Respiratory System Overview

Respiratory System Overview

• Functions include pulmonary ventilation, external respiration, transport of respiratory gases, and internal respiration.
• Pulmonary ventilation: Movement of air in and out of the lungs.
• External respiration: Exchange of O2 from lungs to blood and CO2 from blood to lungs.
• Transport of respiratory gases is facilitated by the cardiovascular system using blood.
• Internal respiration: Transfer of O2 from blood to tissues and CO2 from tissues to blood.

Nose Structure

• Divided into the external nose (nostrils or nares) and the nasal cavity (posterior to the external nose).
• Functions:
  • Provides airway for respiration.
  • Moistens and warms inhaled air.
  • Filters and cleans inspired air.
  • Acts as a resonating chamber for speech.
  • Houses olfactory receptors.

Nasal Cavity

• Air enters through the nostrils and is divided by the nasal septum, comprised of the perpendicular plate of the ethmoid bone, vomer, and cartilage.

Pharynx

• Connects nasal cavity and mouth to the larynx and esophagus.
• Plays a crucial role in both respiratory and digestive pathways.

Larynx (Voice Box)

• Provides an open airway and directs food to the esophagus.
• Responsible for voice production.

Trachea (Wind Pipe)

• Lined with pseudostratified ciliated columnar epithelium and supported by C-shaped hyaline cartilage rings.
• The trachealis muscle allows for esophageal expansion.
• Functions as an air passageway and conditions incoming air.

Carina

• The expanded last tracheal cartilage, crucial for triggering cough reflex when foreign objects are detected.
• Serves as a bifurcation point for the trachea.

Bronchial Tree

• Transition point from conducting zone to respiratory zone structures.
• Comprised of right and left main bronchi, lobar bronchi, and segmental bronchi.

Bronchioles

• Smaller than 1 mm in diameter, leading to terminal bronchioles (end of conducting zone) and respiratory bronchioles (beginning of respiratory zone).

Alveoli

• Composed of simple squamous epithelium, providing a large surface area for gas exchange.

Lungs

• Occupy most of the thoracic cavity, located within the pleural cavity.

Upper Respiratory System Structures

• Nasal Bones: Form the bridge of the nose.
• Nostrils (Naes): Entry point for air into the nasal cavity.
• Posterior Nasal Aperture (Choanae): Connects the nasal cavity to the nasopharynx.
• Olfactory Epithelium: Located in the roof of the nasal cavity, enhances sense of smell.
• Ethmoid Bone: Separates the nasal cavity from the brain.
• Frontal Bone: Makes up the forehead region.
• Frontal Sinus: Air-filled cavities within the frontal bone.
• Sphenoid Bone: Butterfly-shaped, articulates with all cranial bones.
• Sphenoid Sinus: Contains the pituitary gland resting on top.
• Maxillary Bone: Forms the upper jaw and parts of the hard palate and nasal cavity walls.
• Palatine Bone: Composes the posterior part of the hard palate.
• Hard Palate: Formed by the maxillary and palatine bones, creates the roof of the mouth.
• Soft Palate: Tissue at the back of the roof of the mouth, closes the nasopharynx during swallowing.
• Uvula: Small tissue mass that also closes the nasopharynx during swallowing.
• Nasal Conchae (Turbinates): Three mucosa-covered projections that enhance airflow dynamics and olfactory reception.
  • Superior Conchae: Heightens smelling capacity.
  • Middle Conchae: Positioned between superior and inferior.
  • Inferior Conchae: Largest conchae, separates inferior and middle meatuses of the nose.
• Nasal Meatus: Groove beneath each concha, facilitates drainage from sinuses and tears.