Nasal cavity surface area

In the absence of reference nasal cavity surface areas and minute ventilations for Cynomolgus monkeys, a default regional gas dose ratio of 1 was assumed (EPA 1994). 

In humans and other mammals, the sense of smell begins when we inhale some odorant through our nose. The inhaled air enters the nasal cavity where it encounters a large number of olfactory neurons located in the nasal epithelium associated with bony structures located at the rear of this cavity. These bony structures are known as turbinates. In a human, these turbinates create a surface area of a few square inches. In a medium-size dog, in contrast, the turbinates have a surface area several times larger. It is small wonder that dogs have a more acute sense of smell than we do. 

The total surface area of the nasal cavity is about 150 cm2, with the area available for absorption enhanced by the convolutions of the turbinates and the presence of microvilli on the surface of the ciliated and unciliated cells of the respiratory epithelium. The arterial supply of the nose is particularly rich in the respiratory epithelium where the Kiesselbach s plexus lies, an area that is rich in numerous capillary loops. The nasal blood flow has been shown to be sensitive to the action of a variety of inhaled compounds, both locally or systemically acting. Clonidine has been shown to decrease the blood flow whereas histamine and phenylephrine have been shown to induce the converse effect. Such direct changes to blood flow are important in determining the rate and extent of drug absorption from the nasal cavity. 

Anatomically, the nasal cavity is divided into two halves by the nasal septum. Each half possesses an approximate total surface area of 75 cm2 and an approximate total volume... 

Nasal cavity. The nasal cavity has a volume of 15 to 20 cm3 and a surface area of 150 to 180 cm2.110 111 The human nasal cavity is divided into two halves by the midline septum.45 107 Each cavity consists of three regions (1) vestibules, which are the anterior sections of the nasal cavity, (2) respiratory region, consisting of turbinates or chonchae (superior, middle, and inferior), and (3) olfactory region, which constitutes about 10 percent of nasal area.45 107... 

The total surface area of both nasal cavities is about 160 cm2. The area available for absorption is enhanced by ... 

The nasal cavity offers a relatively large surface area (approximately 160 cm2) for drug absorption. 

The sophisticated structure and specialized function of airways and membranes in the nasal cavity, and also the small surface area of this region, may limit its capacity for drug delivery. The effect of chronic drug exposure on the integrity of nasal membranes must also... 

The human nasal cavity, bearing a total surface area of about ISOcm and a total volume of about 15mL, is divided by a midline septum into two non-connected parts. As a cross-sectional view is schematically shown in Fig. lA, the nasal cavity consists of several major differentiated regions. " The nasal vestibule is situated just inside of the nostrils, with an area of about 0.6 cm. The epithelial cells in this region are stratified, squamous, and keratinized. The atrium located at the back of the vestibule is the narrowest region, and has stratified squamous cells anteriorly and pseudostrati-fied cells with microvilli posteriorly. The olfactory... 

Turbulence is enhanced by a passage with nonuniform cross section and by twists and turns and protrusions. Notice that the nasal cavity has a large surface area, it is of variable cross section, and the path of the air makes a large turn before entering the throat. The large cross-sectional area means that the air velocity slows from its value at the nostrils, increasing the residence time of the air in the cavity and giving it the time to be heated and humidified. 

The lateral walls of the nasal cavities of mammals are elaborated into folds by the bony turbinates. In the posterior portion of the nasal cavity, much of the surface area of... 

Medical professionals irrigate eyes by introducing flushing fluid at the inner comers of the eyes, thereby sweeping contaminants outward and away from the sensitive lacrimal puncta, or ocular surface drains. Yet traditional eyewash designs actually sweep contaminants toward the inner comers where the lacrimal puncta are located. The eye s lacrimal system is nature s way of maintaming sufficient moisture around the eye. Any excess fluids in this area can be drained down into the nasal cavity via the lacrimal puncta. 

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