Answer
Labels for Respiratory System Structures/Organs:
a. nasal cavity
b. nares (nose)
c. pharynx
d. epiglottis
e. glottis
f. larynx
g. trachea
h. bronchus
i. bronchioles
Work Step by Step
The nose is the first organ of the respiratory tract . It is also the main olfactory organ. The external nares ( sing. naris) or nostrils are the external openings into the nasal cavities-- the nasal cavities are separated by the septum. The nasal cavities also have two posterior openings--the choanae (sing. choanae)-- that empty into the nasopharynx.
The pharynx -- sometimes called the throat--connects the nasopharynx and the oropharynx with the
larynx by way of the laryngopharynx. a shared opening between digestive and respiratory system), through which air, food and water (drink) pass.
The larynx is a cartilaginous structure that contains the vocal cords, hence its other name , the voice box.
The larynx is usually open to allow air to pass into the trachea, but the esophagus, which is posterior to the trachea, is usually closed-- except during the process of swallowing. If the larynx opens during swallowing and food or drink slips into the trachea ( "wrong throat"), coughing is stimulated to dislodge the substance from the airway.
The glottis is the opening between the vocal cords of the larynx. The epiglottis is a flap of cartilage (covered with mucous membrane) located behind the tongue and attached anteriorly to the rim of the
larynx. The epiglottis projects upward except during swallowing when it folds over the larynx and facilitates the passage of food or drink across the opening of the respiratory tract and into the esophagus--usually without incident.
The trachea is the tube between the larynx and the primary bronchi. C-shaped rings of cartilage keep the trachea open for the passage of air to and from the lungs. These rings are open on the posterior side of the trachea where it is in contact withe the muscular esophagus. --this facilitates the expansion of the esophagus as food or drink is moved by peristaltic action into the stomach.
The trachea bifurcates close to the lungs to form the two primary bronchioles --right and left. The left bronchus trends almost at right angles to the trachea; the inner angle between the trachea and the right bronchus is smaller ( acute angle). The right lung has three lobes and the left lung has two. Each lobe has segments; therefore the bronchi branch repeatedly to supply all the pulmonary segments. As the bronchi get smaller, they are called bronchioles and the cartilaginous component becomes smaller until the ( cartilage "rings" disappear..The last/smallest tubes of the conducting part of the airways are the terminal bronchioles. These lead to the respiratory bronchioles --the first part of the respiratory part of the tract-- which lead to the alveolar ducts.
