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AVIAN INFLUENZA
Describe the mechanism of
sneeze and cough reflex.
Nahakul Poudel
Roll no :1485
Cough reflex
• Cough is an expulsive reflex that protects the lungs and
respiratory passages from foreign bodies.
• Causes...
Components of cough reflex
• Cough receptors: Rapidly adapting receptors at pharynx,
trachea(carina) ,bronchi and bronchio...
Mechanism of cough reflex
About 2.5L of air is inspired
Epiglottis closes, vocal
cords shut tightly to
entrap the air with...
Mechanism of cough reflex
Abdominal muscles contract
forcefully, pushing against the
diaphragm
Internal intercostal muscle...
Mechanism of cough reflex
Vocal cords and epiglottis
suddenly open widely .
Air is expelled at
velocities ranging from
75 ...
Mechanism of cough reflex
The bronchi and non-cartilaginous
part of the trachea collapse to form
slits through which air i...
Sneeze reflex
• Sneeze is defined as the involuntary expulsion of air
containing irritants from nose.
• Causes of sneeze
1...
Components of sneeze reflex
• Sneeze receptors: Nasal mucosa, Olfactory receptors
• Afferent nerve : Trigeminal nerve and ...
Sneeze reflex arc
Mechanism of sneeze reflex
• Almost same as that of cough reflex
• Deep inspiration
• Soft palate and uvula depress to par...
Differences between coughing and sneezing
Coughing Sneezing
Irritation of trachea, bronchi ,etc. Irritation of nasal mucos...
Correlation
• Avian influenza
• Coughing
• Sneezing
References
• Guyton and Hall-Textbook of Medical Physiology, 12th
edition
• Ganong’s Review of Medical Physiology, 24th ed...
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Mechanism of cough and sneeze reflex

This is all about the mechanism cough and sneeze reflex on human body.

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Mechanism of cough and sneeze reflex

  1. 1. AVIAN INFLUENZA Describe the mechanism of sneeze and cough reflex. Nahakul Poudel Roll no :1485
  2. 2. Cough reflex • Cough is an expulsive reflex that protects the lungs and respiratory passages from foreign bodies. • Causes of Cough 1. Irritants- smokes, fumes, dusts, etc. 2. Diseased conditions like COPD, tumors, etc. 3. Infections(influenza)
  3. 3. Components of cough reflex • Cough receptors: Rapidly adapting receptors at pharynx, trachea(carina) ,bronchi and bronchioles • Afferent nerves : Vagus and glossopharyngeal nerves • Cough centre : Medulla (nucleus tractus solitarius) • Efferent nerves : Vagus,phrenic and spinal motor nerves • Effector muscles : Glottis, external intercostal, diaphragm, major inspiratory and expiratory muscles
  4. 4. Mechanism of cough reflex About 2.5L of air is inspired Epiglottis closes, vocal cords shut tightly to entrap the air within the lung
  5. 5. Mechanism of cough reflex Abdominal muscles contract forcefully, pushing against the diaphragm Internal intercostal muscles also contract forcefully Pressure in the lungs rises to 100mmHg or more. Markedly positive intrathoracic pressure causes narrowing of the trachea.
  6. 6. Mechanism of cough reflex Vocal cords and epiglottis suddenly open widely . Air is expelled at velocities ranging from 75 to 100 miles/hr.
  7. 7. Mechanism of cough reflex The bronchi and non-cartilaginous part of the trachea collapse to form slits through which air is forced,which clears out any irritants attached to the respiratory lining
  8. 8. Sneeze reflex • Sneeze is defined as the involuntary expulsion of air containing irritants from nose. • Causes of sneeze 1. Irritation of nasal mucosa 2. Excess fluid in airway
  9. 9. Components of sneeze reflex • Sneeze receptors: Nasal mucosa, Olfactory receptors • Afferent nerve : Trigeminal nerve and olfactory nerve • Sneeze centre : Medulla • Efferent nerve : trigeminal and vagus nerves • Effector muscles : pharyngeal , tracheal and respiratory muscles
  10. 10. Sneeze reflex arc
  11. 11. Mechanism of sneeze reflex • Almost same as that of cough reflex • Deep inspiration • Soft palate and uvula depress to partially close the mouth • Air is trapped by shutting off its exit passages through the nasopharynx and oral cavity • Opened glottis • Expulsion of irritants from both nose and mouth at high pressure
  12. 12. Differences between coughing and sneezing Coughing Sneezing Irritation of trachea, bronchi ,etc. Irritation of nasal mucosa Vagus and glossopharyngeal nerves Trigeminal nerve Closed glottis Opened glottis Reflex, voluntary Reflex
  13. 13. Correlation • Avian influenza • Coughing • Sneezing
  14. 14. References • Guyton and Hall-Textbook of Medical Physiology, 12th edition • Ganong’s Review of Medical Physiology, 24th edition

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