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51 Cards in this Set
- Front
- Back
Describe the pathway of pre-ganglionic ANS motor neurons |
Autonomic motor neurons: Pre-ganglionic contain a cell body in the CNS with its axon extending to the autonomic ganglion (neuronal cell bodies in the PNS). All pre-ganglionic axon terminals release excitatory acetylcholine (ACh). - Some synapse with post-ganglionic neurons in the ganglion and - some with adrenal medulla chromaffin cells (instead of autonomic ganglion). |
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Describe the pathway of post-ganglionic ANS motor neurons |
The cell body is within the autonomic ganglion, from which an unmyelinated axon goes towards the effectors (under unconscious control): -smooth muscle -cardiac muscle -gland Most sympathetic neurons secrete noradrenaline. Sympathetic cholinergic neurons release ACh. Chromaffin cells in adrenal medulla secrete noradrenaline and adrenaline. All parasympathetic neurons secrete ACh. These are either excitatory or inhibitory, depending on neuroendocrine state (i.e. fight or flight? Rest or digest?) |
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Why is the sympathetic division called the thoraco-lumbar division? |
The preganglionic neurons have their cell bodies in the lateral horns of the gray matter in the spinal cord T1-L2 (and sometimes L3) |
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Why is the parasympathetic division of the ANS pathway called cranio-sacral? |
The pre-ganglionic motor neuron cell bodies are found in the brain stem or in the gray matter of spinal cord segments S2-S4 |
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Where do the axons of the pre-ganglionic nerve cells (in the thoraco-lumbar divison of the ANS motor pathways) exit? |
Via the anterior root from the spinal cors |
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How are the pre-ganglionic axons of the parasympathetic cranio-sacral division of the ANS motor pathways conveyed? |
1. Brain stem pre-ganglionic axons conveyed via CN III oculomotor, VII facial, IX glossopharyngeal, X vagus 2. S2-S4 pre-ganglionic axons conveyed via anterior roots of pelvic splanchnic nerves |
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Where do the pre-ganglionic axons of the thoraco-lumbar autonomic neurons go to in the motor pathway? |
Sympathetic paravertebral ganglion change (aka sympathetic trunk) via white ramus communicans |
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What are the types of parasympathetic ganglia that axons of the cranio-sacral pre-ganglionic axons extend to? |
1. Intramural ganglia - in wall of innervated organ 2. Terminal ganglia - located near innervated organ (see pic) |
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What are the effectors of the vagus outflow (X) (parasympathetic division)? |
Heart, lungs, stomach, small intestine, part of large intestine, liver, gallbladder, pancreas |
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What are the effectors of the S2-S4 outflow (the parasympathetic pelvic splnachnic nerves)? |
Part of large intestine, reproductive organs, ureters, urinary bladder |
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What are four possible ways that axons can leave the sympathetic trunk? |
Form the: 1. Spinal nerves 2. Splanchnic nerves to adrenal medulla 3. Sympathetic nerves 4. Splanchnic nerves to abdominalpelvic organs |
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Describe the sympathetic pathway for the pre-ganglionic axon involving the spinal nerve? |
After synapsing with post-ganglionic neurons in the sympathetic trunk ganglion, they leave via gray ramus communicans to the spinal nerve. Effectors: skin of the neck, trunk, and limbs via the posterior and anterior rami |
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Describe the sympathetic pathway of the pre-ganglionic axons involving the sympathetic nerve. |
After the pre and post ganglionic synapsis in the sympathetic trunk ganglion, axons leave and form the sympathetic nerves. Some nerves enter ANS plexuses. Post-ganglionic fibers extend to the thoracic cavity. |
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Describe the sympathetic pre-ganglionic pathway involving the cephalic periarterial nerve fibers. |
After synapsis with post-ganglionic neurons in the superior cervical ganglion (in the sympathetic trunk ganglia), cephalic periarterial nerve fibers innervate innervate visceral effectors of the head |
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Describe the sympathetic pre-ganglionic pathway involving the splanchnic nerve that go to the abdominopelvic organs |
The pre-ganglionic axon passes through the sympathetic chain ganglion and forms the splanchnic nerve which synapse with post-ganglionic neurons in the prevertebral ganglia (aka collateral ganglion) and innervate the abdominopelvic viscera |
