Nostril

A nostril is one of the two external openings of the nose through which air enters and leaves the nasal cavity. Each opening leads into a nasal passage that filters, warms, and humidifies inhaled air.

Nasal cavity: The hollow space inside the nose, extending from the nostrils to the throat. Each nostril opens directly into one side of this divided space.
Nasal breathing: The movement of air through the nasal passages during inhalation and exhalation. It is the ordinary airflow route through the nostrils.
Nasal obstruction: Partial or complete blockage of airflow through one or both nasal passages. Obstruction is often experienced as reduced airflow through a nostril.
Mouth breathing: Breathing in which air enters and leaves primarily through the mouth. It bypasses the nostrils and much of the nose’s air-conditioning function.
Nasal septum: A wall of cartilage and bone that separates the two sides of the nasal cavity. It divides the passageways reached through the left and right nostrils.
Nasal cycle: The alternating change in congestion between the two sides of the nose over time. It changes airflow resistance at each nostril without usually blocking both sides.
Deviated septum: A nasal septum displaced from the midline, sometimes narrowing one nasal passage. Septal displacement can make airflow through one nostril more difficult.
Stoma: A surgically created opening that connects an internal organ or cavity to the body surface. Unlike a natural nostril, a stoma is created surgically and may serve a different airway.
Nasal vestibule: The frontmost region of the nasal cavity, just inside each nostril. This short entry region contains coarse hairs that trap larger particles.
Olfaction: The sense of smell, produced when odor molecules activate receptors in the nasal cavity. Air entering the nostrils carries odor molecules toward the olfactory region.

Linked from 3 pages