The structure and function of the nose are central to respiratory physiology, olfaction, and intranasal drug delivery — essential topics for B. Pharm students. This introduction reviews nasal anatomy (external nose, nasal cavity, turbinates, septum), histology (respiratory and olfactory mucosa, ciliated epithelium, goblet cells), physiological roles (air conditioning, filtration, mucociliary clearance, smell), and clinical and pharmaceutical relevance (nasal blood supply, lymphatics, mucosa permeability, intranasal absorption and systemic delivery). Understanding nasal barriers, local enzymes, and paranasal sinuses informs formulation, dosing and delivery strategies. Grasping structure-function relationships helps predict drug pharmacokinetics and therapeutic outcomes. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which epithelial type primarily lines most of the nasal cavity involved in air filtration and mucociliary clearance?
- Pseudostratified ciliated columnar epithelium with goblet cells
- Simple squamous epithelium
- Stratified squamous keratinized epithelium
- Transitional epithelium
Correct Answer: Pseudostratified ciliated columnar epithelium with goblet cells
Q2. The olfactory region of the nasal mucosa is characterized by which specialized cell type?
- Olfactory receptor neurons
- Type I pneumocytes
- Goblet cells
- Brush cells
Correct Answer: Olfactory receptor neurons
Q3. Which nasal structure increases the surface area for warming and humidifying inspired air?
- Inferior, middle and superior turbinates (conchae)
- Nasal vestibule
- Hard palate
- Pharyngeal tonsil
Correct Answer: Inferior, middle and superior turbinates (conchae)
Q4. What is the primary mechanism by which the nose clears inhaled particles and pathogens?
- Mucociliary clearance driven by coordinated ciliary beating
- Phagocytosis by alveolar macrophages
- Antibody secretion by salivary glands
- Mechanical filtration by nasal hair only
Correct Answer: Mucociliary clearance driven by coordinated ciliary beating
Q5. Kiesselbach’s plexus (Little’s area) is clinically important because it is a common site of:
- Anterior epistaxis (nosebleed)
- Sinus infection drainage obstruction
- Olfactory loss
- Posterior epistaxis from sphenopalatine artery
Correct Answer: Anterior epistaxis (nosebleed)
Q6. Which artery is the main contributor to the posterior nasal blood supply relevant to severe epistaxis?
- Sphenopalatine artery
- Anterior ethmoidal artery
- Facial artery
- Superior labial artery
Correct Answer: Sphenopalatine artery
Q7. Intranasal drug delivery can achieve rapid systemic absorption because the nasal mucosa has:
- Rich vascularization and large surface area
- Low enzyme activity compared with the intestine
- Keratinized epithelium that facilitates diffusion
- High lymphatic drainage only in the vestibule
Correct Answer: Rich vascularization and large surface area
Q8. Which factor most decreases intranasal drug absorption?
- Large molecular size and low lipophilicity
- Presence of absorption enhancers
- High mucosal blood flow
- Optimal droplet particle size (10–50 µm)
Correct Answer: Large molecular size and low lipophilicity
Q9. The main barrier to paracellular drug transport across nasal epithelium is:
- Tight junctions between epithelial cells
- Lamina propria collagen fibers
- Ciliated cell microvilli
- Mucous gel viscosity alone
Correct Answer: Tight junctions between epithelial cells
Q10. Which nasal enzyme class is most relevant for metabolizing peptide drugs delivered intranasally?
- Peptidases/proteases in the nasal mucosa
- CYP450 enzymes
- Amylases
- Lipases
Correct Answer: Peptidases/proteases in the nasal mucosa
Q11. The opening that connects the nasal cavity to the nasopharynx is called the:
- Choana
- Ostium
- Fornix
- Meatus
Correct Answer: Choana
Q12. Which paranasal sinus is located above the orbit and drains into the middle meatus?
- Frontal sinus
- Maxillary sinus
- Sphenoidal sinus
- Ethmoidal air cells
Correct Answer: Frontal sinus
Q13. Ciliary beat frequency and mucociliary clearance are reduced by which condition commonly affecting nasal drug delivery?
- Smoking
- Hydration of mucosa
- Humidified air exposure
- Use of isotonic saline
Correct Answer: Smoking
Q14. Which transport route is most important for lipophilic small molecules across nasal epithelium?
- Transcellular passive diffusion
- Paracellular aqueous pathway
- Endocytosis into goblet cells
- Transport via tight junctions
Correct Answer: Transcellular passive diffusion
Q15. A common formulation strategy to increase residence time of intranasal drugs is to use:
- Mucoadhesive polymers (e.g., chitosan)
- Hydrophobic oils only
- High-concentration ethanol
- Small volatile solvents
Correct Answer: Mucoadhesive polymers (e.g., chitosan)
Q16. Which nerve provides primary sensory innervation to the anterior nasal septum and lateral wall?
