Visceral Afferent Pathways Flashcards
Fibers from the solitary nucleus project to ___, which sends preganglionic parasympathetic fibers to sphenopalatine ganglion and to submandibular ganglion. What is the response?
Superior salivatory nucleus
Increased lacrimation and salivation
Fibers from the solitary nucleus project to ___, which sends preganglionic parasympathetic fibers to otic ganlgion. Response?
Inferior salivatory nucleus
Increased salivation
Fibers from solitary nucleus project to ___, which sends preganglionic parasympathetic fibers to scattered ganglia located in larynx, pharynx, thorax, and abdomen. Response?
Dorsal motor nucleus of vagus
Increased secretion
Solitary nucleus projects to ___, which innervates muscles of larynx and pharynx. Response?
Nucleus ambiguus
Deglutition
Describe the carotid body reflex
Stimulus: increased CO2 Sinocarotid nerve (vagus) Nucleus tractus solitarius Reticular formation Phrenic nucleus Diaphragm Response: increased ventilation
Describe carotid sinus reflex
Stimulus: increased blood pressure Sinocarotid nerve (vagus nerve) Nucleus tractus solitarius Reticular formation Dorsal motor nucleus Cardiac branches of vagus Response: decreased cardiac contraction
Describe gag reflex
Stimulus: touching pharyngeal mucosa Glossopharyngeal nerve Nucleus tractus soitarius Reticular formation Nucleus ambiguus Pharyngeal branch of vagus Response: gagging
Describe laryngeal expiration reflex with nucleus ambiguus
Stimulus: to laryngeal mucosa
Internal branch of superior laryngeal nerve (vagus)
Nucleus tractus solitarius and adjacent LER pattern generator and associated brainstem and spinal cord nuclei
Reticular formation (LRST) and LVST
Nucleus ambiguus
Recurrent laryngeal nerve
Glottal control
Response: expiratory cough epoch, airway clearing
Describe laryngeal expiration reflex (LER) with medial motor cell column
Stimulus: to laryngeal mucosa
Internal branch of superior laryngeal nerve (vagus)
Nucleus tractus solitarius and adjacent LER pattern generator and associated brainstem and spinal cord nuclei
Reticular formation (LRST) and LVST
Medial motor cell column
Thoracoabdominal nerves
External abdominal oblique m
Closure of abdominal and pelvic sphincters
Response: expiratory “coughs”
Describe bladder reflex
Visceral afferent nucleus at S2-4 (also lateral reticulospinal tract)
Sacral autonomic nucleus at S2-4
Efferent neurons at S2-4 ->increased volume
Response: voiding
Response: increased bladder tone
Stretch receptors in bladder wall (also after increased volume)
Afferent neurons at S2-4
What is an atonic bladder?
Due to lesions of dorsal roots of S2-4 or dorsal funiculi.
Atonic bladder results in flaccid bladder and increased bladder capacity
Voluntary voiding is possible but incomplete
Related to tabes dorsalis
What is reflex bladder?
Transection of spinal cord above S2 interrupts lateral reticulospinal tracts to sacral autonomic nucleus
Patient is unable to voluntarily void bladder (urinary retention)
After spinal shock, bladder reflex may return without voluntary control, and patient will have automatic reflex voiding or reflex bladder
Describe the taste-salivation reflex pathway
Stimulus: food or fluid
Taste buds
Facial nerve or glossopharyngeal nerve
Nucleus tractus solitarius
Inferior salivatory->otic ganglion->GVE to parotid gland
Or superior salivatory->sphenopalatine ganglion->GVE to submandibular and sublingual glands
Response: salivation
Describe ascending gustatory pathway
SVA fibers in VII, IX, and X Solitary tract and nucleus Ipsilateral medial lemniscus Ventral posterior medial nucleus Primary gustatory cortex
Central processes of GVA neurons travel in solitary fasciculus or tracts and terminate where?
In inferior portion of solitary nucleus
