal tonsils.

Oropharynx

Pharyngeal region behind the oral cavity; passage for food and air; contains palatine and lingual tonsils.

Laryngopharynx

Lower part of the pharynx that routes air to the larynx and food to the esophagus.

Epiglottis

Elastic cartilage flap that covers the laryngeal opening during swallowing to prevent food from entering the airway.

Larynx

Voice box that routes air to the trachea and food to the esophagus; houses vocal cords and protects the lower airway.

Thyroid cartilage

Largest hyaline cartilage of the larynx; protrudes anteriorly as the Adam's apple.

Vocal cords

True vocal cords; mucosal folds that vibrate to produce sound as air passes; controlled by laryngeal muscles.

Glottis

The slitlike opening between the vocal folds through which air passes.

Trachea

Windpipe; air passage from the larynx to the bronchi; reinforced with C-shaped rings of hyaline cartilage and lined with ciliated mucosa.

Right main bronchus

Wider, shorter, and more vertical than the left; common site for inhaled objects to lodge.

Left main bronchus

Longer, narrower bronchus that enters the left lung.

Main bronchi

The right and left primary bronchi formed by division of the trachea that enter the lungs and branch into smaller airways.

Bronchioles

Smaller branches of the airways that lead to the alveolar ducts and sacs; lack cartilage.

Alveolar ducts

Small passages that lead from the respiratory bronchioles to the alveolar sacs and alveoli.

Alveolar sacs

Clusters of alveoli that receive air from alveolar ducts; site of gas exchange.

Pleura

Two-layer serous membranes around the lungs: visceral pleura covers the lungs and parietal pleura lines the thoracic cavity; the space between them contains pleural fluid.

Visceral pleura

The membrane that tightly covers the surface of each lung.

Parietal pleura

The membrane lining the internal thoracic cavity and surrounding structures.

Pleural cavity

Potential space between visceral and parietal pleura that contains pleural fluid to reduce friction.

Diaphragm

Dome-shaped muscle that contracts to increase thoracic volume during inspiration.

Intrapulmonary pressure

Pressure inside the lungs; becomes negative during inspiration and positive during expiration to drive airflow.

Intrapleural pressure

Pressure within the pleural cavity; normally negative and critical for keeping lungs inflated; equality with atmospheric pressure causes collapse.

Atelectasis

Lung collapse due to air in the pleural space or other factors causing lung to collapse.

Pneumothorax

Air in the pleural space causing partial or complete lung collapse.

Hemoglobin

Protein in red blood cells that binds oxygen and carbon dioxide; transports gases in the blood.

Oxyhemoglobin

Hemoglobin bound to oxygen; carries O2 in the blood.

Bicarbonate (HCO3-)

Main form in which CO2 is transported in plasma; formed in red blood cells and acts as a buffer to maintain blood pH.

External respiration

Gas exchange between alveolar air and pulmonary blood.