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Name the five collateral ganglion of the sympathetic thoraco-lumbar pathway. |
1. Celiac 2. Superior mesenteric 3. Inferior mesenteric 4. Aorticorenal 5. Renal |
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Post-ganglion neurons from the celiac ganglion innervate |
Stomach, liver, gallbladder, pancreas, spleen |
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Post-ganglion neurons from the superior mesenteric ganglion innervate |
Small intestine and proximal large intestine |
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Post-ganglion neurons from the inferior mesenteric ganglion innervate |
Urinary bladder, sex organs, distal large intestine |
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Post-ganglion neurons from the aorticorenal ganglion innervate |
Renal arteries and kidneys |
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Post-ganglion neurons from the renal ganglion innervate |
Cortex of kidneys and ureters |
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Effects on (abdominopelvic viscera) of the post-ganglionic fibers from the prevertebral ganglion include |
Vasoconstriction Decreased digestive activity Urogenital functions |
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What happens to pre-ganglionic axons that pass through the sympathetic chain ganglion and collateral ganglion without synapsing? |
They synapse with the adrenal medulla cells via the splanchnic nerve |
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Where and what type of cholinergic neurons release acetylcholine in the ANS? What hydrolyzes ACh? |
Released by 1. Both sympathetic pre-ganglionic neurons and some post-ganglionic neurons 2. All parasympathetic pre-ganglionic neurons and all parasympathetic post-ganglionic neurons
Hydrolyzed -All at the NMJ -acetylcholinesterase (AChE) |
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What releases noradrenaline in the ANS (adrenergic)? |
Released by 1. Most sympathetic post-ganglionic neurons 2. Adrenal medulla (as hormones)
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How is noradrenaline action terminated? |
It is terminated by neuronal re-uptake by: 1. re-release 2. Intracellular hydrolysis by monoamine oxidase (MAO) or by catechol-O-methyl-transferase (COMT) Also ended by glial uptake |
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Where are nicotine cholinergic receptors located? What is the effect of ACh binding? |
Nervous system: Located in motor endplates at the NMJ of sympathetic and parasympathetic post-ganglionic neurons Endocrine system: all chromaffin cells Always excitatory |
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Where are muscarinic cholinergic receptors located? What is the nature of ACh binding? |
Located on: 1. All parasympathetic effectors 2. Few sympathetic effectors (sweat glands) Binding: Excitatory when sodium channels open Inhibitory when chlorine or potassium channels open |
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Where are α-adrenergic receptors located? What is the nature of noradrenaline and adrenaline binding? |
Located in some sympathetic effectors. Two subtypes of receptors: α1-adrenergic receptors are excitatory, ex. located in dermal and GI blood vessels for vasoconstriction α2-adrenergic receptors are inhibitory, ex. located in GI smooth muscle causing vasodilation, leading to decrease of muscle tone and peristalsis |
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What are the receptor subtypes of β-adrenergic receptors and examples of where are they located? |
β1-adrenergic receptor is excitatory, ex. in heart and skeletal muscle β2-adrenergic receptor is inhibitory, ex. in bronchiolar smooth muscle β3-adrenergic receptor is only in brown fat (aka brown adipose tissue), and plays a role in thermogenesis using mitichondrial metabolism uncoupled from ATP synthesis |
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Where are β-adrenergic receptors generally located? |
Some sympathetic effectors |
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What are the relative potencies of noradrenaline and adrenaline to alpha and beta adrenergic receptors? |
Noradrenaline is more potent to alpha adrenergic receptors than beta adrenergic receptors. Adrenaline is equally potent to alpha and beta receptors. |
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What do visceral autonomic reflexes consist of? |
1. Interoceptors=dendritic end of sensory neuron or receptor cell/tissue 2. Sensory neuron 3. CNS interneuron(s) = integrating center 4. 2 motor neurons: pre- and post-ganglionic 5. Visceral effector |
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What are five parasympathetic visceral reflexes? |
