ANS Flashcards
What are catacholamines
Class of agents secreted in response to stress that include epinephrine nor epinephrine and dopamine involved in neurotransmission
What is the sequence of events for elevated blood pressure through the ANS system
- Visceral sensory output is elevated BP causing excessive stretching to baroreceptors. 2. The stretch receptor signal is transmitted via the sensory division to the CNS where information is processed. 3. A response is effected through motor division of the peripheral NS Ari the ANS and then to the arteries veins and heart to regulate BP
What pathway does ANS follow for organ innervation
The ANS nerve fibers leave the spinal cord to meet a ganglion where they will synapse with a second nerve fiber
SNS pre ganglion’s fibers are relatively _____ as most ganglia are in the paravertebral region and the post ganglion fibers are _____ by comparison
Short and long
Which organs are innervated by both SNS and PNS
Urinary bladder and heart
In the SNS system which part of the fiber actually innervates the target organ or tissue
The postganglionic fibers
What are the different terms for the SNS and the PNS?
SNS is fight flight or fright or the adrenaline rush response and PNS is rest and digest or repair and renew
What is a adrenergic nerve ending?
A nerve ending that releases nor epinephrine as the primary neurotransmitter, this term is also used for a synapse in which norepinephrine is the primary transmitter
What is an adrenergic receptor?
A receptor that binds and is activated by one of the adrenergic transmitters nor epinephrine, epinephrine or dopamine also called an adrenoreceptor
What are autonomic effector cells/tissues
Cells or tissues that have adrenoreceptors or cholioceptors like smooth muscle, cardiac muscle and glands
What is the baroreceptor reflex?
The homeostatic mechanism that maintains a constant arterial blood pressure there are also low pressure venous pressure receptors
What is a cholinergic receptor?
A receptor that binds and is activated by acetylcholine
What is a cholinergic ending?
A nerve ending that releases acetylcholine this term also used for a synapse in which acetylcholine is primary transmitter
What is a dopaminergic nerve ending?
A nerve ending that releases dopamine as the primary neurotransmitter
What are ganglion?
The location where terminals from the first neuron make contact with cell bodies and extensions of the second neuron. these synapses are located in the ganglia
What is the parasympathetic nervous system?
The part of the ANS that originates in the cranial nerves and sacral part of the spinal cord
What is post synaptic receptor?
A receptor located on the distal side of a synapse on the postganglionic neuron or an autonomic effector cell
What is a pre-synaptic receptor
A receptor located on the nerve ending from which the neurotransmitter is released into the synapse this receptor modulates the release of the neurotransmitter
What is the sympathetic nervous system
The part of the ANS that originates in the thoracic and lumbar parts of the spinal cord
What are the primary neurotransmitters in the ANS
Nor epinephrine and acetylcholine
Which neurotransmitter hits preganglionic fibers and postganglionic fibers from the parasympathetic nervous system
Acetylcholine
Which neurotransmitter hits most postganglionic fibers from the SNS
Nor epinephrine
What is the other name for preganglionic fibers?
Efferent fibers
On occasion, which neurotransmitter may be in the SNS but primarily active in the CNS
Dopamine
How is acetylcholine synthesized?
In the cytoplasm from acetyl – COA and choline
Release of acetylcholine is dependent on what?
Extra cellular calcium
When acetylcholine reaches the terminal, what does it trigger?
Sufficient influx of calcium ions
What happens after acetylcholine is released from the pre-synaptic terminal
Acetylcholine molecules bind and activate an acetylcholine receptor. Eventually, all of the acetylcholine released will diffuse within range of an acetylcholinesterase molecule. The acetylcholine esterase molecule very efficiently, splits acetylcholine into Choline and acetate, neither of which has significant transmitter effects and thereby terminates the action of the transmitter.
Why is the half-life of acetylcholine in the synapse very short?
The AChE molecules split acetylcholine and terminates the action
In the adrenal medulla in certain areas of the brain, what is nor epinephrine converted to
Epinephrine
What neurotransmitter terminates synthesis in the CNS
Dopamine
Which two types of receptors are in the postsynaptic neuron
Alpha and beta adrenoreceptors
Where is nor epinephrine stored?
Vesicles in the pre-synaptic neuron
What happened in nor epinephrine termination?
Diffuses away from the receptor and re-uptakes into the pre-synaptic neuron
What kind of drugs block action potential propagation?
Non-selective drugs, such as local anesthetics
What kind of drugs block, neurotransmitter synthesis, and storage?
Highly selective drugs
What kind of drug is sympathomimetic
Adrenergic agonist
What kind of drug is sympatholytic?
Adrenergic antagonist
What kind of drug is para sympathomimetic
Cholinomimetic or cholinergic agonist
What kind of drug is parasympatholytic
Cholinergic antagonist
What catecholamine is released during stress by the adrenal medulla
Epinephrine
What do sympathomimetic drugs mimic?
Epinephrine and nor epinephrine
What do sympatholytic drugs block?
Nor epinephrine and epinephrine
What kind of drugs mimic acetylcholine?
Parasympathomimetic
What do parasympatholytic drugs block or antagonize?
Acetylcholine
What are two examples of alpha one agonist
Phenylaphrine and midodrine
What are two examples of alpha two agonists
Clonidine and methyldopa
What are two examples of alpha one antagonists
Prazosin and labetalol
What is one example of alpha two antagonists
Yohimbine
What are four examples of beta agonists that work on beta one and or two?
Nor epinephrine, dobutamine, epinephrine, and isoproterenol
What are two examples of beta two agonist
Albuterol and terbutaline
what is a example of a nonselective beta one and two antagonist
Propranolol
What is an example of a selective beta one antagonist?
Atenolol and metoprolol
What are three dopamine agonist?
Bromocriptine, pramipexole, and ropinirole
What are three dopamine antagonists?
Zyprexa risperidone and Thorazine
What are the types of adrenergic adrenoreceptors
Alpha one and two agonist alpha one and two antagonist, beta one and two agonist beta, one and two antagonist and dopamine, agonist and antagonist.
What are the types of cholinoreceptors
Acetylcholine receptors and cholinesterase esterase receptors
What are the acetylcholine receptors?
Muscarinic, agonists, muscarinic, antagonist and nicotinic, agonist and nicotinic and antagonist
What are two examples of muscarinic agonist?
Bethanechol and pilocarpine
What are two examples of muscarinic antagonist?
Atropine and hyoscyamine
What is an example of a nicotinic agonist?
Nicotine
What is an example of a nicotine antagonist?
Ganglionic blockers used in anesthesia
What are four examples of cholinesterase and inhibitors
Neostigmine, donepezil, rivastigmine, and Organophosphates like insecticides and nerve gases
Which cholinesterase inhibitors are used in the treatment of Alzheimer’s disease
Donepezil and rivastigmine
Which cholinesterase inhibitor is used to treat myasthenia gravis
Neostigmine
What are potent cholinesterase inhibitors that enhanced transmission at all colonic sites, both nicotinic and muscarinic
The oregano-phosphates parathion and malathion which makes them effective poisons
What cholinesterase inhibitor has been used as a chemical weapon for over 50 years
Sarin but it is only effective when it is composed of two components
Which drug causes vasodilation that can be blocked by atropine
Bethanechol
What does the autonomic nervous system regulate?
Contraction and relaxation of smooth muscles, secretion of exocrine and certain endocrine glands, cardiac rate and contractility and certain steps of intermediary metabolism.
Beta 2selective Agonists are often effective in what?
Asthma
