Respiratory System: Part 1 - Upper and Lower Respiratory Anatomy and Physiology

Comprehensive vocabulary flashcards covering anatomical terminology, conducting and respiratory zones, laryngeal and tracheal structures, bronchial divisions, pleural membranes, and histological components of the respiratory membrane from Pharm 121 Lecture 9.

Otorhinolaryngology

The branch of medicine that deals with the diagnosis and treatment of diseases of the ears, nose, and throat (ENT).

Pulmonologist

A medical doctor who specializes in the diagnosis and treatment of diseases of the lungs.

Physiological Dead Space

The volume of inspired air left in the respiratory passages that does not participate in gas exchange, accounting for approximately $30\%$ of a typical $500\,\text{mL}$ inhalation.

Conducting Zone

The series of interconnecting cavities and tubes—comprising the nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles—that filter, warm, and moisten air and conduct it into the lungs.

Respiratory Zone

The microscopic structural pathways of the lungs capable of gas exchange, including the respiratory bronchioles, alveolar ducts, alveolar saccules (sacs), and pulmonary alveoli.

Vomer

A thin, unpaired facial bone of the skull that forms the posteroinferior part of the nasal septum, separating the right and left nasal cavities.

Nasal Vestibule

The anterior entrance or opening of the nasal cavity, lined with skin containing hair follicles, sweat glands, and sebaceous glands to trap and filter out coarse dust particles.

Nasal Conchae

Three pairs of scroll-like bony projections (superior, middle, and inferior turbinates) on the lateral walls of the nasal cavity that swirl incoming air to promote warming, moistening, and filtering.

Internal Nares (Choanae)

The two posterior openings of the nasal cavity that communicate directly with the nasopharynx.

Pharynx

A funnel-shaped muscular tube extending from the internal nares to the cricoid cartilage that serves as a common passageway for air, food, and drink, provides a resonating chamber for speech, and houses protective tonsils.

Nasopharynx

The uppermost region of the pharynx, situated posterior to the nasal cavity and lined with ciliated pseudostratified columnar epithelium, which features $5$ openings and contains the pharyngeal tonsil.

Oropharynx

The intermediate division of the pharynx behind the oral cavity extending from the fauces to the hyoid bone, lined with nonkeratinized stratified squamous epithelium and containing the palatine and lingual tonsils.

Laryngopharynx

The lowermost region of the pharynx beginning at the level of the hyoid bone and opening into the esophagus posteriorly and the larynx anteriorly, lined with protective nonkeratinized stratified squamous epithelium.

Larynx

A short cartilaginous passageway (voice box) connecting the laryngopharynx to the trachea anterior to cervical vertebrae $\text{C4--C6}$, composed of a framework of $9$ cartilages.

Epiglottis

A large, leaf-shaped piece of elastic cartilage whose broad unattached leaf moves like a trap door to cover the glottis during swallowing, routing food and fluid toward the esophagus.

Thyroid Cartilage

The largest, shield-shaped cartilage of the larynx (often termed the Adam's apple), formed by two fusing laminae that protect the vocal cords and assist in maintaining their tension.

Cricoid Cartilage

A complete ring of hyaline cartilage forming the inferior wall of the larynx that serves as a primary anatomical landmark for emergency airway creation (cricothyrotomy).

Cricotracheal Ligament

The fibrous band of connective tissue attaching the inferior border of the cricoid cartilage to the first ring cartilage of the trachea.

Cricothyroid Ligament

The ligament that connects the thyroid cartilage to the cricoid cartilage of the larynx.

Arytenoid Cartilages

Paired, small, triangular segments of hyaline cartilage positioned at the posterosuperior border of the cricoid cartilage that influence changes in the position and tension of the vocal folds.

Corniculate Cartilages

Paired, horn-shaped pieces of elastic cartilage located at the apex of each arytenoid cartilage that serve as structural supports for the epiglottis.

Cuneiform Cartilages

Paired club-shaped elastic cartilages situated anterior to the corniculate cartilages that support the vocal folds and the lateral margins of the epiglottis.

Vestibular Folds

The superior pair of mucous membrane folds in the larynx (false vocal cords) that function in breath-holding and prevent foreign objects from entering the glottis.

Vocal Folds

The inferior mucous membrane folds in the larynx (true vocal cords) that vibrate to generate sound; they are thicker, longer, and vibrate more slowly in biological males due to androgen influence.

Rima Glottidis

The medial space or slit-like aperture located between the true vocal folds within the glottis.

Laryngitis

An inflammation of the larynx typically brought on by respiratory infection or environmental irritants, manifesting clinically as hoarseness or loss of voice.

Trachea

The tubular air passageway (windpipe) situated anterior to the esophagus, extending from the larynx to the superior border of vertebra $\text{T5}$, reinforced by $16\text{--}20$ incomplete C-shaped hyaline cartilage rings.

