Applied Anatomy and Physiology of the Nose

Outline of Applied Anatomy and Physiology of the Nose

I. Introduction

• Understanding the anatomy and physiology of the nose aids in comprehending rhinitis pathophysiology and pharmacotherapeutic approaches.

II. Functions of the Nose

• Smell

• Speech

• Conditioning of Inspired Air:

  • Warms, humidifies, and filters air for lung delivery.

III. External Anatomy

• Pyramidal shape composed of nasal bones and cartilage

• Nostrils (nares): Two elliptical-shaped openings

IV. Internal Anatomy

• Nasal Septum: Separates nasal cavity; made of bone and cartilage

• Conchae (Turbinates): Found in the lateral walls of the internal cavity; Bony projections which increase surface area and airflow turbulence

• Openings: Sinuses and eustachian tubes, lacrimal drainage ducts connect to the nasal cavity near the turbinates

V. Mucosal Membranes

• Epithelial Cells: Ciliated columnar cells with goblet cells for mucus

• Cilia: Transport mucus across the upper airway membrane to the nasopharynx, providing a defense barrier

• Immunoglobulin A (IgA): Contained in respiratory secretions of mucous membranes which acts as an immunologic defense

VI. Nervous Control

• Autonomic Nervous System: Regulates vascular supply and mucus secretion

  • Sympathetic Activation: Vasoconstriction, reducing nasal airway resistance

  • Parasympathetic Stimulation: Increases glandular secretion, causing nasal congestion

• Nonadrenergic-Noncholinergic (NANC) System: Innervates the mucosa; produces neuropeptides (substance P and neurokinins) which influence vasoditation, mucus production and inflammation

• Trigeminal Nerve: Provides sensory innervation causing sneezing and itching

VII. Airflow Dynamics

• Normal Breathing: Inspired air flows through the external nose into the nasopharynx and beyond

• Nasal Cycle: Alternating swelling of turbinates for preferential airflow

• Disruptions: Inflammation, congestion, and anatomical deformities like septal deviation impact airflow.