The Autonomic nervous system Flashcards Preview

Neuroanatomy > The Autonomic nervous system > Flashcards

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

Lacrimal glands


Which organs have solely sympathetic innervation

Adrenal medulla, arterioles of skeletal muscle, skin and viscera and kidney.