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.

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.

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

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.

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

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

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

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.