Chapter 11.1

Big Picture – Purpose & Functions of the Respiratory System

  • Supplies O<em>2O<em>2 to body; removes CO</em>2CO</em>2

    • Gas exchange site: alveoli (microscopic air-sacs covered by capillaries)

  • Produces sound via larynx (voice box)

  • Assists in acid–base balance (removal of acidic CO2CO_2)

Anatomical Road Map (Superior ➜ Inferior)

  • Upper Respiratory Tract

    • Nose / Nasal cavity

    • Septum (cartilage + bone) separates cavities

    • Cilia & mucus (muco-) trap debris

    • Paranasal sinuses lighten bone & resonate sound ➜ susceptible to sinusitis

    • Combining forms: nasal-, rhino-, septo-, sinuso-, muco-

    • Example: rhinitis=rhino+itis\text{rhinitis} = \text{rhino} + itis (inflammation of nose)

    • Pharynx (throat)

    • Sections: nasopharynx, oropharynx, laryngopharynx

    • Combining form: pharyngo- (plural form base –g-)

    • Plural: pharynx → pharynges

    • Tonsillar tissue

      • Adenoids (pharyngeal tonsils) – adenoido-

      • Palatine tonsils – tonsillo- (note double "l" in combining form)

  • Transition Structure

    • Larynx (voice box) – laryngo-

    • Cartilaginous; largest piece = thyroid cartilage (Adam’s apple / laryngeal prominence)

    • Epiglottis (epi-glotto) guard flap; glottis = space between vocal folds

    • Vocal folds vibrate ➜ phonation (phono-)

    • Pathologies: laryngitis, laryngospasm, epiglottitis

  • Lower Respiratory Tract

    • Trachea (windpipe) – tracheo-

    • C-shaped cartilage rings

    • Carina: last tracheal ridge; strong cough reflex / tracheal bifurcation

    • Bronchi (bronchus sing.) – broncho-, bronchio-

    • Main/primary ➜ secondary ➜ tertiary ➜ bronchioles (-ole = small)

    • ~2323 generations of branching

    • Alveoli (alveolus sing.) – alveolo-

    • Hundreds of millions/lung; actual site of external–internal gas exchange

    • Lungs (pulmono-, pneumo-/pneumono-/pneumato-)

    • Right lung: 3 lobes (superior, middle, inferior)

    • Left lung: 2 lobes + cardiac notch

    • Lobo- (lobe); adjective form lobar

    • Mediastinum = central thoracic compartment (heart, great vessels, trachea, esophagus, thymus); combining form mediastino-

  • Supporting Structures

    • Pleura (serous membrane surrounding each lung) – pleuro-

    • Visceral layer (covers lung) vs. parietal layer (lines chest wall)

    • Pleural cavity: thin fluid layer; pressure << atmospheric ⇢ keeps lungs inflated

    • Diaphragm (phrenic muscle) – diaphragmatico-, phren-/phrenno-

    • Skeletal, dome-shaped; primary muscle of inspiration

    • Also assisted by intercostal muscles (between ribs; costo-)

Physiology Highlights

  • Ventilation (external respiration)

    • Inspiration (inhalation) a.k.a. inspiration

    • Diaphragm contracts ↓, intercostals lift ribs → thoracic volume ↑, intrapulmonary pressure ↓, air flows in

    • Expiration (exhalation) a.k.a. expiration

    • Opposite muscle actions → volume ↓, pressure ↑, air out

  • Internal Respiration: diffusion of O<em>2/CO</em>2O<em>2/CO</em>2 between capillary blood & tissues

Foundational Combining Forms – Quick Reference

  • Air/breath: aspiro- (suck in), spiro- (breathe)

  • Oxygen: oxo-, oxa-

  • Carbon dioxide: capno-, capni-

  • Chest/thorax: thoraco-, pectoro-

  • Rib: costo-

  • Lung/air: pneumo-/pneumato-/pneumono-; lung only: pulmono-

  • Incomplete: atelo- (not tel-!)

  • Sound/voice: phono-

  • Listen: ausculto- (osculato-)

Prefix & Suffix Toolkit (most common for resp.)

  • Prefixes:

    • in-/im-/en- →\rightarrow in, into

    • eu- (good/normal), hypo- (below), hyper- (above/excessive), tachy- (fast), pan- (all)

  • Suffixes:

    • ‑pnea (breathing): e.g. apnea\text{apnea}, dyspnea\text{dyspnea}

    • ‑cele (herniation)

    • ‑centesis (puncture to aspirate)

    • ‑ectasis (dilation/stretch)

    • ‑itis (inflammation)

    • ‑spasm (involuntary contraction)

    • ‑plasty (surgical repair)

    • ‑emia (in the blood)

    • ‑oxia (oxygen condition)

Representative Terminology & Clinical Conditions

Breathing Patterns & Symptoms

  • Eupnea = normal breathing

  • Apnea = temporary cessation of breathing (sleep apnea)

  • Dyspnea = difficult/labored breathing

  • Orthopnea = discomfort when lying flat; relieved by sitting up

  • Tachypnea = rapid respiratory rate

  • Hyperpnea = increased rate and depth

  • Cheyne–Stokes respirations: cyclic apnea ↔ deep rapid breaths (seen in brain injury/end-of-life)

