Autonomic Nervous System Flashcards
Sympathetic pre-ganglionic axons are […] in length and have […] post-ganglionic axons.
Short
Long
Parasympathetic preganglionic axons are […] in length and have […] post-ganglionic axons
Long
Short
What effect does sympathetic NS exert on pupils?
Dilation
[…] is the neurotransmitter released by preganglionic axons of the sympathetic NS.
[…] is the neurotransmitter released by postganglionic axons of the symathetic NS.
Acetylcholine
Norepinephrine
[…] is the neurotransmitter released by preganglionic axons of the parasympathetic NS.
[…] is the neurotransmitter released by postganglionic axons of the parasympathetic NS.
Acetylcholine
Acetylcholine
Where are the cell bodies for preganglionic neurons of the parasympathetic NS?
Brainstem and sacrum
Where are the cell bodies for preganglionic neurons of the sympathetic NS?
Thoracic and lumbar spine
Where are the ganglia that contain the cell bodies for postganglionic neurons of the parasympathetic NS?
Close to target organs
Where are the ganglia that contain the cell bodies for postganglionic neurons of the sympathetic NS?
Just outside the spinal cord in paravertebral or prevertebral ganglia
- Preganglionic fibers of the sympathetic division have cell bodies in the […] of the spinal cord (region).
- The fibers enter the sympathetic trunk via the white ramus to synapse on […].
- Postganglionic fibers exit via the gray ramus to enter […]
- Lateral horn
- paravertebral ganglia (chain ganglia)
- one of 31 pairs of spinal nerves
So far, we’ve only talked about sympathetic preganglionic neurons as synapsing on paravertebral ganglia (those closest to the spine). What are all the possible outcomes / places where these neurons can travel to synapse with post-ganglionic neurons?
1) synapse on chain (paravertebral) ganglia at the same level at which they exited the spinal cord
2) Ascend or descend the sympathetic trunk to synapse on another paravertebral ganglia
3) pass through the chain without synapsing in order to synase at prevertebral ganglia
What are the prevertebral ganglia we should be familiar with in the visceral motor plexus?
Celiac ganglion
Mesenteric ganglia
Aorticorneal ganglion
The […] nucleus gives rise to the parasympathetic postganglionic neurons of the oculomotor nerve?
Edinger-Westphal
What two cranial nerves have parasympathetic postganglionic cell bodies in the salivatory nuclei of the pons and medulla?
Facial nerve (pons)
Glossopharyngeal (medulla)
What are the 2 nuclei that house the parasympathetic postganglionic cell bodies of the vagus nerve?
Where are these nuclei located?
Dorsal motor nucleus of vagus
Nucleus ambiguus
Middle medulla
For the parasympathetic division of the occulomotor nerve, the preganglionic cell bodies are in the […] and the postganglionic cell bodies are in the […].
Edinger-Westphal Nucleus
Ciliary Ganglion
For the parasympathetic division of the facial nerve, the preganglionic cell bodies are in the […] and the postganglionic cell bodies are in the […].
Salivatory nucleus (pons)
Pterygopalatine ganglion and submandibular ganglion
For the parasympathetic division of the glossopharyngeal nerve, the preganglionic cell bodies are in the […] and the postganglionic cell bodies are in the […].
Salivatory nucleus (medulla)
Otic ganglion
Describe the effect of dual innervation of the bladder by sympathetic and parasympathetic neurons.
Describe the effect of dual innervation of the intestines by sympathetic and parasympathetic neurons.
Parasympathetic - stimulates digestion and intestinal mobility
Sympathetic - inhibits digestion and intestinal mobility
The gastrointestinal system has a unique system of innervation called the enteric nervous system. Describe this innervation.
In the parasympathetic NS, the receptor for Ach on post-ganglionic neurons is […]
Nicotinic receptor
In the parasympathetic NS, the receptor for Ach on target organ is […]
Muscarinic
Sweat glands are innervated by the sympathetic NS. They are an exception to the rule with regards to the neurotransmitters that are released to activate these glands. Describe this exception
Normally, postganglionic neurons would release NE onto target organs. However, sweat glands are cholinergic, so Ach is released instead (muscarinic receptors)
In the sympathetic NS, the receptor for Ach on post-ganglionic neurons is […]
Nicotinic
In the sympathetic NS, the receptor for NE on target organs is […]
Alpha or Beta adrenergic
Renal vascular smooth muscle is innervated by the sympathetic NS. They are an exception to the rule with regards to the neurotransmitters that are released to activate these glands. Describe this exception
Preganglionic neurons are the same (release Ach onto nicotinic). Postganglionic neurons release dopamine instead of NE.
How are adrenal glands an exception to the normal sympathetic and parasympathetic innervation?
They have “preganglionic” cell bodies in the spinal cord like normal autonomic neurons. However, they have no postganglionic neurons. Instead they release epinephrine and norepinephrine directly into the circulation in response to stimulation by their respective “preganglionic” neurons.
Nicotinic receptors are […] (type of receptor) whereas muscarinic receptors are […] (type of receptor).
Ligand - gated ion channels
G-protein coupled receptors (metabotropic)
Alpha and Beta adrenergic receptors are […] (type of receptors).
GPCRs (metabotropic)
There are 4 subtypes of nicotinic receptors. Which are found in cell membranes of postganglionic neurons in autonomic ganglia?
N2 and NN
When epinephrine and norepinephrine bind to alpha 1 adrenergic receptors (smooth muscle) what is the resulting response?
Contraction
When epinephrine and norepinephrine bind to alpha 2 adrenergic receptors (smooth muscle) what is the resulting response?
Contraction
When epinephrine and norepinephrine bind to alpha 2 adrenergic receptors on presynaptic neuron what is the resulting response?
Reuptake of NT and inhibition of further NT release
When epinephrine and norepinephrine bind to beta adrenergic receptors what is the resulting response in the following tissues:
- Cardiac muscle
- Smooth muscle
- Skeletal muscle and liver
- Contraction
- Relaxation
- Glycogenolysis
Consider a postganglionic parasympathetic neuron that synapses with cardiac muscle.
- What NT is released into synapse?
- What receptor is it interacting with?
- What is the response in the tissue?
- Ach
- Muscarinic type 2
- Decreases heart rate and contractility
Consider a postganglionic sympathetic neuron that synapses with cardiac muscle.
- What NT is released into synapse?
- What receptor is it interacting with?
- What is the response in the tissue?
- Norepinephrine
- Beta 1
- Increase heart rate and contractility
What is the baroreceptor reflex?
Where are these baroreceptors located?
What area of brainstem controls this reflex?
Operates to bring blood pressure back to normal after a sudden change in BP in either direction. There are baroreceptors in the carotid sinus and aortic arch that respond to how stretched out he blood vessels are. If BP suddenly increases quickly, they will stretch more and respond to lower it. If BP suddenly decreases quickly, they will sense a decrease in stretch pressure and respond to raise BP. Controlled by Nucleus solitarius (caudal) and CN 9 and 10.
Explain this diagram, starting with the [Increased BP].
BP suddenly increases –> carotid sinus and aortic arch baroreceptors sense this stretch and send sensory info to nucleus solitarius via CN 9 and CN 10 –> Nu. Solitarius responds by increasing firing of parasympathetic vagal nerve innervation to heart and decreasing firing of sympathetic innervation to heart.
What is orthostatic hypotension? What is the BRR role in this condition?
