Anatomy of the Respiratory System

Respiratory System Anatomy

• The respiratory system has upper and lower tracts.
• Upper tract structures conduct air to the lower tract.
• Gas exchange occurs in the lower tract structures.

Paranasal Sinuses

• Paranasal sinuses include frontal, sphenoid, ethmoid, and maxillary sinuses.
• The function of the paranasal sinuses was not explicitly mentioned, so it needs to be looked up if you need that information.

Pharynx

• The pharynx is divided into three regions: nasopharynx, oropharynx, and laryngopharynx.
• These structures are part of the airway pathways.

Oropharynx

• The oropharynx is lined with stratified squamous epithelium.
• It protects against abrasion.
• It's located posterior to the oral cavity.
• It opens into the mouth and includes tonsils.

Nasopharynx

• The nasopharynx originates at the base of the skull and extends to the soft palate.
• It opens into the eustachian tube (connecting to the middle ear).
• It is lined with ciliated epithelium and includes pharyngeal tonsils (adenoids).

Laryngopharynx

• The laryngopharynx connects the oropharynx to the esophagus.
• It lies inferior to the epiglottis and extends to the divergence of the larynx and esophagus.

Larynx

• The larynx is also known as the "voice box".
• It contains thyroid cartilage ("Adam's apple"), which maintains an open airway and protects vocal cords.
• Cricoid cartilage provides attachment for speech muscles
• Arytenoid cartilage supports vocal cord movement
• Cricothyroid ligament connects cricoid and thyroid cartilages
• Hyoid bone is U-shaped and allows broader tongue, pharyngeal, and laryngeal movements

Larynx: Additional Structure and Function

• Hyoid bone elevates during swallowing.
• Epiglottis closes off the larynx during swallowing to prevent unwanted materials
• Vestibular folds prevent food from entering the larynx
• Vocal folds produce sound from vibrations

Voice Box

• Vestibular folds are mucus membranes with ligaments that prevent food entering the larynx.
• Prevent air from leaving the lungs when holding breath

Vocal Folds/Vocal Cords

• They are mucus membranes folded over and stretched across the larynx.
• They are the primary source of voice production

Trachea

• The trachea has hyaline cartilage rings that maintain its open structure.
• It has pseudostratified ciliated columnar epithelium lining.
• The submucosa layer contains mucous glands.

Anatomy of the Lower Respiratory Tract

• The lower respiratory tract includes the trachea, bronchi, bronchioles, and alveoli.
• The trachea branches into two primary bronchi: one for each lung.
• Each primary bronchus branches into secondary bronchi.
• The bronchi branch into tertiary bronchi, bronchioles, and finally, alveoli.

Bronchial Pathway

• Right and left primary bronchi branch from the trachea.
• Primary bronchi lead to each lung
• The right primary bronchus is shorter and wider than the left.
• Primary branches into three secondary bronchi in the right lung and two in the left.
• Tertiary bronchi further branch leading to terminal bronchioles.
• Millions of alveoli form the terminal end, facilitating gas exchange.

Bronchial Pathways

• Trachea has pseudostratified ciliated columnar epithelium.
• Primary bronchi are lined with the same.
• Secondary bronchioles lack cartilage, with simple ciliated cuboidal epithelium.
• Terminal bronchioles have smooth muscle and no cartilage.

Bronchial Tree

• The right main bronchus is shorter, wider, and more vertical compared to the left.
• The right main bronchus enters the lung at T5, with three secondary bronchi.
• The left main bronchus is smaller, longer, and enters the lung at T6 with two secondary bronchi.

Respiratory Tubes and Alveoli

• Structure diagram with bronchioles, blood flow, and alveoli
• Functional description of alveoli with capillary network for gas exchange.

Alveoli

• Alveoli are the sites of gas exchange.
• They are in direct contact with capillaries in the lungs
• They ensure efficient exchange between the atmosphere and blood.

Alveolar Membrane Layers

• The membrane has alveolus-filled fluid
• Simple squamous epithelium lining
• Interstitial space (fluid filled)
• Capillaries, capillaries' endothelium basement membrane.

Alveolar Membrane

• 6 layers in the alveolar membrane: encrusted with pulmonary capillaries
• Alveolar wall (size of a tennis court) lined with flat epithelial cells (Type 1 cells making up 97%)
• Surfactant-producing Type 2 cells.
• Macrophages for immunity
• Water molecules.
• Surfactant Molecules.

Pleura (Lungs)

• Lungs are located in two cavities on either side of the heart, right with three lobes and left with two lobes.
• Lungs are encased in a sac called pleura.
• The right lung is nearly vertical, while the left lung has a cardiac notch.

Pleural Cavity

• Space between the visceral and parietal pleura, filled with fluid
• Provides lubrication and prevents lung collapse
• Prevents anatomical connection between the right and left lungs.

Pleural Space

• Visceral pleura cover the lungs, with associated blood vessels, bronchi, and nerves.
• Parietal pleura lines the chest wall, sensitive to pain, supplied by intercostal arteries.

Respiratory Muscles

• External intercostal muscles, internal intercostal muscles, and innermost intercostal muscles support respiration.

Volume Capacities

• Lab calculations for respiratory volumes and capacities

Define and Calculate Respiratory Volumes and Capacities

• Define resting tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume
• Calculation examples for functional residual volume, inspiratory capacity, vital capacity, and total lung capacity

Spirometer Data and Tracings

• Instrument to measure lung volumes and capacities
• Graphical representation of spirogram

Test your knowledge on the anatomy of the respiratory system, including its upper and lower tracts. Explore the structure and function of important components such as the pharynx and paranasal sinuses. This quiz covers key details about how these parts interact in air conduction and gas exchange.