Conducting portion transports air includes the nose

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Conducting portion- (transports air) includes the nose, nasal cavity, and the pharynx of the upper respiratory tract and the larynx, trachea, and progressively smaller airways of the lower respiratory tract. Respiratory portion- (where gas exchange with blood occurs) is composed of small airways called respiratory bronchioles and alveolar ducts as well as air sacs called alveoli in the lower respiratory tract. Respiratory System Functions Inhaling & Exhaling Gas Exchange- External respiration( the exchange of gases between the atmosphere and the blood). Internal respiration( the exchange of gases between the blood and the cells of the body.
Gas Conditioning- the gases are warmed to body temperature, humidified, and cleansed of particulate matter through contact with the respiratory epithelium and its sticky mucous covering. Facilitated by the twisted pathways through the nasal cavity and paranasal sinuses. Sound Production- When air is forced out of the lungs and moves through the larynx, sound may be produced, such as speech or singing. Olfaction- Sense of smell. The receptors are stimulated when airborne molecules are inhaled and dissolved in the mucus covering the olfactory epithelium. Defense- The nose is lined with coarse hairs, and has twisted passageways to prevent large particles, microorganisms, and insects fro entering. Mucous glands also secrete lysozyme , an enzyme that helps defend against inhaled bacteria. The layer of sticky mucus traps inhaled dust, dirt particles, microorganisms, and pollen. 25.2 Nose and Nasal Cavity The nose is the main conducting airway for inhaled air and is supported superiorly by paired nasal bones that form the bridge of the nose. The frontal bone, nasal bones, cribriform plate of the ethmoid, and sphenoid bone form the roof of the nasal cavity. The palatine process of the maxillae and the horizontal plate of the palatine bones form the floor of the nasal cavity. Vestibule- the anterior region of the nasal cavity, near the nostrils. Vibrissae- coarse hairs that help trap lager particles before they pass through the nasal cavity. ( Near the vestibules)
3 paired bony projections- superior, middle, and inferior nasal conchae- they subdivide the nasal cavity into separate air passages called nasal meatus. Superior, middle, and inferior nasal meatuses correspond to its nasal conchae. As inhaled air passes over constricted, narrow grooves in each meatus, the inhaled air becomes turbulent. Increased turbulence ensures that the air remains in the nasal cavity for a longer time, so that the air becomes warmed and humidified.

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