5. The Respiratory System Flashcards
Described the nasal cavity and function as part of respiratory system
The only externally visible part of the respiratory system is the nose. The air enters through the nose by passing through the nostrils. the interior of the nose consists of the nasal cavity, that is divided by a midline nasal septum.
There are olfactory receptors that sense the smell and are located in the mucosa in the superior part of the nasal cavity.
The rest of the mucosa lining the nasal cavity, called the respiratory mucosa, rests on a rich network of veins that warms the air. The mucus produced by this mucosa’s glands moistens the air and traps incoming bacteria and other foreign bodies that are chemically destructed by lysozymes enzymes.
In the nasal mucosa there are ciliated cells. They create a current that moves the seet of contaminated mucus posteriorly toward the pharynx, to be swallowed and digest by stomach juices. When the temperature is too cold, cilia become sluggish allowing mucus to accumulate in the nasal cavity from which it is disposed of through the nostrils.
The lateral walls of the nasal cavity called conchae increase the surface area of the mucosa exposed to the air. In addition they direct the flow of air in a steady pattern over a large area of tissue which warms and humidifies the air before it enters the lungs. Cilia extending from the tissue filter impurities out of the air.
Nasal cavity is separated from the oral cavity by a partition called palate. The palate can be divided in hard palate, if supported by bones, or soft palate, if not supported by bones.
The nasal cavity is surrounded by a ring of paranasal sinuses located in the frontal, sphenoidal, ethmoid and maxillary bones.
