Anatomy WK 7 (3/18) | Respiratory System Overview

Respiratory Mucosa

• The respiratory mucosa is present throughout the airways, beginning in the nose.
• The epithelial lining is primarily composed of ciliated pseudostratified columnar epithelium.
  • Cilia Purpose: Cilia aid in moving mucus along the membrane, crucial for keeping airways clear.
• Goblet Cells: Secrete mucus, which is then moved by cilia, preventing accumulation in alveoli.

Mucus and Rhinitis

• Mucus helps trap particles and pathogens, and it is moved towards the throat for swallowing or expulsion.
• Excessive mucus can lead to conditions like rhinitis, defined as inflammation of nasal mucosa.
  • Symptoms: Runny nose, caused by irritants (allergens, infections).
• Inflammation leads to:
  • Increased blood flow and capillary permeability, causing swelling and thickening of the mucosa.
  • Resulting in more mucus production, which can clog airways.

Treatment Options for Runny Nose

• Pseudoephedrine (Sudafed):
  • Commonly prescribed nasal decongestant, functioning as a stimulant and vasoconstrictor.
  • Reduces blood flow and capillary leakiness in mucosa, thus decreasing mucus production and inflammation.
• Caution: Not suitable for individuals with high blood pressure due to its vasoconstrictive effects.
• Alternative decongestants exist for patients with high blood pressure.

Nasal Cavity and Its Functions

• The nasal cavity serves several purposes:
  • Olfaction: Ability to smell due to olfactory mucosa.
  • Air Conditioning: Warm air to body temperature and add moisture before reaching the lungs.
  • Mucosal Contact: Increased surface area for air contact through nasal turbinates (conchae).

Sinuses

• Sinuses are hollow spaces connected to the nasal cavity, facilitating air flow and mucosal contact, but can become inflamed (sinusitis).
• Sinusitis: Inflammation leads to blockage of narrow sinus openings, causing pressure and pain.
  • Treatments include medications and surgeries (e.g., balloon sinoplasty) to reduce obstruction and improve drainage.

Pharynx

• The pharynx connects the nasal cavity to the mouth and is divided into three sections:
  • Nasopharynx: Superior section, above the soft palate.
  • Oropharynx: Intermediate section, behind the oral cavity.
  • Laryngopharynx (Hypopharynx): Inferior section, leading to the larynx.
• Function: Both air and food pass through these sections, highlighting the need for structures like the epiglottis to prevent aspiration.

Tonsils

• Tonsils are lymphoid tissues located in the pharynx, playing a role in immune response.
  • Three types: Pharyngeal (adenoids), palatine, and lingual tonsils.
• Function: Act as a frontline defense against pathogens by producing white blood cells.
• Chronic Inflammation: Swollen tonsils requiring treatment may be managed with medications, reducing the need for surgical removal, especially in children.

Larynx

• The larynx, or voice box, is composed of various cartilages and connects the pharynx to the trachea.
• Structures include:
  • Epiglottis: Prevents food and liquid from entering the trachea during swallowing.
  • Vocal Cords: Located within the larynx, they vibrate to produce sound.
  • Glottis: The space between vocal cords that varies in size based on cord positioning.

Trachea

• A flexible tube made of c-shaped rings of cartilage that carries air from the larynx to the lungs.
  • Structure: Rings provide support and prevent collapse while allowing flexibility.
  • Contraction of Back Muscles: Facilitates adjustments during respiratory distress (
  • e.g., during asthma attacks).

Conclusion

• Understanding the structure and function of the respiratory system, including the mucosa, sinus, pharynx, tonsils, larynx, and trachea, is fundamental for grasping respiratory health and potential medical conditions.