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Nerve supply of the lungs

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Abiral Wagle
Abiral Wagle

The document discusses the nerve supply of the lungs. The lungs receive nerve fibers from the pulmonary plexuses, including parasympathetic, sympathetic, and visceral afferent fibers. Parasympathetic fibers originate from the vagus nerves and act as bronchoconstrictors, vasodilators, and secretomotors. Sympathetic fibers originate from the thoracic spinal cord and act as bronchodilators, vasoconstrictors, and inhibit alveolar gland secretion. Visceral afferent fibers transmit reflexive and nociceptive sensory information. Abnormalities in these nerve pathways contribute to the pathophysiology of bronchial asthma.

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RESPIRATORY SYSTEM OBJECTIVE: TO MENTION THE NERVE SUPPLY OF LUNGS ABIRAL WAGLE 1685
Lungs • A pair of respiratory organs • Primary organ of respiration, gas exchange occurs in the alveoli • Location: Thoracic cavity Right and Left lung separated by mediastinum • Texture: Soft and spongy
Nerve supply of the lungs
Nerves of the lungs and visceral pleura Derived from pulmonary plexuses Parasympathetic, Sympathetic, and Visceral afferent fibers The nerve supply to the lungs is down the bronchial tree - majority of the supply is to bronchi and bronchioles - little signal is given to or from alveoli
Right vagus nerve Right pulmonary plexus Left vagus nerve Left pulmonary plexus Sympathetic trunk Paravertebral ganglia of sympathetic trunk
Parasympathetic fibers • Presynaptic fibers from the Vagus nerve (CN X) • synapse with parasympathetic ganglion cells (cell bodies of postsynaptic neurons) in the pulmonary plexuses • Actions - motor to the smooth muscle of the bronchial tree (bronchoconstrictor) - inhibitory to the pulmonary vessels (vasodilator), - secretory to the glands of the bronchial tree (secretomotor)
Sympathetic fibers • Postsynaptic fibers • Their cell bodies (sympathetic ganglion cells) are in the paravertebral sympathetic ganglia (T2-T5) of the sympathetic trunks • Actions - Inhibitory to the bronchial muscle (bronchodilator) - Motor to the pulmonary vessels (vasoconstrictor) - Inhibitory to the alveolar glands of the bronchial tree— type II secretory epithelial cells of the alveoli
Visceral afferent fibers (Sensory impulses) Reflexive Nociceptive (subconscious sensations (pain impulses) associated with reflexes)
Reflexive afferent fibers • Cell bodies in sensory ganglion of the Vagus n. (CN X) • Accompany the parasympathetic fibers • Impulses from: - Tactile sensation for cough reflexes - Stretch reception of bronchial muscles - Hering-Breuer reflexes (stretch reflex of the lungs) - Pressor reception from pulmonary arteries - Chemoreception (blood gas level) from pulmonary veins
Nociceptive afferent fibers • From visceral pleura and bronchi - accompany the sympathetic fibers to sensory ganglion of upper thoracic spinal nerves • From the trachea - accompany the parasympathetic fibers to the sensory ganglion of the vagus nerve (CN X). • Impulses in response to painful/injurious stimuli - Chemical irritants - Ischemia - Excessive stretch
Correlation with Bronchial asthma • Bronchial asthma - Chronic disorder of the airways - Usually an immunologic reaction - Marked by: - episodic bronchoconstriction - inflammation of bronchial walls - increased mucus secretion - Dysfunction of the airway innervation in asthma leads to its pathophysiology
Nerve supply of the lungs
• Abnormalities in cholinergic and sympathetic innervation • β-Adrenergic blockers and cholinergic agonists induce bronchoconstriction • Mechanism: - Activation of sensory nerves leading to reflexes - Stimulation of receptors located on autonomic nerves (crosstalk between these G-protein- coupled receptors and downstream pathways ensures normal airway function)
• Abnormalities in Nonadrenergic Noncholinergic (NANC) neural pathways • Neuromediators like bradykinin, neurokinin, vasoactive intestinal peptide (VIP), & substance P. • Produce features of clinical asthma involving bronchoconstriction, mucus secretion, vascular hyperpermeability , cough, and vasodilation, a process called 'neurogenic inflammation‘ • The NANC system has been proposed for bronchial hyperreactivity
REFERENCES • Keith L. Moore, Arthur F. Dalley II, Anne M.R. Agur : Moore Clinically Oriented Anatomy • BD Chaurasia’s Human Anatomy (Volume 1: Upper Limb and Thorax) • https://www.ncbi.nlm.nih.gov/pubmed/
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Nerve supply of the lungs

