Autonomic Nervous System Flashcards
From what area in the CNS do sympathetic nerves originate?
thoraco-lumbar
From what area in the CNS do parasympathetic nerves originate?
cranio-sacral
From which part of the spine do no autonomic pathways originate from?
the cervical and lumbar enlargements
What are the two categories of sympathetic ganglia and what do they innervate?
Paravertebral ganlia innervate vasculature and prevertebral ganglia innervate non vascular smooth muscle
Are autonomic nerve fibres myelinated?
preganglionic fibres are either lightly myelinated or unmyelinated but all postganglionic fibres are unmyelinated
Which sympathetic nerve fibres do not use NA as their postganglionic neurotransmitter and what do they use instead?
axons that innervate sweat glands use ACh
What are the differences between an autonomic nerve fibre and a somatic motor nerve fibre?
Autonomic nerves have pre and postganglionic fibres, there is no easily visible junction and they have more than one transmitter release site per axon
Where in the spinal cord are preganglionic autonomic neurons?
in the intermediolateral cell column
What is the function of ganglia in the autonomic nervous system?
ganglia are essential for integration and coordination - they integrate because they have lots of dendrites so can take in a lot of information and integrate it and they coordinate because lots of postganglionic neurons can be innervated by the one preganglionic neuron so you can achieve the same response in many organs
What is the sympathoadrenal system?
adrenal medulla cells are innervated by sympathetic neurons and cause a release of hormones which can circulate to get broad activation of receptors
Which brainstem nuclei contain preganglionic neurons for the parasympathetic nervous system?
edinger westphal nucleus, salivatory nuclei, dorsal motor nucleus of vagus and nucleus ambiguous
What is the pelvic plexus?
a nerve plexus in the pelvis that contains both parasympathetic and sympathetic fibres - means that parasympathetic postganglionic neurons in the pelvis have unusually long axons
What is the major integrative centre for autonomic function and reflexes?
the nucleus of the solitary tract in the medulla
Where do neurons from the nucleus of the solitary tract project to?
either feedback to local spinal reflexes or project to higher centres for more complex behaviours
Which area in the brain is important for coordination of autonomic output?
the hypothalamus