  • Patent airway = open, unobstructed

Nose / Upper Tract Disorders

  • Epistaxis = nosebleed

  • Rhinitis, sinusitis, pansinusitis (pan- all sinuses)

  • Pharyngitis vs. nasopharyngitis

  • Tonsillitis / adenoiditis; tonsillectomy

Laryngeal & Tracheal Issues

  • Laryngitis (often hoarseness/aphonia)

  • Laryngospasm (involuntary closure → airway emergency)

  • Epiglottitis (rapid swelling; pediatric airway risk)

Pulmonary Mechanics & Pleural Pathologies

  • Atelectasis = collapsed lung (atelo- + ectasis → “incomplete expansion”)

    • Often secondary to pneumothorax

  • Pneumothorax = air in pleural cavity

  • Hemothorax = blood in pleural cavity

  • Pleural effusion = fluid accumulation (can be serous, blood, pus)

  • Pleuritis / pleurisy = inflamed pleura (pleuritic pain with breathing)

  • Diaphragmatocele (congenital diaphragmatic hernia) – abdominal organs protrude into thorax → neonatal respiratory distress

Vascular Complications

  • Pulmonary embolism = traveling clot (embolus) lodged in pulmonary artery → infarction risk

  • Hypoxemia (low O<em>2O<em>2 in blood) vs. Hypoxia (low O</em>2O</em>2 in tissues); Anoxia = none

Infectious Diseases

  • Influenza (viral) – potential to progress to viral or secondary bacterial pneumonia

  • Pertussis (Bordetella pertussis) a.k.a. whooping cough – vaccine preventable (Tdap)

  • Pneumonia (condition of fluid-filled alveoli)

    • Bacterial, viral, fungal, aspiration variants

    • Bronchopneumonia (patchy), lobar pneumonia (entire lobe), pneumococcal pneumonia (Streptococcus pneumoniae)

  • Tuberculosis (Mycobacterium tuberculosis)

    • Formation of cavitating tubercles; may disseminate (extrapulmonary TB)

    • Public-health significance, drug resistance ethical concern

  • Empyema = collection of pus in pleural space (aka pyothorax)

Chronic & Fibrotic Conditions

  • Pulmonary edema = fluid in interstitium/alveoli (often cardiogenic from left-heart failure)

  • Pulmonary fibrosis / Interstitial Lung Disease (ILD) = replacement of elastic lung tissue with stiff fibrotic tissue ➜ “stiff lung,” ↓ ventilation compliance

Diagnostic & Therapeutic Concepts (Connections to Procedures)

  • Auscultation of breath sounds (crackles, wheezes) – links to cardiovascular auscultation skills

  • Sputum culture & staining (e.g., acid-fast for TB) – microbiology crossover

  • Spirometry (spiro-) to measure FEV, vital capacity; distinguishes obstructive vs. restrictive (IL D) patterns

  • Thoracentesis (pleural tap) – uses ‑centesis suffix to relieve effusion/pneumothorax

  • Chest tube insertion to re-establish negative pleural pressure

  • Vaccination ethics: herd immunity for pertussis, influenza; drug-resistant TB global health implication

Helpful Example Word Constructions

  • Hyper+pnea→hyperpnea\text{Hyper} + \text{pnea} \rightarrow \text{hyperpnea} (fast/deep breathing)

  • Lobo+ar→lobar\text{Lobo} + ar \rightarrow \text{lobar} (pertaining to a lobe)

  • Pharyngo+itis→pharyngitis\text{Pharyngo} + itis \rightarrow \text{pharyngitis} (throat inflammation)

  • Diaphragmato+cele→diaphragmatocele\text{Diaphragmato} + cele \rightarrow \text{diaphragmatocele}

  • Pneumo+thorax→pneumothorax\text{Pneumo} + thorax \rightarrow \text{pneumothorax}

Cross-System / Real-World Connections

  • Lymphatic overlap: adenoids & tonsils are lymphoid tissue (immunity lecture tie-in)

  • Cardiovascular overlap: pulmonary embolism parallels coronary thrombosis; pulmonary edema secondary to left-sided heart failure

  • Public health & ethics: vaccination compliance (pertussis), antimicrobial stewardship (TB resistance)

  • Ergonomics: teaching patients diaphragmatic breathing and incentive-spirometer use post-surgery prevents atelectasis

Quick Numerical / Statistical Nuggets

  • Approx. 2323 airway branchings from trachea to alveolar sacs

  • Hundreds of millions of alveoli per lung → surface area ≈ 70 m2\text{70 m}^2 (tennis-court-sized)

  • Normal pleural cavity width ≈ 1−2 mm1{-}2\,\text{mm}; intra-pleural pressure ≈ −4-4 to −6 mmHg-6\,\text{mmHg} at rest (lower than atmospheric)

Study & Exam Tips

  • Memorize singular ↔ plural conversions (bronchus/bronchi, pharynx/pharynges, alveolus/alveoli, pleura/pleurae)

  • When spelling combining forms ending in –nx (laryn-, pharyn-): change x→gx \rightarrow g for easier pronunciation

  • Differentiate ventilation (air movement) vs. respiration (gas exchange) in essay questions

  • Build words from parts to decode unfamiliar terminology quickly on tests/clinical charts