Autonomic Nervous System Flashcards
2 main divisions of nervous system
CNS & PNS
CNS =
brain and spinal cord
PNS =
motor neurons and sensory neurons, including cranial nerves and spinal nerves
motor neurons
carry motor info from CNS to muscles and glands (efferent)
sensory neurons
carry sensory info from sensory organs to CNS (afferent)
motor neurons can be split into 2
- somatic NS
- autonomic NS
somatic NS
controls voluntary movement
autonomic NS
controls involuntary movement
autonomic NS divisions
- sympathetic division
- parasympathetic division
sympathetic division
fight or flight
parasympathetic division
rest and digest
autonomic pathways are efferent and consist of
2 neurons which synapse in a ganglion
difference in autonomic and somatic
autonomic = 2 neurons which synapse in a ganglion
somatic = direct connection in form of a single neuron
difference in pre and post ganglionic neurons
preganglionic = myelinated
postganglionic = non myelinated
how do preganglionic neurons differ in ANS
sympathetic = shorter preganglionic neurons
parasympathetic = longer preganglionic neurons
what is a ganglion
collection of nerve cell bodies within PNS and the equivalent structure is a nucleus in the CNS
2 neurotransmitters used for communication in ANS are
- acetylcholine
- noradrenaline
effect of the neurotransmitters
excitatory postsynaptic effect
neurons that release ACh are known as
cholinergic fibres
neurons that release NA are known as
adrenergic fibres
what happens at cervical ganglia
the preganglionic sympathetic neurons synapse here before hitch-hiking with arteries to reach their target
where are the cervical ganglia located (3)
superior cervical ganglion - C1/2
middle cervical ganglion C6
inferior cervical ganglion C7
post ganglionic axons from superior cervical ganglion reach their target by
forming a plexus around the common carotid artery and its branches
superior cervical ganglion supplies branches via
ICA & ECA forming plexuses
cervical spinal nerves C1-C4 cervical plexus
pharynx
superior cardiac nerves
middle cervical ganglion supplies branches via
cervical spinal nerves C5-C6
middle cardiac nerves
inferior cervical ganglion supplies branches via
vertebral artery (forming a plexus)
cervical spinal nerves C7-T1 with C7+8 forming brachial plexus
inferior cardiac nerves
cervical ganglia regulate what
sympathetic innervation of eyes, eyelids, lacrimal glands, carotid body, salivary and sweat glands
what causes Horner’s syndrome
damage to the cervical sympathetic trunk in the neck
3 signs and symptoms of Horner’s
- constriction of the pupil (miosis)
- drooping of superior eyelid (ptosis)
- vasodilation and absence of sweating on face and neck
parasympathetic path of CN III (oculomotor)
preganglionic - from Edinger-Westphal nucleus in brain to ciliary ganglion
postganglionic - travel to innervate ciliary muscle and sphincter pupillae
parasympathetic path of CN VII (facial)
superior salvatory nucleus in brainstem to pterygopalatine & submandibular ganglia
pterygopalatine ganglion to lacrimal gland and nasal mucose
submandibular ganglion to submandibular gland via chorda tympani
parasympathetic path of CNIX (glossopharyngeal)
inferior salvatory nucleus to otic ganglion
otic ganglion to parotid gland via auriculotemporal nerve
where is the otic ganglion found
below foramen ovale in infratemporal fossa on the medial side of the mandibular nerve
