sympathetic innervation: superior, middle, inferior ganglion Flashcards
what is the sympathetic nervous system a division of?
the autonomic nervous system
mechanism of sympathetic NS?
involuntary
action of SNS?
acts with the parasympathetic system to maintain body homeostasis
‘fight or flight’ response
where do the sympathetic fibres begin?
in the spinal cord
Where do the sympathetic nerve fibres originate from?
from the thoracic region (T1-6)
how do the sympathetic nerve fibres reach structures in the H+N?
ascend from T1-6
After leaving the spinal cord, what do the fibres enter?
the sympathetic chain
where does the sympathetic chain span?
spans from the base of the skull to the coccyx
what is the sympathetic chain formed by?
formed by nerve fibres and ganglia (collections of nerve cell bodies)
how many ganglion are there within the sympathetic chain? what are they?
There are three ganglia within this chain that are of interest – the superior, middle and inferior cervical ganglia
what do the sympathetic fibres synapse with?
with ganglia (nerve cell bodies making up the sympathetic chain)
where do post ganglionic branches continue into?
the head and neck
what are each of the 3 ganglia related to?
specific arteries in the head and neck.
how do the post-ganglionic fibres reach target organs?
The post-ganglionic fibres hitch-hike along arteries (and their branches - related to the ganglia) in order to reach their target organs
what is the cervicothoracic ganglion?
In some individuals, the middle cervical ganglion is often absent and the inferior cervical ganglion is often fused with the first thoracic ganglion
which 2 ganglion are commonly connected together?
the superior and middle cervical ganglia
where is the superior cervical ganglion?
located posteriorly to the carotid artery, and anterior to the C1-4 vertebrae
which important post ganglionic nerves arise from the superior cervical ganglion?
Internal carotid nerve External carotid nerve Nerve to pharyngeal plexus Superior cardiac branch Nerves to cranial nerves II, III IV, VI and IX Gray rami communicantes
where does internal carotid nerve (post-ganglionic nerve from superior cervical ganglion) travel? forming?
hitch-hikes along the internal carotid artery, forming a network of nerves
what do branches from the internal carotid plexus innervate?
structures in the eye, the pterygopalatine artery and the internal carotid artery itself
where does external carotid nerve (post-ganglionic nerve from superior cervical ganglion) travel? forming?
hitch-hikes along the common and external carotid arteries, forming a network of nerves
what does external carotid nerve innervate?
smooth muscle of the arteries
what does Nerve to pharyngeal plexus combine with? forming?
combines with branches from the vagus and glossopharyngeal nerves to form the pharyngeal plexus
what does superior cardiac branch contribute to?
contributes to the cardiac plexus in the thorax
where do Gray rami communicantes distribute sympathetic fibres to?
distributes sympathetic fibres to the anterior rami of C1-C4
where is the middle cervical ganglion located?
anteriorly to the inferior thyroid artery and the C6 vertebra
post-ganglionic fibres of the middle cervical ganglion?
grey rami communicantes
thyroid branches
middle cardiac branch
where do grey rami comminucantes distribute its sympathetic fibres to? (branch of middle cervical ganglion)
to the anterior rami of C5 and C6
where do thyroid branches travel along? (branch of middle cervical ganglion)
travel along the inferior thyroid artery
where does thyroid branches distribute their fibres?
larynx, trachea, pharynx and upper oesophagus
what does middle cardiac branch contribute to? (branch of middle cervical ganglion)
contributes to the cardiac plexus in the thorax
where is the inferior cervical ganglion is situated?
anteriorly to the C7 vertebra
what does inferior cervical ganglion occasionally fuse with? forming?
the first thoracic vertebrae, forming the cervicothoracic ganglion
how many post-ganglionic fibres arise from inferior cervical ganglion? what are they?
3 branches:
Gray rami communicantes
Branches to the subclavian and vertebral arteries
Inferior cardiac nerve
where does gray rami communicantes distribute its sympatehtic fibres to? (branch of inferior cervical ganglion)
to the anterior rami of C7, C8 and T1
what do Branches to the subclavian and vertebral arteries innervate? (branch of inferior cervical ganglion)
the smooth muscle present in the arteries
what does inferior cardiac nerve contribute to? (branch of inferior cervical ganglion)
contributes to the cardiac plexus in the thorax
