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A nosebleed, also known as epistaxis, is an instance of bleeding from the nose. [1] Blood can flow down into the stomach, and cause nausea and vomiting. [8] In more severe cases, blood may come out of both nostrils. [9] Rarely, bleeding may be so significant that low blood pressure occurs. [1]
This results in greater airflow through one nostril with periodic alternation between the nostrils. It is a physiological congestion of the nasal conchae, also called the nasal turbinates (curled bony projections within the nasal cavities), due to selective activation of one half of the autonomic nervous system by the hypothalamus.
Here the red blood cells absorb oxygen from the air and then carry it back in the form of oxyhaemaglobin, to nourish the cells. The red blood cells also carry carbon dioxide (CO 2) away from the cells in the form of carbaminohemoglobin and release it into the alveoli through the alveolar capillaries. When the diaphragm relaxes, a positive ...
The volume of air that moves in or out (at the nose or mouth) during a single breathing cycle is called the tidal volume. In a resting adult human, it is about 500 ml per breath. At the end of exhalation, the airways contain about 150 ml of alveolar air which is the first air that is breathed back into the alveoli during inhalation.
However, chronic mouth breathing leads to, or is a sign of, illness, and it does not have mucus in the mouth to trap the unwanted substance unlike the nostrils [5] [6] [7] They end in the microscopic dead-end sacs always opened, though the diameters of the various sections can be changed by the sympathetic and parasympathetic nervous systems.
Nasal obstruction characterized by insufficient airflow through the nose can be a subjective sensation or the result of objective pathology. [10] It is difficult to quantify by subjective complaints or clinical examinations alone, hence both clinicians and researchers depend both on concurrent subjective assessment and on objective measurement of the nasal airway.
Many problems can affect the nose, including: Deviated septum - a shifting of the wall that divides the nasal cavity into halves; Nasal polyps - soft growths that develop on the lining of the nose or sinuses; Nosebleeds; Rhinitis - inflammation of the nose and sinuses sometimes caused by allergies. The main symptom is a runny nose.
During a sneeze, the soft palate and palatine uvula depress while the back of the tongue elevates to partially close the passage to the mouth, creating a venturi (similar to a carburetor) due to Bernoulli's principle so that air ejected from the lungs is accelerated through the mouth and thus creating a low pressure point at the back of the ...