Trachealis Muscle

A bundle of transverse smooth muscle fibers and elastic connective tissue that bridges the posterior open ends of the C-shaped tracheal cartilage rings facing the esophagus.

Layers of the Tracheal Wall

The four structural layers of the trachea arranged from deep to superficial: respiratory mucosa, submucosa, hyaline cartilage layer, and adventitia.

Endotracheal Intubation

A procedure in which an endotracheal tube (ETT) is advanced through the mouth or nose into the larynx and trachea using a laryngoscope to secure an unobstructed airway and enable suctioning.

Tracheostomy

A surgical operation creating a cutaneous stoma into the trachea inferior to the cricoid cartilage to insert an airway tube, preferred for patients requiring prolonged mechanical ventilation.

Carina

An internal cartilaginous ridge situated at the bifurcation of the trachea into the right and left main bronchi; widening and distortion of its angle on X-ray indicates mediastinal malignancy or carcinoma.

Right Primary Bronchus

The main stem bronchus entering the right lung that is shorter, wider, and more vertical than the left, rendering it more prone to foreign body aspiration.

Secondary (Lobar) Bronchi

Branches of the primary bronchi that deliver air to the individual lung lobes, consisting of $3$ in the right lung and $2$ in the left lung for a total of $5$.

Tertiary (Segmental) Bronchi

Airway branches derived from secondary bronchi that each supply an individual bronchopulmonary segment, with $10$ present in each lung for a bilateral total of $20$.

Parietal Pleura

The superficial serous membrane layer that lines the inner surface of the thoracic wall, mediastinum, and superior surface of the diaphragm.

Visceral Pleura

The deep serous membrane layer that adheres closely to the external surface of the lungs and extends into the interlobar fissures.

Pleural Cavity

The small potential space enclosed between the parietal and visceral pleurae containing a small volume of lubricating serous fluid that minimizes friction during breathing.

Pleuritis (Pleurisy)

Inflammation of the pleural membranes surrounding the lungs and lining the thoracic wall.

Pleural Effusion

The abnormal collection and accumulation of fluid within the pleural cavity, commonly arising from persistent pleural inflammation or mediastinal cancer.

Pneumothorax

The abnormal presence of air or gas within the pleural cavity causing an increase in intrapleural pressure that precipitates partial or complete collapse of the affected lung.

Hemothorax

The accumulation of blood inside the pleural cavity, which can compress thoracic organs and induce obstructive shock.

Thoracentesis

An emergency medical procedure where a needle or chest tube is inserted anteriorly through the $\text{7th}$ intercostal space (ICS) to evacuate excess air or fluid from the pleural space.

Cardiac Notch

An indentation on the anteroinferior medial aspect of the left lung that accommodates the apex of the heart.

Hilum

A designated opening on the mediastinal surface of each lung through which bronchi, pulmonary blood vessels, lymphatic vessels, and autonomic nerves pass.

Bronchopulmonary Segment

An autonomous structural and functional lung unit enveloped in connective tissue septa that is supplied by an individual tertiary (segmental) bronchus.

Pulmonary Lobule

A small, pyramid-shaped compartment of a bronchopulmonary segment wrapped in elastic tissue, containing a lymphatic vessel, arteriole, venule, and terminal bronchiole branch.

Terminal Bronchiole

The final conducting airway segment lined by nonciliated simple cuboidal epithelium, marking the end of the non-gas-exchanging conducting zone.

Respiratory Bronchiole

A microscopic branch arising from a terminal bronchiole that contains alveoli protruding from its walls, signifying the start of the respiratory zone and gas exchange.

Alveoli

Microscopic balloon-like air sacs numbering approximately $300\times 10^6$ with an aggregate surface area of $70\,\text{m}^2$, serving as the primary sites of pulmonary gas exchange.

Alveolar Sac

A terminal cluster of two or more pulmonary alveoli that share a common entrance from an alveolar duct.

Type I Alveolar Cells

Predominant, thin, squamous epithelial cells that line the alveolar wall and form the principal cellular component of the air-blood barrier across which gas diffusion occurs.

Type II Alveolar Cells (Septal Cells)

Cuboidal epithelial cells interspersed among type I cells that secrete alveolar fluid containing pulmonary surfactant to decrease alveolar surface tension.

Pulmonary Surfactant

A phospholipid-rich secretory mixture that decreases the surface tension of alveolar fluid, preventing atelectasis (alveolar collapse) upon exhalation.

Dust Cells (Alveolar Macrophages)

Specialized wandering phagocytes located within the alveolar spaces that engulf and remove fine inhaled particulate matter, debris, and microorganisms.

Respiratory Membrane

The four-layer diffusion barrier through which alveolar gas exchange occurs, composed of the alveolar wall, epithelial basement membrane, capillary basement membrane, and capillary endothelial cells.