Vagus Nerve

Question 1

How much of the vagus nerve fibres communicate from the body to the brain

Answer 1

80%

Question 2

How much of the vagus nerve fibres communicate from the brain to the body

Answer 2

20%

Question 3

What does the vagus nerve control

Answer 3

Muscles that you use to swallow and speak And body’s response to rest/relaxation

Question 4

What is the vagus nerves sensory function

Answer 4

Innervates the skin of the external acoustic meatus and internal surfaces of the laryngopharynx and larynx
Provides visceral sensation to the heart and abdominal viscera

Question 5

What is the vagus nerves special sensory function

Answer 5

Provides taste sensation to the epiglottis and root of the tongue

Question 6

What is the vagus nerves motor function

Answer 6

Provides innervation to the majority of the muscles of the pharynx, soft palate and larynx

Question 7

What is the vagus nerves parasympathetic function

Answer 7

Innervates the smooth muscle of the trachea, bronchi and gastrointestinal tract and regulates heart rhythm

Question 8

What are the 4 vagal nuclei

Answer 8

Dorsal motor nucleus
Nucleus ambiguus
Solitary nucleus
Spinal trigeminal nucleus

Question 9

What does the dorsal motor nucleus do

Answer 9

Supply parasympathetic efferent primarily to the gastrointestinal tract and lungs

Question 10

What does the nucleus ambiguus do

Answer 10

Efferent fibres supply muscles of the soft palate, pharynx and larynx
Also gives rise to branchial efferent fibres and preganglionic parasympathetic neurons for the heart

Question 11

What does the solitary nucleus do

Answer 11

Receives primary afferents from visceral organs as well as taste information

Question 12

What does the spinal trigeminal nucleus do

Answer 12

Relay sensory information regarding pain, temperature and deep touch of the outer ear, the dura of the posterior cranial fossa and the mucosa of the larynx

Question 13

What does the Auricular branch of the vagus nerve supply

Answer 13

Sensation to the posterior part of the external auditory canal and external ear

Question 14

What does the vagus nerve pass through in the neck

Answer 14

The carotid sheath

Question 15

How does the vagus nerve travel within the neck

Answer 15

Inferiorly with the internal jugular vein and common carotid artery

Question 16

Where does the right vagus nerve pass

Answer 16

Anterior to the subclavian artery and posterior to the sternoclavicular joint entering the thorax

Question 17

Where does the left vagus nerve pass

Answer 17

Inferiorly between the left common carotid and left subclavian arteries, posterior to the sternoclavicular joint entering the thorax

Question 18

What are the 4 branches which the vagus nerve breaks into in the neck

Answer 18

Pharyngeal branch
Superior laryngeal nerve
Right recurrent laryngeal nerve
Left recurrent laryngeal nerve

Question 19

What does the pharyngeal branch of the vagus nerve do

Answer 19

Provide motor innervation to the majority of the muscles of the pharynx and soft palate

Question 20

What does the external laryngeal nerve of the vagus nerve do

Answer 20

Innervate the cricothyroid muscle of the larynx

Question 21

What does the internal laryngeal nerve of the vagus nerve do

Answer 21

Provide sensory innervation to the laryngopharynx and superior part of the larynx

Question 22

What does the right recurrent laryngeal nerve of the vagus nerve do

Answer 22

Innervates the majority of the intrinsic muscles of the larynx

Question 23

What is the pathway of the left recurrent laryngeal nerve of the vagus nerve

Answer 23

Hooks underneath the aortic arch before transcending towards the larynx

Question 24

In the thorax what does the right vagus nerve form

Answer 24

The posterior vagal trunk

Question 25

In the thorax what does the left vagus nerve form

Answer 25

The anterior vagal trunk

Question 26

What do the vagal trunks of the vagus nerve contribute to

Answer 26

The formation of the oesophageal plexus which innervates the smooth muscle of the oesophagus

Question 27

In the thorax what are the 2 other branches of the vagus nerve

Answer 27

Left recurrent laryngeal nerve Cardiac branches

Question 28

What do the cardiac branches of the vagus nerve do

Answer 28

Innervate/regulate heart rate and provide visceral sensation to the organ

Question 29

How does the vagus nerve enter the abdomen

Answer 29

The vagal trunks enter the abdomen via the oesophageal hiatus - an opening in the diaphragm

