Respiratory System Overview

Respiratory System Overview

• The respiratory system is responsible for gas exchange between air and blood, as well as conditioning the air.
• It also plays a role in sound production and olfaction.

Upper Respiratory Tract

• The upper respiratory tract begins with the nasal cavity, which conducts air.
• The nasal cavity is composed of bone and cartilage.
• Nostril openings lead into the nasal cavity.
• The nasal cavity connects to the nasopharynx.
• The nasal cavity includes the nasal conchae, and meatuses, which warm, filter, and moisten air.
• Vibrissae are coarse hairs that trap particles.
• The nasal cavity is continuous with the nasopharynx, through internal nares.
• The vestibule is the anterior region.

Paranasal Sinuses

• Paranasal sinuses are cavities within the skull bones (frontal, ethmoid, sphenoid, and maxillary).
• They decrease the weight of the skull.
• They warm and moisten air and are connected to the nasal cavity.

Pharynx

• The pharynx is a shared passageway for the respiratory and digestive systems.
• It begins behind the nasal and oral cavities and ends at the splitting of the larynx and esophagus.
• There are three regions: nasopharynx, oropharynx, and laryngopharynx.

Choanae

• Choanae are the entryway to the nasopharynx from the nasal cavity, used only by the respiratory system.
• The soft palate and uvula prevent swallowed material from entering the nasal cavity.

Internal Structures of Nasal Cavity

• The nasal cavity is continuous with the nasopharynx.
• The vestibule is the anterior region of the nasal cavity.

Internal Structures of Nasal Cavity (continued)

• The nasal cavity, including the nasal conchae, are continuous with the nasopharynx through internal nares.
• The vestibule is the anterior region, near the nostrils.

Trachea

• The trachea is anterior to the esophagus, inferior to the larynx, and superior to the primary bronchi.
• It has 15-20 C-shaped cartilages that keep the trachea open.
• The trachea has an anular ligament that connects the C-shaped cartilages.
• The trachealis muscle covers the open ends of the C-shaped cartilages; its contraction and relaxation alter the diameter of the trachea.

Primary Bronchi

• The trachea branches into the right and left primary bronchi at the sternal angle.
• The right primary bronchus is shorter, wider, and more vertical, which explains why foreign matter is more likely to lodge in the right lung.
• Carina is the inferiomost tracheal cartilage.

Bronchial Tree

• The bronchial tree is a system of branching tubes that originate from the primary bronchi.
• The tubes progressively divide throughout the lungs.
• The tubes end in terminal bronchioles.

Bronchioles

• Bronchioles are tubes with diameters of less than 1 mm.
• Terminal bronchioles continue to branch before ending as terminal bronchioles.

Respiratory Zone

• The respiratory bronchioles branch off terminal bronchioles.
• The respiratory zone is the site of gas exchange. This is where terminal bronchioles branch into respiratory bronchioles which in turn branch into even smaller respiratory bronchioles.
• Alveolar ducts and alveolar sacs are part of the respiratory zone.
• Alveoli are tiny sacs where gas exchange occurs.

Alveoli

• Alveoli are outpockets on the respiratory bronchioles, alveolar ducts and alveolar sacs.
• They are very thin and consist of a single layer of epithelial cells.
• There are numerous alveolar pores connecting adjacent alveoli for collateral ventilation.

Respiratory Membrane

• The respiratory membrane consists of the alveolar wall and juxtaposed capillaries.
• Gases must cross the respiratory membrane for gas exchange.

Lungs

• The lungs house the bronchial tree and respiratory zone.
• There are 2 lungs, separated by the mediastinum.
• The pleura covers the surface of the lungs and lines the lung chamber (parietal pleura and visceral pleura).
• The pleural cavity contains pleural fluid.

Surfaces of the Lungs

• The lung surfaces include the costal (exterior) and mediastinal (medial) surfaces.
• The hilum (on the mediastinal surface) is where structures like bronchi, blood vessels, and nerves enter and leave the lungs.

Right vs Left Lung

• The left lung is slightly smaller than the right due to the heart's position in the mediastinum.
• The left lung has two lobes separated by an oblique fissure.

Left Lung

• The left lung has a cardiac impression on the mediastinal surface.
• There's a cardiac notch.
• The left lung consists of superior and inferior parts separated by an oblique fissure.

Clinical Conditions

• Chronic bronchitis, asthma, and tuberculosis are respiratory diseases; common symptoms are inflammation of the lungs.
• Pneumonia is caused by bacterial, viral, or fungal infection.
• Emphysema is a form of COPD, characterized by alveolar wall breakdown.
• Lung cancers (squamous cell carcinoma, adenocarcinoma, and small cell carcinoma).

This quiz explores the fundamental aspects of the respiratory system, including its structure and functions. It delves into the upper respiratory tract and the role of paranasal sinuses in air conditioning and filtration. Test your knowledge of key components such as the nasal cavity and pharynx.