Water in the nasal cavity burns because your body is naturally salinity (it has salt). This is why nasal saline doesn't hurt.
The human body is the entire structure of a human organism and comprises a head, neck, torso, two arms and two legs. By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life. These cells are organised biologically to eventually form the whole body.
The nasal cavity (or nasal fossa) is a large air filled space above and behind the nose in the middle of the face. Each cavity is the continuation of one of the two nostrils.
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils. On average the nose of a male is larger than that of a female.
The nose has an area of specialised cells which are responsible for smelling (part of the olfactory system). Another function of the nose is the conditioning of inhaled air, warming it and making it more humid. Hairs inside the nose prevent large particles from entering the lungs. Sneezing is usually caused by foreign particles irritating the nasal mucosa, but can more rarely be caused by sudden exposure to bright light (called the photic sneeze reflex) or touching the external auditory canal. Sneezing is a means of transmitting infections because it creates aerosols in which the droplets can harbour microbes.
Nasal irrigation or nasal lavage or nasal douche is the personal hygiene practice in which the nasal cavity is washed to flush out excess mucus and debris from the nose and sinuses. The practice is generally well-tolerated and reported to be beneficial with only minor side effects. Nasal irrigation in a wider sense can also refer to the use of saline nasal spray or nebulizers to moisten the mucous membranes.
According to its advocates, nasal irrigation promotes good sinus and nasal health. Patients with chronic sinusitis including symptoms of facial pain, headache, halitosis, cough, anterior rhinorrhea (watery discharge) and nasal congestion are reported often to find nasal irrigation to provide relief. In published studies, "daily hypertonic saline nasal irrigation improves sinus-related quality of life, decreases symptoms, and decreases medication use in patients with frequent sinusitis", and irrigation is recommended as an adjunctive treatment for chronic sinonasal symptoms.
In otolaryngology, empty nose syndrome (ENS) describes a nose that has been physiologically crippled by excessive surgical removal of turbinates in the nose (mainly the inferior turbinates) in a surgical procedure known as 'turbinectomy' or 'conchotomy'. It is therefore an iatrogenic condition that can and should be avoided.