Respiratory Anatomy and Function Quiz

Respiratory Anatomy and Function

• The respiratory system conducts air to respiratory surfaces where oxygen and carbon dioxide are exchanged with the blood.
• It conditions the air, warming, humidifying, and cleaning it before reaching the respiratory tissues.
• The system plays a critical role in maintaining body pH.
• Secondary structures are involved in olfaction and vocalization.

Functional Zones

• The conducting zone conveys air between the external environment and respiratory surfaces.
• Lined with epithelial cells that secrete, filter, protect, and actively clear debris.
• Supported by muscle, bone, and cartilage.
• The respiratory zone is highly vascularized and perfused where gas exchange occurs.
• Contains thin, moist membranes without bony or cartilaginous support structures.

Structural Divisions

• Upper respiratory tract includes the nasal cavity, oral cavity, pharynx, and larynx.
• Important for warming and conditioning air.
• Lower respiratory tract includes the trachea and multiple generations of airways (bronchial tree).
• Proximal elements are cartilaginous, while distal ones are noncartilaginous.

Nasal Cavity

• Entry point for external air; anteriorly cartilaginous, posteriorly communicates with the pharynx.
• Paranasal sinuses are mucous membrane-lined spaces in the skull bones, linked to nasal cavity for humidification and warming, and voice resonance.
• Nasolacrimal ducts conduct tears to the nasal cavity from lacrimal glands.
• Auditory (Eustachian) tubes connect the middle ear to the posterior pharynx for equalizing air pressure.

Nasal Epithelium

• Respiratory pathways are exposed to the external environment requiring high turnover of epithelial tissues.
• Mucous, produced by specialized cells, moves posteriorly by cilia.

Functions of the Nasal Cavity

• Warms, humidifies, and cleans incoming air, trapping particles (dust, smoke, pollen).
• Conditions air for efficient gas exchange with respiratory membranes.

Olfaction and Phonation

• Olfactory receptors in the nasal cavity roof are crucial for smell.
• Air exhaled through the nose amplifies the voice's resonance.

Oral Cavity

• A secondary respiratory passage, clinically important in procedures like intubation.
• Embryological fusion failure of the maxillary bones results in cleft palate.
• Communication between nasal and oral cavities can occur.

Pharynx

• Nasopharynx (respiratory): continuous with posterior nasal cavity.
• Oropharynx (digestive/respiratory): spans between the soft palate and hyoid bone; houses tonsils.
• Laryngopharynx (lower respiratory): marks the transition to the larynx.

Larynx

• Adam's apple (thyroid cartilage) and epiglottis.
• Connects pharynx to the trachea, houses vocal cords.
• Critical for vocalization and preventing aspiration.

Lower Respiratory Tract

• Trachea is maintained by cartilage rings (incomplete posteriorly), is lined by ciliated respiratory epithelium.
• Conducts air to both lungs by bifurcating into right and left primary bronchi.

Tracheobronchial Tree

• Primary bronchi (C-shaped hyaline cartilage), Right shorter and wider than left.
• Secondary bronchi (connect to lung lobes), Different numbers on left and right sides.
• Tertiary bronchi (segmental), Supply bronchopulmonary segments in lungs.
• Bronchioles (noncartilaginous, <1 mm diameter), Supported by surrounding parenchyma.
• Terminal bronchioles, Loss of cilia and mucous cells, Decrease in epithelial thickness.
• Alveolar ducts & sacs are the beginning of the respiratory zone (very thin squamous epithelium for efficient gas exchange).

Alveoli

• 300 million alveoli in 130,000 acini in lungs.
• Structure is vital for efficient gas exchange.
• Extensive surface area for efficient gas exchange.

Alveolar Structure and Function

• Pulmonary capillaries form a dense network for gas exchange near the alveoli's surface.
• Surfactant-producing cells (Type II pneumocytes) coat alveoli to reduce surface tension and prevent collapse.

The Lung

• Lungs are divided into lobes (3 in the right, 2 in the left) separated by fissures.
• Pleura (double-membraned structure) surrounds each lung, reducing friction during ventilation.

Lung Surface and Lobes

• Right lung is slightly larger than left.
• Visceral and parietal pleura are connected in interlobar fissures.
• Lobes are associated with secondary bronchi (2/3 lobes based on secondary bronchi).

Bronchopulmonary Segments

• Lungs divided into segments, aligned with tertiary bronchi.

Test your knowledge on the anatomy and functions of the respiratory system, including its structural divisions and functional zones. Explore how the respiratory system conditions air, exchanges gases, and contributes to maintaining body pH. Assess your understanding of both the upper and lower respiratory tracts.