The respiratory system - is a system of organs which are involved in air transport of the respiratory tract, in gas exchange between the organism an

Nasal cavity

The respiratory system — is a system of organs which are involved in air transport of the respiratory tract, in gas exchange between the organism and the environment. It consists of breathing, or pneumatic, tract (nasal cavity, pharynx, larynx, trachea, bronchi) and lungs.

The nasal cavity is divided into right and left sides by the bone-cartilage septum. In each of them there are three nasal winding routes: the upper, middle and lower. Nasolacrimal duct opens in the lower. The mucosa of the upper nasal passage contains the receptors of the olfactory analyzer that perceive odors.

The nasal cavity walls are covered with nasal mucosa with flickering epithelium. Epithelium cilia, while moving, hold and discharge outside the dust and microorganisms, thereby performing a protective function. The air that a person inhales gets warmed or cooled in nasal cavity by the blood that flows through the dense grid of blood capillaries of its mucosa.

The mucosa contains glands that secrete mucus, moistening the air and nasal cavity walls, and detaining and depressing vital functions of pathogenic bacteria that enter with the air. Mucus with dust particles, microorganisms removes from the nasal cavity. Taken from http://worldofschool.org

Next to the nasal cavity are placed four pneumatic sinuses. The biggest of them — are the maxillary sinus, located in the upper jaw on the sides of the nasal cavity, and the frontal. Paranasal sinuses are connected by ducts with the nasal cavity. It often happens inflammation of the sinuses, for example the maxillary — sinusitis. It manifested by a continuous runny nose (often with purulent discharges), headache, decrease sense of smell, a slight fever, chills. Among the complications of sinusitis — rheumatism, heart disease, vascular, bronchial asthma and others.

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Questions:
  • Describe the relationship of the structure and functions of the respiratory tract.

  • Explain why the respiratory tract has protective (barrier) function.

  • Describe the relationship of structure and function of the nasal cavity.

  • What nasal diseases do you know? What is the reason of their appearance?