Swallowing, coughing Light reflexes: illuminate one eye causes miosis (pupillary contraction) in both eyes Urination Defecation Digestive motor reflexes Decreased heart rate |
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What are three sympathetic visceral reflexes? |
Cardio accelerator reflexes Vasomotor reflexes (blood pressure increases, change in direction of blood flow) Pupillary dilation reflex (dim late induces mydriasis) |
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From what does the hypothalamus receive input? |
Cerebral cortex, limbic system |
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What does output from the parts of hypothalamus influence in the ANS? Together, what do these parts achieve? |
Anterior and medial hypothalamic nuclei influence parasympathetic function. Posterior and lateral hypothalamic nuclei influence sympathetic function. Together: autonomic tone (balance between sympathetic and parasymp) via reciprical control (if one inc. the other dec.) |
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What is "dual innervation"? |
Most organs receive both sympathetic and parasympathetic input. |
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What organs receive only sympathetic innervation? |
Sweat glands, arrector pili muscle, kidney, spleen, blood vessels and adrenal medullae |
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Name the various parasympathetic and sympathetic nerve "plexuses" (tangled networks of axons) in body cavities |
Cardiac plexus - supplies the heart Pulmonary plexus - supplies the bronchial tree Esophageal plexus -supplies the esophagus Celiac plexus - stomach, pancreas, liver, gallbladder, kidneys, adrenal medulla, sex organs Superior mesenteric plexus - small and large intestines Inferior mesenteric plexus - large intestine Hypogastric plexus - supply pelvic viscera Renal plexus - renal arteries within kidneys and ureters |
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Why is the sympathetic decision more widespread and longer lasting than the parasympathetic division? |
Because of the degree of divergence : For every single pre-ganglion, there are 20 or more post ganglion neurons in the sympathetic system. In the parasympathetic system, there are only 5 for one. |
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What is the difference between the preganglionic fibers and postganglionic fibers of the sympathetic vs parasympathetic? |
Symp: preganglionic fibers short and postganglionic fibers long Parasymp: preganglionic fibers long and postganglionic fibers short |
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ANX reflex arcs involve: 1. autonomic ____ sensory neurons associated with____ 2. CNS ___ ____ 3. 2 ___ ___ neurons a. ____ neuron b. ____neuron (stimulating ))))( |
1. unipolar; interoceptors |
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Somatic motor pathways include - single motor neuorn in ____ (___) 1. ___ ___in CNS (spinal cord or brain stem) 2. axon that goes to the ___ ___, 3. ____ (ACh released at NMJ) 4. conscious control |
PNS (LMN) 1. cell body; skeletal muscle; excitatory |
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Post-ganglionic ANS motor neuron Neurotransmitters released by most sympathetic are _____. Sympathetic cholinergic release ____ |
noradrenaline; ACh |
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Post-ganglionic ANS motor neuron Chromaffin cells release ___ and ___ All parasympathetic release ___ |
noradrenaline; adrenalin; ACh |
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The two types of sympathetic ganglia include the ___ ___(or ___) ganglia collateral (or _______) ganglia |
sympathetic trunk (paravertebral) collateral (pre-vertebral) |
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The pre-ganglionic axons that synapse with post-ganglionic neurons in the sympathetic paravertebral ganglion chain either leave via the ___ or ___nerve. |
spinal; sympathetic |
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The pre-sympathetic axons that pass through the sympathetic chain ganglion can either synapse with the ____ _____ (i.e. celiac ganglion, superior mesenteric...) or pass through the ____ ___ and synapse with ___ ____ via the ___ nerve. |
collateral; collateral; adrenal medulla; splanchnic |
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Parasympathetic terminal ganglia include: - ____ganglion of CN ___ - ____ganglion of CN ___ -____ganglion of CN ___ -___ganglion of CN ___ |
- ciliary; III - pterygopalatine; VII - submandibular; VII - otic; VII |
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Hypothalamic outputs for parasympathetic functions include the ___ and ___ hypothalamic ___. For sympathetic functions, outputs include ___ and ___ hypothalamic ___ |
anterior; medial; nuclei posterior; lateral; nuclei |