Respiratory System Part 1

Vocabulary flashcards covering anatomy, physiology, and pathology topics presented in the Respiratory System Part 1 lecture.

Respiratory System

Body system responsible for gas exchange, vocalization, olfaction, acid-base balance, immune defense, platelet production, blood filtration, and aiding abdominal expulsion.

Conducting Zone

Nasal cavity through larger bronchioles; cleanses, humidifies, and warms air but no gas exchange occurs.

Respiratory Zone

Smallest bronchioles and alveoli where actual gas exchange takes place.

Upper Respiratory System

Includes nose, nasal cavity, paranasal sinuses, and pharynx.

Lower Respiratory System

Includes larynx (below vocal cords), trachea, bronchi, bronchioles, and alveoli.

External Nares

External openings of the nose that admit air.

Nasal Vestibule

Anterior nasal “lobby” just inside external nares.

Nasal Septum

Partition separating left and right nasal cavities.

Nasal Conchae

Superior, middle, and inferior bony shelves creating turbulence to warm and filter air.

Meatuses

Passageways between conchae where air swirls; superior, middle, inferior.

Hard Palate

Bony anterior part of roof of mouth separating nasal and oral cavities.

Soft Palate

Muscular posterior roof of mouth that elevates during swallowing.

Internal Nares

Openings connecting nasal cavity to nasopharynx.

Respiratory Defense System

Mucus, lysozyme, defensins, cilia, and sneeze reflex that protect airways from pathogens and debris.

Mucociliary Escalator

Ciliary movement that propels mucus toward pharynx for swallowing.

Paranasal Sinuses

Frontal, sphenoidal, ethmoid, and maxillary cavities that lighten skull and warm/moisten air.

Epistaxis

Clinical term for a nosebleed.

Sinusitis

Inflammation of paranasal sinuses causing congestion, facial pain, and discolored discharge.

Pharynx

Muscular tube (nasopharynx, oropharynx, laryngopharynx) connecting nasal cavity and mouth to larynx and esophagus.

Nasopharynx

Superior pharyngeal region; air passage blocked by soft palate during swallowing.

Oropharynx

Middle pharyngeal region carrying food and air.

Laryngopharynx

Inferior pharyngeal region just above epiglottis; directs food and air to proper channels.

Pharyngitis

Inflammation of pharynx; sore throat often viral but can be bacterial.

Larynx

“Voice box” of cartilage; provides open airway, routes food/air, and houses vocal cords.

Thyroid Cartilage

Largest laryngeal cartilage forming the Adam’s apple.

Cricoid Cartilage

Ring-shaped laryngeal cartilage inferior to thyroid cartilage.

Epiglottis

Elastic cartilage flap that blocks laryngeal inlet during swallowing.

Glottis

Opening between vocal folds; wide for breathing, narrow when closed.

Epiglottitis

Acute, often H. influenzae type B-induced swelling of epiglottis causing airway obstruction (distress, drooling, dysphagia, dysphonia).

Tracheostomy

Emergency airway created by incising trachea below cricoid cartilage.

Trachea

“Windpipe”; 10–12 cm tube with 15–20 C-shaped cartilage rings and smooth-muscle trachealis.

Primary Bronchi

First branches of trachea; right is wider, shorter, more vertical than left.

Secondary (Lobar) Bronchi

Branch from primary bronchi; three on right, two on left, each serving one lung lobe.

Tertiary (Segmental) Bronchi

Branches supplying bronchopulmonary segments; continue dividing to 23rd order bronchi.

Bronchioles

Airways <1 mm with no cartilage but smooth muscle controlling diameter.

Terminal Bronchioles

Smallest conducting passages (<0.5 mm) leading to respiratory bronchioles.

Respiratory Bronchioles

First airways of respiratory zone; give rise to alveolar ducts and sacs.

Alveoli

Microscopic air sacs where gas exchange occurs.

Type I Pneumocytes

Simple squamous epithelial cells forming alveolar wall for diffusion.

Type II Pneumocytes

Cuboidal cells secreting surfactant to reduce surface tension.

Surfactant

Phospholipid-protein film that lowers alveolar surface tension, preventing collapse.

Respiratory Distress Syndrome

Condition in premature infants lacking surfactant leading to alveolar collapse.

Synthetic Surfactant Therapy

Intratracheal treatment improving outcomes and reducing mortality in preterm infants with RDS.

Surface Tension (Lungs)

Cohesive force of water lining alveoli; high tension collapses lungs unless reduced by surfactant.

Bronchodilation

Sympathetic β2-receptor-mediated relaxation of airway smooth muscle decreasing resistance.

Bronchoconstriction

Parasympathetic (M3) or histamine-mediated narrowing of bronchi increasing resistance.

Asthma

Allergic/hypersensitive airway disorder with bronchoconstriction, mucus, wheeze and dyspnea.

Albuterol

Short-acting β2 agonist inhaler causing rapid bronchodilation; may mildly raise heart rate.

Right Lung

Three lobes (superior, middle, inferior) and horizontal + oblique fissures.

Left Lung

Two lobes (superior, inferior) with cardiac notch and oblique fissure.

Acute Bronchitis

Inflammation of bronchi, usually viral; productive cough, rhonchi; rarely bacterial (Bordetella pertussis).

Acute Bronchiolitis

Viral inflammation of bronchioles, common in infants (RSV).

Pneumonia

Infection/inflammation of lungs; bacterial, viral, fungal, chemical; presents with fever, crackles, consolidation.

Aspiration Pneumonia

Lung injury from inhaled gastric contents (chemical) or oral microbes (bacterial), often affects right lower lobes.

Tuberculosis

Serious lower respiratory infection caused by Mycobacterium tuberculosis (lecture reference).

Valsalva Maneuver

Forceful expiration against closed glottis aiding defecation, urination, and childbirth.

Platelet Production in Lungs

50 % of megakaryocytes reside in lungs, releasing platelets into circulation.

Mucus

Viscous secretion with lysozyme and defensins trapping particles and microbes (~1 quart/day).

Defensins

Antimicrobial peptides secreted in respiratory mucus killing microbes.

Cilia

Hair-like projections moving mucus toward pharynx (mucociliary escalator).

Lysozyme

Enzyme in mucus that breaks down bacterial cell walls.