Term
| What are the two main nervous systems in mammals? |
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Definition
Autonomic (automatic) and Somatic (conscious control) |
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Term
| The Autonomic Nervous system is divided into what two areas? |
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Definition
| Sympathetic and Parasypathetic |
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Term
| Describe the pre/post nerve structures for the sypathetic and parasympathetic. |
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Definition
Sympathetic has a short preganglionic nerve fiber, and a long post. Parasympathetic has a long preganglionic nerve fiber, and a short post. |
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Term
| Where are the sympathetic and parasympathetic nervous systems based out of? |
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Definition
Sympathetic in the thoraco-lumbar region of the spinal cord. Parasympathetic originates in the brainstem, and in the coccyx of the spinal column. |
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Term
| Why is it that someone can break their neck, be paralzed, but still be alive. |
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Definition
| Breaking the neck severs the sympathetic and somatic nervous systems. But leaves the parasympathetic system in tact (it's in the brainstem as opposed to the spinal cord). Means stress response and conscious movement is out, but normal "rest/digest" functions normally. |
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Term
| The three types of receptors on the plasma membrane of a postganglionic nerve or the organ are: |
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Definition
| Nicotinic, Muscarinic, Adrenergic |
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Term
| Where is acetylcholine found (in terms of nervous systems) |
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Definition
| Both the parasympathetic and sympathetic ganglion. Also found at the adrenal gland, and is used in the somatic nervous system. Only place it's not used is part of the circulating adrenergic system, and at the sympathetic end organs. |
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Term
| How is acetylcholine made? How is it broken down? |
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Definition
Synthesized from choline from diet, and from acetyl coenzyme A (energy derivative) by an enyme, choline acetyltransferase. Acetylcholinesterase is an enzyme that breaks down acetylcholine. |
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Term
| Why won't a pharmacologist give Acetylcholine to a patient? |
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Definition
| It wouldn't work. In the synapse between the pre/post nerves or the post nerve and the organ is acetylcholinesterase which degrades acetylcholine. Meanwhile pseudocholinesterase breaks down any acetylcholine injected into the body. Found in plasma and liver. |
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Term
| If neurotransmitters are fairly ubiquitous (e.g. acetylcholine) how cna drugs have effects in some areas, and none, or opposite in others? |
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Definition
| Differing receptors cause different or nonexistant effects. |
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Term
| How can acetylcholine slow down heart rate but increase digestion? |
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Definition
| Differing types of Muscarinic Receptors. Modds are found in the gut to stimulate muscle contraction, while Meves are found in the heart. |
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Term
| Why don't pharmacologists target the ganglion? |
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Definition
| Doing so would affect both the parasympathetic nervous system, and the nicotinic receptors which would tend to cancel each other. |
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Term
| Describe the catecholamine pathway. |
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Definition
| Amino acid Tyrosine is gathered from diet (mainly meat). Hydroxylated by enzyme tyrosine hydroxylase and adds an OH creating L-Dopa. L-Dopa is hydroxylated again forming dopamine, a neurotransmitter. In the CNS, this is the end of the process. In the sympathetic nervous system, dopamine is hydroxilated by and enzyme, dopamine beta hydroxylase, to make norepinephrine. The adrenal gland transfroms norepinephrine into epinephrine. |
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Term
| How is adrenergic transmission terminated? |
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Definition
Reuptake of norepinephrine and epinephrine into the nerve terminal accounts for 60%. Diffusion of NE and EPI away from synaptic cleft accounts for 20% . Metabolism of NE and EPI into inactive compounds accounts for 20%. |
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Term
| How are drugs like cocain related to adrenergic stimulation? |
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Definition
| They inhibit the reuptake of NE and EPI causing longer/concentrated stimulation of those receptors. |
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Term
| How does cAMP function in smooth muscle? What about in cardiac muscle? |
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Definition
increasing cAMP causes phosphorylation of myosin light chain kinase, which inhibits it's normal function (muscle contraction). Thus it results in decreased muscle contraction. In cardiac muscle increasing cAMP results in faster heart rate and contractility. |
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Term
| What are the two main neurotransmitters for the autonomic nervous system? |
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Definition
| Acetylcholine and Norepinephrine. |
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Term
| Are nicotinic receptors good targets? Muscarinic? Adrenergic? |
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Definition
Nicotinic are poor targets because anything that affects nicotinic receptors can hit both nerves (ganglion) and muscles, so lots of side affects. Also hits both sympathetic and parasympathetic at the same time - no point. Muscarinic are also poor targets usually due to lack of drugs that can specify between the different types. Adrenergic receptors are strong targets with a large selection of drugs that are effective at targeting. |
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Term
| What nerve controls the heart's response? |
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Definition
| The tenth cranial nerve (vagus nerve) |
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Term
| What are the major neurotransmitters at the end organs in the autonomic nervous system? At the ganglions? |
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Definition
Acetylcholine and Norepinephrine at the organs Acetylcholine at the ganglion |
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Term
| Where is acetylcholine found? |
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Definition
Autonomic end organs and ganglion Parasympathetic end organs Somatic neuromuscular junctions |
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Term
| Describe parasympathetic and sympathetic stimulation of the heart. Which is dominant? What are the receptors? |
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Definition
Parasympathetic (M2 receptors): medulla => dorsal motor nerve / nerve ambigous => conduction tissue (near SA or AV) => decreases heart rate / contractility Sympathetic (beta 1 receptors):intermediolateral cell column (in spine) => paravertebral chain => synapse in stellate or middle cervical ganglion => increase heart rate and contractility Parasympathetic is dominant. |
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Term
| Describe parasympathetic and sympathetic innervation of the vasculature. Which is dominant? What are the receptors? |
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Definition
Parasympathetic (alpha1 / non-innervated M3 receptors): minimal innervation. Small amount on venous side of: head, viscera, genitalia, bladder and bowel. Non-innervated M3 receptors on vascular endothelium cause vasodilation via nitric oxide. Sympathetic (alpha1 / beta2): beta2 receptors not connected to nerves. React to circulating epinephrine, overriding alpha1 receptors causing relaxation. Sympathetic dominant. |
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Term
| Describe parasympathetic and sympathetic innervation on the lungs. Which is dominant? What are the receptors? |
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Definition
Parasympathetic (M3): vagus nerve => ganglia in airway wall => blood vessels and glands => bronchoconstriction Sympathetic (beta2, NANC): sparse innervation. promotes bronchodilation from circulating epinephrine. NANC (Non-adrenergic, Non-cholinergic) receptors are a direct pathway to airway smooth muscle that reacts to neuropeptides. Some bronchodilate, some bronchoconstrict |
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Term
| Describe parasympathetic and sympathetic innervation on the GI tract. Which is dominant? What are the receptors? |
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Definition
Parasympathetic (M1,2,3): increase/decrease secretions and smooth muscle contractions. Sympathetic (beta2, alpha1,2): beta2 causes relaxation and less motility. alpha1 promotes contraction closing sphincters, alpha2 inhibits ACh (shuts down parasympathetic) Also has intrinsic nervous system to coordinate complex movement. Parasympathetic is dominant |
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