Autonomic Pathways Flashcards
Fibres from hypothalamus?
Medial forebrain bundle
Where do preganglionic neurons sit?
Lateral horn
Hippocampus sits where?
Inferior horn of lateral ventricle
Sympathetic innervation?
T1 to l2
Parasympathetic innervation?
Brainstem S2 to S4
Myelination?
Preganglionic- myelinated postganglionic-unmyelinated
Axons from brain stem/ spinal cord do not pass directly to effector organs except?
Sympathetic supply to adrenal medulla
Sympathetic postganglion - neurotransmitter?
Noradrenaline except in sweat glands where it is acetylcholine
Alpha1 antagonist?
Prazosin for hypertension
Beta one antagonist?
Atenolol for hypertension
Beta 2 agonist?
Salbutamol for asthma
Metabotropic receptors?
Alpha 1,2 beta 1,2,3
Sweat glands postganglionic?
Acetylcholine
Postganglionic parasympathetic?
Muscarinic
Muscarinic antagonist?
Atropine, used to treat bradycardia dilated pupils and glandular secretions
How do preganglionic fibres enter sympathetic trunk from lateral horn thoracic?
White rami communicans (myelinated)
Preganglionic fibres either?
synapse in ganglion or
pass through in splanchnic nerves to synapse in prevertebral ganglia
Postganglionic fibres either?
Go To periphery via grey rami communicans back into spinal nerves
or visceral/head via medial branches and plexus
From prevertebral ganglia, postganglionic fibres form plexus around viscera
How many cervical ganglia are there?
Three superior middle and inferior
What is A stellate ganglion
It is a fusion of the inferior Cervical and first thoracic ganglia, which is anterior to the neck of the first rib.
What is stellate ganglion block useful for?
Treatment of chronic pain
How do cervical sympathetic postganglionic fibres travel to the heart?
Via the common carotid artery
Internal carotid plexus supplies and action?
Dilate the pupil and raises the eyelid
Inhibit secretions of the lacrimal gland
External carotid plexus supplies and action?
Inhibits secretions of the submandibular and parotid gland.
Horners syndrome?
Disruption of the sympathetic supply to the head causing constriction of pupil, drooping of eyelid and lack of sweating.
What is miosis?
Constriction of pupil
Ptosis
Dropping of eyelid
Anhidrosis
Lack Of sweating
What are the thoracic splanchnic nerves?
Greater, Lesser least to prevertebral ganglia
Where does oculomotor nerve come from?
Edinger Westphalia nucleus in midbrain
What is the cranial nerve nuclei for the facial nerve?
Superior Salivatory nucleus pons
Which cranial nuclei does the glossopharyngeal nerve come from?
Inferior salivatory nuclei pons
Vagus nerve comes from which nuclei?
Nucleus Ambiguous, dorsal motor nucleus in medulla
Which ganglia are for the cranium?
Ciliary ganglion, Otic ganglion, submandibular ganglion, pterygoPalatine ganglion
Auerbach’s
Regulates muscle contraction
Meissners
Regulates glandula secretions
Afferent pathway?
Dorsal roots, Glossopharyngeal nerve via carotid body/sinus
Vagus nerve via aortic body
In the brainstem descending fibres from hypothalamus innervate?
Parasympathetic cranial nerve nuclei and critical autonomic centres in the ventrolateral medulla
Adrenergic receptors are?
Metabotropic g coupled so slow
A1- blood vessels
B1- Heart
B2- bronchus
In adrenal medulla acetylcholine binds to?
Chromaffin cells which causes release of adrenaline and noradrenaline into circulation
In postganglionic parasympathetic neurons the neurotransmitter is?
Acetylcholine binding to muscarinic receptor g coupled so slow
What is the ratio of pre to postganglionic neurons?
1:20
How do postganglionic sympathetic fibres reach the head?
So from cervical ganglia, they come down through the common carotid then up through the internal/external carotid artery
What causes horners syndrome?
Lesion within brainstem/ cervical spinal cord, anywhere between hypothalamus to preganglionic neurons
Thoracic sympathetic fibres exit via?
Grey rami communicates- spinal nerves
Medial branches- heart and lungs
Sacral splanchnic nerves to pelvic organs are?
Sympathetic whereas others are mainly preganglionic
Sacral parasympathetic level?
S2-S4
What does parasympathetic function do in sexual tissues?
Vasodilation in erectile tissues