ANS Worksheet Flashcards
What are the 2 main divisions of the ANS?
Sympathetic and Parasympathetic
What is the broad overall function of each division of the ANS?
Parasympathetic is rest and digest; Vegetative processes - digestion, absorption, excretion, etc.
Sympathetic is fight and flight; response to environment.
Where do parasympathetic nerve fibres emerge from in the CNS?
Cranium (CNIII, CNVII, CNIX, CNX) or Sacrum (S234). Craniosacral.
Where do sympathetic nerve fibres emerge from in the CNS?
T1 to L2. Thoracolumbar.
What is meant by a 2 neuron pathway?
The autonomic motor pathway (GVE?) is a 2 neuron pathway from the CNS/spinal cord to its target. An initial neuron in the CNS extends its axon into the periphery to synapse with a second neuron in the periphery whose axon travels the remaining distance to its target, the 2 neurons synapsing in a ganglion along the path. The first neuron is a pre-ganglionic neuron and the second neuron after the synapse is the post-ganglionic neuron.
The main difference between the autonomic and somatic pathways is that the autonomic motor pathway is a two neuron pathway and the somatic is a one neuron pathway. A somatic neuron is a single neuron travelling all the way from the CNS/spinal cord to its destination in the periphery.
What is a ganglion in the ANS?
A junction box where one neuron synapses (transmits a message) with another neuron.
Where are sympathetic ganglia located?
Paravertebral (beside the vertebral column in a Sympathetic chain) or Prevertebral (in front of the vertebral column) on the surface of major blood vessels, also known as Collateral.
Where are parasympathetic ganglia located?
In terminal ganglia (aka, intramural ganglia), on the surface of the target organ e.g. bladder, stomach, lungs.
The exceptions are the four paired parasympathetic ganglia of the head and neck; ciliary ganglion, pterygopalatine ganglion, otic ganglion, and submandibular ganglion.
Where is the sympathetic chain?
Either side of the spine, on the anterior surface of the transverse process of the vertebra, from C1 to the Coccyx, SCSG to the Ganglion Impar, even though the sympathetic neurons only attach to the spinal cord between T1 and L2.
Where are collateral ganglia located?
Groups of ganglia are found in Plexi on the surface of major blood vessels called, and so are also known as Preaortic ganglia.
Cardiac plexus on aortic arch and pulmonary trunk;
Coeliac/Solar plexus on the coeliac trunk of abdominal aorta;
Superior Mesenteric Plexus on the Superior Mesenteric Artery;
Inferior Mesenteric Plexus on the Inferior Mesenteric Artery;
Superior Hypogastric Plexus on bifurcation of the Abdominal Aorta;
Inferior Hypogastric Plexus/Pelvic Plexus on the Internal Iliac Artery.
Where are terminal ganglia located?
On the surface of target organs - bladder; lungs; stomach. Synapse on the organ it is targeting.
Do parasympathetic fibres travel with somatic nerves, or separately?
With somatic nerves but only a few, CNIII, CNVII, CNIX, CNX, S2, S3, and S4.
Do sympathetic fibres travel with somatic nerves, or separately?
There are sympathetic fibres travelling with almost every somatic fibre to every part of the body.
And some sympathetic fibres will travel separately, e.g. thoracic and lumbar splanchnic nerves.
Which peripheral nerves carry parasympathetic fibres?
CNIII, CNVII, CNIX, CNX, S2, S3, and S4
Which peripheral nerves carry sympathetic fibres?
Nearly all of them!
There are sympathetic fibres travelling with almost every somatic fibre to every part of the body.
