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how is NS divided? + their structures
- Central NS = brain + spinal cord
- Peripheral NS = everything outside of CNS (cranial nerves, spinal nerves, peripheral nerves, neuromuscular junctions)
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Afferent vs Efferent NS?
- afferent (sensory) - bring info into NS from outside
- efferent (motor) - carries info from NS to periphery
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pathway that info travels in afferent NS?
receptors in periphery > brainstem > diencephalon > cortex
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somatic vs autonomic NS?
- somatic - voluntary, largely involves skeletal muscles
- autonomic - involuntary, largely smooth muscles and glands
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what 2 main results does efferent system produce?
- contraction of muscle
- secretion by glands
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NT and receptor for somatic NS?
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pathway for info in somatic NS?
action potential in motoneuron > EPP (end plate potential) in muscle fiber > depolarization of muscle > contraction
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structure of somatic NS? where is cell body of the neuron located?
- single motoneuron + skeletal muscle innervated
- cell body of motoneuron is located in CNS
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3 divisions of the ANS?
- Sympathetic
- Parasympathetic
- Enteric
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structural components of the ANS?
- preganglionic neuron - cell body in CNS
- interneurons - in sympathetic ganglia at the interaction of pre and post-ganglionic neurons, monitor activity so that we dont overspend/stimulate energy
- postganglionic neuron - outside the CNS
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NT for preganglionic neurons in ANS?
ACh (always this)
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which NT do postganglionic neurons release?
ACh or NE (norepi)
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what is aggregation of cell bodies in CNS called?
nucleus
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what is aggregation of cell bodies in PNS called?
ganglion
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2 types of receptors that postganglionic neurons connect to? + examples
- Adreno-receptors: alpha 1/2, beta 1/2
- Cholinergic: muscarinic, nicotinic (only in pre-gang neurons)
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Sympathetic divison aka?
- thoracolumbar system OR
- adrenergic system
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function of sympathetic division?
mobilize the body for activity, "fight or flight"
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what are the 4 ganglions present in the sympathetic division? + what do they innervate?
- superior cervical ganglion - head: eyes, salivary glands
- celiac ganglion - stomach, small intestines
- superior mesenteric ganglion - small & upper large intestines
- inferior mesenteric ganglion - lower large intestines, anus, bladder, genitalia
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location of preganglionic neurons in sympathetic NS?
intermediolateral cell column (T1-L3)
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projection of preganglionic neurons in sympathetic NS?
- travel from ventral roots & white communicating rami > symp. trunk/paravertebral ganglia > via splanchic nerves > prevertebral ganglia
- at both locations they synapse with postganglionic neurons
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location of postganglionic neurons in symp. NS?
paravertebral ganglia (sympathetic trunk) & prevertebral (collateral) ganglia
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projection of postganglionic neurons in symp. NS?
- in PARAvertebral ganglia: travel via gray communicating rami > spinal nerves > innervates blood vessels + arrector pili muscles + sweat glands
- in PREvertebral ganglia: travel to abdominal and pelvic viscera
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where do postgang. neurons end?
at organ structures they are aiming for
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what are interneurons? aka? location? purpose? how do they do it?
- aka small intensely flourescent (SIF) cells
- located in sympathetic ganglia (not parasymp.)
- purpose: monitor info to prevent overspending of energy
- how: use dopamine as inhibitory NT to prevent binding of ACh to receptor
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how does dopamine relate to Parkinsons?
when theres no dopamine in body > cant get tremors to stop or inihibit muscles from shaking bc interneurons cannot carry out their job
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5 neurotransmitters used in NS?
- ACh
- Norepi
- Epi
- Dopamine
- Vasoactive intestinal peptide (VIP) - GI system
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where is NT ACh found?
- all pregang. neurons
- some postgang. neurons - in parasymp NS + or sweat glands in symp. (exception)
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where is NT dopamine found?
NT of SIF/interneuron cells, found in symp. NS
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where is NT norepi found?
- postgang. neurons of symp. NS
- exception - sweat glands + some blood vessels
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where is NT epi found?
produced by adrenal medulla 4epi : 1norepi ratio
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where is NT VIP found?
in GI system
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7 groups of autonomic ganglia?
- paravertebral gang:
- 1. cervical
- 2. thoracic ganglia
- 3. lumbar ganglia
- 4. sacral ganglia
- prevertebral ganglia:
- 5. superior mesenteric ganglia
- 6. inferior mesenteric ganglia
- 7. celiac ganglia
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neuro-effector junction of ANS vs neuromuscular junction of somatic NS?
- NMJ in SNS- single motoneuron innervates muscle, NT is made and stored in nerve terminal of pregang. neuron
- NEJ in ANS
- postgang. neuron has multiple branches where NTs are made/stored/released, multiple branches can innervate multiple receptors on one target tissue (receptors can be located all over the target tissue not just in one main place unlike in SNS where skeletal muscle has a motor end plate where receptors are found)
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what system is adrenal medulla part of?
autonomic > sympathetic NS
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where does adrenal medulla get its innervation from?
T5-T9
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what is the exception of the symp. NS?
adrenal medulla, because it has no postganglionic neuron (similar to somatic NS)
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what does adrenal medulla secrete?
- 80% epi + 20% norepi
- reverse of postgang. of parasympathetic system
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what is pheochromocytoma?
- tumor of adrenal medulla
- symp. NS on steroids basically
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