Question 30

How does the vagus nerve terminate in the abdomen

Answer 30

By dividing into branches that supply the oesophagus, stomach and the small and large bowel - up to the splenic flexure

Question 31

What are the muscles of the pharynx innervated by

Answer 31

The pharyngeal branches of the vagus nerve

Question 32

What 5 pharynx muscles are innervated by the vagus nerve

Answer 32

Superior, middle and inferior pharyngeal constrictor muscles Palatopharyngeus Salpingopharyngeus

Question 33

What is the stylopharyngeus innervated by

Answer 33

The glossopharyngeal nerve

Question 34

What is the 6th pharynx muscle that is not innervated by the vagus nerve

Answer 34

The Stylopharyngeus muscle

Question 35

What are the 5 recurrent laryngeal muscles

Answer 35

Thyro arytenoid Posterior crico arytenoid Lateral crico arytenoid Transverse and oblique arytenoids Vocalis

Question 36

What is the external laryngeal muscle

Answer 36

Cricothyroid

Question 37

How does the vagus nerve help cardiac function

Answer 37

Cardiac branches arise in the thorax conveying parasympathetic innervation to the sino atrial and atrio ventricular nodes of the heart Stimulates reduction in the resting heart rate

Question 38

What would happen to the heart rate if the vagus nerve was damaged

Answer 38

The resting heart rate would increase

Question 39

How does the vagus nerve help with the gastrointestinal system

Answer 39

Provides parasympathetic innervation to the majority of abdominal organs Sends branches to the oesophagus, stomach and intestinal tract - up to the splenic flexure of the large colon Stimulate muscle contraction and glandular secretions in these organs

Question 40

How does the vagus nerve stimulate muscle contractions in the parasympathetic nervous system

Answer 40

Releases acetylcholine at the synaptic junction with secreting cells, intrinsic nervous fibres and smooth muscles Acetylcholine binds to nicotinic and muscarinic receptors to stimulate muscle contraction

Question 41

How is the vagus nerve related to swallowing

Answer 41

It’s motor fibres innervate all striated muscles of the larynx and pharynx expect the stylopharyngeus and the tensor veli palatini muscles

Question 42

Which cranial nerves does vomiting (emetic) center coordinate reflex through

Answer 42

Trigeminal Facial Glossopharyngeal Vagus Hypoglossal

Question 43

What are the stages of vomiting occurring

Answer 43

Stimulus in medulla oblongata Cranial nerve respond Hypersalivation, pallor, sweat, tachycardia Glottis closes - soft palate rises to close off airway Deep inspiration diaphragm contracts Gastroesophageal sphincter and fundus of stomach relax Abdominal muscles contract forcefully Antiperistaltic waves Increased pressure forces chyme upward from stomach out of mouth

Question 44

What are the 4 stages of coughing

Answer 44

Receptorial phase Inspiratory phase Compressive phase Expiratory phase

Question 45

What is the receptorial phase of coughing

Answer 45

Stimulation to cough receptors send an impulse via the vagus nerve

Question 46

What is the Inspiratory phase of coughing

Answer 46

Wide opening of the glottis by contraction of the arytenoid cartilage with rapid inhalation

Question 47

What is the compressive phase of coughing

Answer 47

Closure of the glottis following contraction of the adductor muscles of the arytenoid cartilages with consequent adduction of the vocal cords Contraction of the abdominal muscles and other expiratory muscles resulting in an increased intrapulmonary pressure and compression of the alveoli and bronchioles

Question 48

What is the expiratory phase of coughing

Answer 48

Vocal cords and epiglottis open causing air from lungs out Exhalation continues until complete relaxation of the diaphragm

Question 49

Which nerve is related to the afferent limb of a gag reflex

Answer 49

Glossopharnygeal nerve

Question 50

What does the afferent limb of the glossopharyngeal nerve do during a gag reflex

Answer 50

Inputs to the nucleus solitarius and the spinal trigeminal nucleus

Question 51

Which nerve is related to the efferent limb of a gag reflex

Answer 51

Vagus nerve from the nucleus ambiguus