Nasal cavity

Short characteristic of a nasal cavity

Nasal cavity – the cavity which is the beginning of a respiratory way of the person. It represents the air channel which is in front reported with external environment (through nose openings), and behind – with a nasopharynx. In a nasal cavity olfactor organs are located, and the main functions consist in warming, clarification from foreign particles and moistening of the arriving air.

Structure of a nasal cavity

Walls of a nasal cavity are formed by skull bones: trellised, frontal, the lacrimal, wedge-shaped, nasal, palatal and maxillary. The nasal cavity from an oral cavity is delimited by a hard and soft palate.

The outside nose is a front part of a nasal cavity, and pair openings behind connect it to a pharyngeal cavity.

The nasal cavity is divided into two half, everyone them whom five walls have: lower, upper, medial, lateral and back. Cavity halves not absolutely symmetric as the partition between them is, as a rule, slightly rejected aside.

The most complex structure at a lateral wall. On it three nasal sinks hang down inside. These sinks serve for department from each other upper, average and lower nasal the course.

In addition to a bone tissue the cartilaginous and webby parts differing in mobility enter a structure of a nasal cavity.

The threshold of a nasal cavity is covered by the flat epithelium which is continuation of an integument from within. In a connective tissue layer under an epithelium roots of setaceous hair and sebaceous glands are put.

Blood supply of a nasal cavity is provided by a front and back trellised and wedge-shaped and palatal artery, and outflow – a wedge-shaped and palatal vein.

Outflow of a lymph from a nasal cavity is carried out in mental and submandibular lymph nodes.

In a structure of a nasal cavity distinguish:

• The upper nasal course which is located only in back department of a nasal cavity. As a rule, it is twice shorter than a half-speed. In it back cells of a sievebone are open;
• The average nasal course located between average and lower sinks. Via the channel in the form of a funnel the average nasal course is reported with front cells of a sievebone and a frontal sinus. This anatomic communication explains transition of inflammatory process to a frontal sinus at cold (frontal sinusitis);
• The lower nasal course passes between a bottom of a nasal cavity and the lower sink. It is reported with an eye-socket through a nasal duct that provides intake of the lacrimal liquid in a nasal cavity. Owing to such structure nasal allocations amplify when crying and, on the contrary, eyes rather often "water" at cold.

Features of a structure of a mucous membrane of a nasal cavity

The mucous membrane of a nasal cavity can be divided into two areas:

• Upper nasal sinks, and also upper part of average nasal sinks and partitions of a nose the olfactory area borrows. This area is covered by the pseudo-multilayer epithelium containing the neurosensory bipolar cells which are responsible for perception of smells;
• Other part of a mucous membrane of a nasal cavity is occupied by respiratory area. It is also covered by a pseudo-multilayer epithelium, but it contains scyphoid cells. These cells emit slime which is necessary for air moistening.

Irrespective of area a plate of a mucous membrane of a nasal cavity rather thin also contains in the structure glands (serous and mucous) and a large amount of elastic fibers.

The nasal cavity submucosa rather thin also contains:

• Adenoid tissue;
• Nervous and vascular textures;
• Glands;
• Mast cells.

The muscular plate of a mucous nasal cavity is developed poorly.

Functions of a nasal cavity

Treat the main functions of a nasal cavity:

• Respiratory. The air inhaled through a nasal cavity makes the arc-shaped way during which it is cleared, warmed and humidified. Warming of the inhaled air is promoted by the numerous blood vessels and thin-walled veins located in a nasal cavity. Besides, the air inhaled through a nose puts pressure upon a mucous membrane of a nasal cavity that leads to excitement of a respiratory reflex and bigger expansion of a thorax, than at a breath through a mouth. Disturbance of nasal breath, as a rule, is reflected in a physical condition of all organism;
• Olfactory. Perception of smells happens thanks to the olfactory epithelium located in epithelial tissue of a nasal cavity;
• Protective. The sneezing arising as irritation of the termination of a trifacial the rough suspended particles which are contained in air provides protection against similar particles. Dacryagogue promotes clarification at inhalation of harmful impurity of air. At the same time the tear flows down not only outside, but also in a nasal cavity via the lacrimonasal channel;
• Resonator. A nasal cavity with an oral cavity, a throat and okolonosovy bosoms serve as the resonator for a voice.