sense of smell


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sense of smell

  1. 1. THE NOSE
  2. 2. • Olfactory bulb – process all the odor when the olfactory receptor or smell receptor cells which are present further inside the olfactory bulb bring the information. • Nasal cavity-- helps carry the gases to filter the air that enters the lungs, along with the production of micro-organisms. • Nostril– warms air on inhalation and removers moisture on exhalation. • Hard palate -- helps form sounds in speech. Another function of hard palate is to allow food to be chewed while still being able to breathe. • Soft palate -- prevents food from entering the nasal cavity during chewing and swallowing.
  3. 3. The nose is the organ responsible for the sense of smell. The cavity of the nose is lined with mucous membranes that have smell receptors connected to the olfactory nerves. The receptors for smell are found at the olfactory epithelium located at the very top of the nasal passages. They are sensitive to gases and volatile substances that have dissolved in the air
  4. 4. The importance of the nose • The nose not only heats atmospheric air to body temperature by spinning it inside the nasal cavity, but it also moistens the air so that it does not dry out the delicate tissue further down the airway. • The nostrils contain tiny hairs to trap dust, pollen and other airborne particles, and the sticky mucus catches those that the hairs miss. Bacteria are also trapped by mucus and killed by an enzyme found there, or by the concentration of nitric oxide gas that the nose produces.
  5. 5. • The mouth, which is the start of the digestive tract, can also be breathed through, but when this happens the body does not receive the same benefits as when the nose is used. Saliva doesn't do the same job as mucus, and there is no spinning of air, warming, moistening or cleaning anywhere near the same degree as found in the nose. • Compared to the mouth, the nasal passages are small, and so less air is likely to be inhaled through the nose, which is useful if you are moving at a reasonable speed or resting, because at these times the breathing should be of a smallish volume. • Yet, while the volume is less, the efficiency of the nose is better. Due to the intricate construction of the nasal passages, air to be driven deeper into the lungs, and as a result, 10% more oxygen reaches the alveoli for gas exchange and transfer into the bloodstream. • It is harder to exhale forcefully through the nose than it is through the mouth, which means that you are less likely to disturb the finely tuned ratio of gases in the lungs if you use your nose to breathe in and out with.
  6. 6. Common diseases of the nose • Anosmia -- Loss of smell • Deviated Nasal Septum -- The nasal septum is the part of the nose that separates the two airways and the nostrils. A deviated septum is when there is a shift from the midline or center position. The septal deviation may be severe enough to obstruct the passage of air through the nostrils. This obstruction may predispose the patient to sinusitis, infection and epistaxis (nose bleeds). • Epistaxis (nosebleeds) -- The cause may be a trauma to the nose, but many times the nose bleeds because of nasal congestion due to a nasal allergy,sinus infection, or a cold that irritates and weakens the delicate nasal lining.
  7. 7. • Nasal Airway Obstruction-- Blockage/obstruction of the flow of air through the nasal passages most commonly caused by nasal fracture, allergies, deviated nasal septum, nasal deformity and enlarged adenoid tissue. • Nasal Polyps-- A protruding growth from the mucous membrane most commonly caused by chronic infection and allergies. • Rhinitis-- An inflammation of the mucous membrane of the nose. Commonly caused by allergies . Symptoms may include sudden attacks of sneezing, swelling of the nasal mucosa, watery discharge from the nose, itching, watering of the eyes. • Sinusitis-- Sinusitis is an infection of the sinuses near the nose. These infections usually occur after a cold or after an allergic inflammation. There are other possible conditions that can lead to sinusitis. These may include:
  8. 8. These may include: • abnormalities in the structure of the nose • enlarged adenoids • infections from a tooth • trauma to the nose foreign objects that are stuck in the nose Symptoms may include: • runny nose or cold symptoms that last longer than seven to 10 days • complaints of drip in the throat from the nose • headaches • facial discomfort • bad breath • cough • fever
  9. 9. THE END
  10. 10. PREPARED BY: Clarace Ian Haudar Rona Grace Garcimo Ma.Lyn Bravo Ma.Carla Faderon