Thorax 9 - Vagus Nerves - Autonomics Flashcards
Which structure do the vagus nerves leave the thorax with and therefore at what vertebral level do they pass through the diaphragm?
Oesophagus @ level of T10
Name the 3 autonomic plexuses that the vagus nerve pre-ganglionic branches give rise to.
Pulmonary
Cardiac
Oesophageal
What type of nerve is at risk during thyroid surgery?
Recurrent laryngeal
What can damage to the recurrent laryngeal nerve cause?
Hoarse voice
List some other causes of hoarse voice.
Lung tumour
Enlarged lymph nodes
What does the parasympathetic nervous system supply and not supply?
Head, neck & viscera
Skin & limbs
Where is the parasympathetic ganglion located?
Distant to the cell body, out in the far periphery
Where is the sympathetic ganglion located?
Close to the CNS, short primary neurone, long secondary neurone
Where do the preganglionic sympathetic cell bodies lie in the CNS?
Lateral grey matter of the thoracic spinal cord b/n T1 & L2 - Thoracocolumbar Outflow
Where does the sympathetic trunk lie?
Between the atlas and the coccyx
How does each spinal nerve join onto the postganglionic neurone?
Grey ramus communicantes
What is the spinal level of sympathetic innervation of the upper limb?
T4 to T6
What is the spinal level of sympathetic innervation of the head?
T1 to T3
What is the spinal level of autonomic innervation of the stomach?
T7 to T9
What is the spinal level of autonomic innervation of the oesophagus?
T4 to T6
What is the spinal level of autonomic innervation of the bronchi and bronchioles?
T2 to T4
What is the spinal level of autonomic innervation of the SA node and coronary vessels?
T1
Where do the vagus nerves originate?
Cranial Nerve X & Medulla Oblongata
What type of fibres do the vagus nerves contain and to where do they transmit them?
Sympathetic fibres to the thoracic and abdominal viscera
Describe the course the vagus nerve takes in passing out of the head region.
From medulla oblongata, passes out of the skull with the internal jugular vein. Then passes through the carotid sheath between the internal jugular vein and the common carotid artery.
Where do the vagus nerves lie in relation to the BCV’s and the phrenics?
Posterior to BCV’s
Medial to phrenics
Where does the right vagus nerve lie in relation to the trachea?
Lateral
Where does the right vagus nerve lie in relation to the arch of the azygos vein?
Medial
Where does the right vagus nerve lie in relation to the lung hilum?
Posterior
Which side of the aortic arch does the left vagus nerve pass?
Left
What do the vagus nerves give rise to?
Recurrent laryngeal nerves
What do a. sensory and b. motor branches of the recurrent laryngeal nerves supply?
a. mucosa between vocal folds
b. laryngeal muscles
The right recurrent laryngeal nerve curves superiorly underneath a certain structure. What is this structure?
Right subclavian artery
Describe the course the left recurrent laryngeal nerve follows past the arch of aorta, ligamentum arteriosum, trachea and oesophagus.
Passes under the arch of aorta and posterior to the ligamentum arteriosum, passing superiorly in a groove between the trachea and oesophagus to reach the larynx
Why are the right and left recurrent laryngeal nerves in different places on opposite sides of the body?
Because of the persistence of the ductus arteriosus, the left RL nerve has to hook around the 6th arch, rather than the 4th which the right RL nerve hooks around