  • 1. RESPIRATORY SYSTEM OBJECTIVE: TO MENTION THE NERVE SUPPLY OF LUNGS ABIRAL WAGLE 1685
  • 2. Lungs • A pair of respiratory organs • Primary organ of respiration, gas exchange occurs in the alveoli • Location: Thoracic cavity Right and Left lung separated by mediastinum • Texture: Soft and spongy
  • 4. Nerves of the lungs and visceral pleura Derived from pulmonary plexuses Parasympathetic, Sympathetic, and Visceral afferent fibers The nerve supply to the lungs is down the bronchial tree - majority of the supply is to bronchi and bronchioles - little signal is given to or from alveoli
  • 5. Right vagus nerve Right pulmonary plexus Left vagus nerve Left pulmonary plexus Sympathetic trunk Paravertebral ganglia of sympathetic trunk
  • 6. Parasympathetic fibers • Presynaptic fibers from the Vagus nerve (CN X) • synapse with parasympathetic ganglion cells (cell bodies of postsynaptic neurons) in the pulmonary plexuses • Actions - motor to the smooth muscle of the bronchial tree (bronchoconstrictor) - inhibitory to the pulmonary vessels (vasodilator), - secretory to the glands of the bronchial tree (secretomotor)
  • 7. Sympathetic fibers • Postsynaptic fibers • Their cell bodies (sympathetic ganglion cells) are in the paravertebral sympathetic ganglia (T2-T5) of the sympathetic trunks • Actions - Inhibitory to the bronchial muscle (bronchodilator) - Motor to the pulmonary vessels (vasoconstrictor) - Inhibitory to the alveolar glands of the bronchial tree— type II secretory epithelial cells of the alveoli
  • 8. Visceral afferent fibers (Sensory impulses) Reflexive Nociceptive (subconscious sensations (pain impulses) associated with reflexes)
  • 9. Reflexive afferent fibers • Cell bodies in sensory ganglion of the Vagus n. (CN X) • Accompany the parasympathetic fibers • Impulses from: - Tactile sensation for cough reflexes - Stretch reception of bronchial muscles - Hering-Breuer reflexes (stretch reflex of the lungs) - Pressor reception from pulmonary arteries - Chemoreception (blood gas level) from pulmonary veins
  • 10. Nociceptive afferent fibers • From visceral pleura and bronchi - accompany the sympathetic fibers to sensory ganglion of upper thoracic spinal nerves • From the trachea - accompany the parasympathetic fibers to the sensory ganglion of the vagus nerve (CN X). • Impulses in response to painful/injurious stimuli - Chemical irritants - Ischemia - Excessive stretch
  • 11. Correlation with Bronchial asthma • Bronchial asthma - Chronic disorder of the airways - Usually an immunologic reaction - Marked by: - episodic bronchoconstriction - inflammation of bronchial walls - increased mucus secretion - Dysfunction of the airway innervation in asthma leads to its pathophysiology
  • 13. • Abnormalities in cholinergic and sympathetic innervation • β-Adrenergic blockers and cholinergic agonists induce bronchoconstriction • Mechanism: - Activation of sensory nerves leading to reflexes - Stimulation of receptors located on autonomic nerves (crosstalk between these G-protein- coupled receptors and downstream pathways ensures normal airway function)
  • 14. • Abnormalities in Nonadrenergic Noncholinergic (NANC) neural pathways • Neuromediators like bradykinin, neurokinin, vasoactive intestinal peptide (VIP), & substance P. • Produce features of clinical asthma involving bronchoconstriction, mucus secretion, vascular hyperpermeability , cough, and vasodilation, a process called 'neurogenic inflammation‘ • The NANC system has been proposed for bronchial hyperreactivity
  • 15. REFERENCES • Keith L. Moore, Arthur F. Dalley II, Anne M.R. Agur : Moore Clinically Oriented Anatomy • BD Chaurasia’s Human Anatomy (Volume 1: Upper Limb and Thorax) • https://www.ncbi.nlm.nih.gov/pubmed/

Editor's Notes

  1. pulmonary plexuses anterior and (mainly) posterior to the roots of the lungs
  2. ( either refl exive (conducting subconscious sensations associated with reflexes that control function) or nociceptive (conducting pain impulses generated in response to painful or injurious stimuli, such as chemical irritants, ischemia, or excessive stretch).)
  3. Both the adrenergic and muscarinic receptors are G-protein-coupled receptors