- Ophthalmic (V1) and maxillary (V2) branches of trigeminal nerve
- Facial nerve (VII)
- Glossopharyngeal nerve (IX)
- Hypoglossal nerve (XII)
Correct Answer: Ophthalmic (V1) and maxillary (V2) branches of trigeminal nerve
Q17. The nasal mucosa contributes to innate immunity primarily through:
- Mucus with antimicrobial peptides and IgA
- Systemic IgG secretion only
- Keratin production
- Secretion of bile salts
Correct Answer: Mucus with antimicrobial peptides and IgA
Q18. Which of the following best describes the vestibule of the nose?
- Keratinized stratified squamous epithelium containing nasal hairs
- Olfactory epithelium with receptor neurons
- Highly vascular respiratory mucosa
- Site of paranasal sinus openings
Correct Answer: Keratinized stratified squamous epithelium containing nasal hairs
Q19. Particle size for nasal sprays intended for local deposition should ideally be in which range?
- 10–100 µm to deposit in the nasal cavity
- <1 µm to reach alveoli
- 500–1000 µm for optimal coverage
- 0.1–0.5 mm to avoid mucosal contact
Correct Answer: 10–100 µm to deposit in the nasal cavity
Q20. One major limitation of intranasal delivery for large proteins is:
- Enzymatic degradation by nasal peptidases
- Excessive lipophilicity of proteins
- Complete lack of vascular supply
- Absence of lymphatic drainage
Correct Answer: Enzymatic degradation by nasal peptidases
Q21. Which histologic feature distinguishes respiratory from olfactory mucosa?
- Presence of olfactory receptor neurons and sustentacular cells
- Presence of goblet cells only in olfactory mucosa
- Keratinized surface layer in olfactory mucosa
- Lack of vascular plexus in olfactory mucosa
Correct Answer: Presence of olfactory receptor neurons and sustentacular cells
Q22. Nasal lymphatic drainage is important for vaccine delivery because it:
- Facilitates antigen transport to regional lymph nodes
- Prevents any immune recognition of antigens
- Removes only red blood cells
- Increases mucociliary clearance rate exclusively
Correct Answer: Facilitates antigen transport to regional lymph nodes
Q23. Which physiological property of nasal mucus affects drug diffusion the most?
- Mucus viscosity and mesh size of mucin network
- Mucus color
- Mucus temperature only
- Mucus electrical conductivity
Correct Answer: Mucus viscosity and mesh size of mucin network
Q24. Vasoconstrictor nasal sprays (e.g., phenylephrine) improve nasal patency by acting on:
- Alpha-adrenergic receptors in nasal mucosal blood vessels
- Beta-adrenergic receptors in olfactory neurons
- Muscarinic receptors on goblet cells
- Dopamine receptors in the septal cartilage
Correct Answer: Alpha-adrenergic receptors in nasal mucosal blood vessels
Q25. The major venous plexus involved in the erectile function of the nasal mucosa is the:
- Sphenopalatine and cavernous venous plexus (nasal erectile tissue)
- External jugular vein
- Superior vena cava
- Inferior alveolar plexus
Correct Answer: Sphenopalatine and cavernous venous plexus (nasal erectile tissue)
Q26. Which statement about nasal pH is most relevant for drug formulation?
- Nasal pH (~5.5–6.5) influences drug ionization and absorption
- Nasal pH is uniformly alkaline (>8.0) across individuals
- Nasal pH does not affect peptide stability
- Nasal pH is identical to gastric pH
Correct Answer: Nasal pH (~5.5–6.5) influences drug ionization and absorption
Q27. Tight junction modulators (absorption enhancers) can increase nasal uptake by:
- Reversibly opening paracellular pathways
- Destroying cilia permanently
- Increasing mucous production only
- Blocking blood flow to the nasal mucosa
Correct Answer: Reversibly opening paracellular pathways
Q28. Which clinical condition directly impairs mucociliary clearance and commonly affects nasal drug effectiveness?
- Chronic rhinosinusitis with ciliary dysfunction
- Hypertension without nasal involvement
- Myopia
- Osteoarthritis of the knee
Correct Answer: Chronic rhinosinusitis with ciliary dysfunction
Q29. For targeting the olfactory region for nose-to-brain delivery, formulations must reach which nasal area?
- Superior nasal meatus and upper posterior septum
- Anterior vestibule only
- Inferior meatus exclusively
- External naris skin surface
Correct Answer: Superior nasal meatus and upper posterior septum
Q30. Which strategy reduces systemic exposure of a locally acting nasal corticosteroid?
- Use of low systemic bioavailability molecule and targeted intranasal delivery
- Increasing systemic absorption enhancers
- Administering large oral doses concurrently
- Formulating with high ethanol content to increase permeability
Correct Answer: Use of low systemic bioavailability molecule and targeted intranasal delivery
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
Mail- Sachin@pharmacyfreak.com