PATHWAY OF SALIVA SECRETION FROM

SALIVATORY NUCLEUS TO PAROTID GLAND

FELICIA QUARSHIENII DARKO

WELLINGTON

OUTLINE

INTRODUTION

INFERIOR SALIVATORY NUCLEUS

PATHWAY

INTRODUCTION

All the salivary glands are innervated by parasympathetic nerve fibres

Parasympathetic innervation of the parotid gland is from the inferior salivatory nucleus through the auriculotemporal nerve

SALIVATION STIMULUS

Saliva secretion is enhanced by 2 different types of salivary reflexes:

Simple or unconditioned reflexes Aquired or conditioned reflexes

CONDITIONED STIMULUS

It occurs when chemoreceptors and pressure receptors within the oral cavity respond to the presence of food

On activation these receptors initiate impulses in afferent nerve fibers that carry the information to the salivary center located in the medulla of the brain

The salivary center in turn sends impulses via extrinsic autonomic nerves to the salivary glands to promote salivation

UNCONDITIONED STIMULUS

In this case salivation occurs without oral stimulation

Just thinking about, smelling, or hearing the preparation of pleasant food initiate salivation through this reflex

Also called mouth watering

This reflex is a learned response based on previous experience

INFERIOR SALIVATORY NUCLEUS

Found in the brain as cluster of neurons controlling parasympathetic input to the parotid gland

One of the components of glossopharyngeal nerve (cn ix)

INFERIOR SALIVATORY NUCLEUS

Located in the medulla

Within the general visceral efferent cell column

Immediately medial to the nucleus ambiguus

Inferior to the superior salivatory nucleus

INFERIOR SALIVATORY NUCLEUS

PATHWAY

In the medulla, fibres of the isn join with fibres of the gustatory nucleus, nucleus ambiguus and spinal nucleus of cn v

Exit the medulla as the mixed cn ix between the medulllary olive and the inferior cerebellar peduncle

The fibres then pass through the tympanic nerve into the tympanic plexus in the middle ear

Exit the plexus within the lesser petrosal nerve which passes through the petrous part of the temporal bone and comes to lie in the floor of the middle cranial fossa

PATHWAY

Here, it is lateral to the greater petrosal branch of the facial nerve. The preganglionic fibers from the lesser petrosal nerve usually enter the infratemporal fossa through the foramen ovale to synapse with cells in the otic ganglion, which send postganglionic fibers into the auriculotemporal nerve, a branch of the mandibular division of the trigeminal nerve

PATHWAY

It arises by two roots which embrace the middle meningeal artery just below the foramen spinosum and deep to the lateral pterygoid muscle

It crosses lateral to the sphenomandibular ligament immediately below the spine of the sphenoid and lies close to the inner side of the capsule of the mandibular joint

It then winds around the neck of the back of the condyle below the attachment of the joint capsule and passes upwards to enter the small glenoid lobe of the parotid gland

At the parotid gland, it gives off secretomotor fibres to stimulate saliva secretion

PATHWAYINFERIOR SALIVATORY NUCLEUS.

TYMPANIC BRANCH OF CN IX .

TYMPANIC PLEXUS

LESSER PETROSAL NERVE

OTIC GANGLION

AURICULOTEMPORAL NERVE

PAROTID GLAND

PATHWAY

PATHWAY

THANK YOU