Flashcards in The Autonomic nervous system Deck (19):
where are the neurons of the autonomic nervous system?
inside the CNS and the PNS
what are the functions of the ANS?
to maintain homeostasis of the internal environment: gland secretion, heart rate/force of contraction, smooth muscle (organs, blood vessels, piloerector muscles)
what are the characteristics of the visceral efferent pathway?
the preganglionic neuron in the spinal chord exits through the ventral root and the preganglionic axon synapses with and autonomic ganglion which synapses onto a postganglionic axon which then influences the visceral organ.
it can have either an excitatory action or an inhibitory action.
it is autonomous and involuntary
what are the characteristics of the somatic efferent pathways?
the somatic motor neuron exits through the ventral root and immediately reaches the skeletal muscle. Always has an excitatory response
what are preganglionic neurons
neurons inside the CNS. They are finely myelinated axons that exit the CNS
what are post-ganglionic neurons?
neurons in the peripheral ganglia, they are unmyelinated axons that reach the peripheral targets
the efferent ANS is divided into?
sympathetic (ortosympathetic) and parasympathetic (metasympathertic is a subdivision of this)
how is the efferent ANS divided?
position of ganglia, neurotransmitters of visceromotor ganglia, function (mass/restricted, fight/flight or rest/digest)
where are the sympathetic ganglia?
in the paravertebral chain and in the prevertebral/preaortic plexuses
where are the parasympathetic ganglia?
close to the organs they innervate of inside their parenchyma
what is the neurotransmitter released by parasympathetic post-ganglionic fibers?
ACh and they are received by a muscarinic cholinergic receptor
which neurotransmitter is releases by sympathetic post-ganglionic fibers?
release noradrenaline and adrenaline, and the receptor is adrenergic (nicotine based)
Cholinergic drugs mimic which system
The parasympayheic system
What are NANC's
Non-adrenergic non-cholinergic neurons, nitric oxide act as neurotransmitters and neuromodulators. Mostly in the airway system
What is the function of varicosities
They release neurotransmitters into a wide synaptic cleft
Function of the sympathetic pathways
Dilate pupils, lens adjust to far distance, airways open up respiratory rate increases, blood vessels in limbs will dilate, blood to visceral organs will decrease
Function of parasympathetic pathway are
Constrict pupils, lens adjust to close distance, heart rate decreases, lung vessels constrict
Which organs have solely parasympathetic innervation