which nervous system in involuntary? Which is voluntary?
Identify the divisions of the ANS.
- afferent - sensory input
- efferent - motor output
- parasympathetic nervous system - rest and digest
- sympathetic nervous system - fight or flight
Which neurotransmitter stimulates the PNS response? Which neurotransmitter stimulates the SNS response?
What terms are associated with the PNS? What terms are associated with SNS?
What are the receptors in the PNS? What are the receptors in the SNS?
- muscarinic or nicotinic agonists
- alpha 1 or 2, or beta 1, 2, or 3
List tissues involved in 'exceptions' to the general rules of ANS and adrenergic receptors.
- adrenal medulla
- skeletal muscle
- sweat gland
List areas in the ANS where Ach is the neurotransmitter.
- nuerotransmitter at synapse of PNS
- neurotransmitter at effector organ of PNS
- neurotransmitter at synapse of SNS
- neurotransmitter between preganglionic sympathetic nerve and adrenal medullary cells
- neurotransmitter between postganglion and blood vessel walls in skeletal muscle
- neurotransmitter between postganglion sympathetic nerves in sweat glands, innervated by sympathetic cholinergic postganglion fibers
Identify the following tissue responses of the PNS.
- resting heart rate, decrease in contractililty
- increaseing GI activity for digestion and absorption, relax sphincters
- contract sphincter-pupil gets smaller for near vision, constriction of ciliary muscle-reduction of internal pressure in the eye
- glands - generalized secretion
- genitourinary system - detrusor muscle contracts, trigone and sphincter relax
Identify locations of muscarinic and nicotinic receptors.
- effector organ in PNS
- effector organ in sweat glands
- effector organ in skeletal blood vessel
- ganglionic synapse in SNS and PNS
- preganglionic innervation of adrenal medulla
- skeletal muscle of somatic nervous system
How is ach synthesized, where is it stored, and how is it terminated?
- synthesized in the cytoplasm of nerve terminals from acetyl coenzyme and choline
- stored within cholinergic neurons at prejunctional and postjunctional nerve endings
- after ach is released from receptor site it is degraded by acetylcholinesterase, choline is absorbed by nerve to make more ach, acetate enters metabolic pool
- it describes effects of PNS
- salivation, lacrimation, urination, defecation
What is the general rule for effects produced by the receptors in the SNS? Name the prototype adrenergic stimulant.
- fight or flight
Describe the sympathetic response in the following tissue:
cardiovascular, peripheral vascular system, repiratory system, GI system, eye, salivary glands, genitourinary system.
- increase heart rate, increase contractility and conduction velocity
- constricts or dilates coronary blood vessels, constrictions skin and mucosa blood vessels, constricts salivary gland blood vessels
- relaxes bronchioles in lungs
- decreases motility in GI, and constricts sphincters
- contracts radial muscel of iris- pupil dilation (mydriasis), relaxes ciliary muscle, increasing ligament tension on lens and decrease angle of curvature (miosis)
- increases thick saliva flow
- relaxes detrusor muscle walls, constricts trigone and sphincter
How is carbohydrate metabolism effected by EPI?
- direct effect - activity of enzymes in glycogen synthesis and storage are effected, glygcogen is metabolized to utilize glucose in the liver and lactate in skeletal muslce
- indirect effect - new glucose is synthesized because it puts inhibition on insulin secretion, triglyceride breaks down releasing free fatty acids and glycerol in circulation=more energy.
Describe how Nor is synthesized and how it is terminated. compare this mechanism to that of ach. What is the effect on duration of Nor effects?
- synthesized by cells within the reserve pool and stored in the mobile pool. released from intragranular mobile pool, after its released from the receptor it is reuptaken into ANT and stored, it does not have to be resynthesized like ach.
- they have a longer duration
List the therapeutic uses of chlinergic drugs and highlight dental uses.
- applied as eyedrops for a miotic effect
- used to treat xerostomia
- also treat glaucoma
Identify cholinergic drugs used for dental applications.
- pilocarpine (salagen)
- cevimeline (evoxac)
How do anticholinesterase drugs extend cholinergic effects?
they inhibit the enzyme that degrades ach; prolonging the effects of ach
Identify the prototype muscarinic blocking agent drug and the mechanism of action. What is the plant source for this chemical?
- it blocks muscarinic receptors only
- nightshade plant, atropa belladonna
Describe the uses of atropine in dentistry. Memorize the mnemonic.
- used prior to making dental impression material when a dry field is needed.
- toxic doses of atropine=
- dry as a bone (decrease sweating)
- hot as a hare (increased body temperature when body is not cooled by sweating)
- blind as a bat (mydriasis, cycloplegia)
- mad as a hatter (CNS stimulation)
What are the indications for using nicotinic blocking agents in dentistry?
used as skeletal muscle relaxants
describe the uses and action of scopolamine.
- used for surgical premed to gain dual benefit of CNS depression; used as a motion sickness drug; used in treatment of parkinson's disease to reduce tremors
- it is a CNS depressant
What are contraindications for using anticholinergic drugs?
- with glaucoma
- when cardiovascular disease exists
- benign prostate hypertrophy due to urinary retention effect
Identify examples of adrenergic drugs and their therapeutic uses. What doseform is associated with rebound congestion?
- epinepherine, levondefrin - in local anesthetics for local vasoconstriction; also used topically to control minor bleeding
- topical sympathomimetics, drops or sprays to relieve nasal congestion
- drops or spray doseform is associated with rebound congestion
Describe effects of cocaine as a prototype agent.
- it blocks the active uptake of Nor and other catecholamines into the ANT
- it has local anesthetic effect as well as CNS stimulate effects
- vasoconstriction occurs when it is used
- it elevates the mood
describe the effects of amphetamine. When is is used therapeutically?
- increases systolic and diastolic pressure
- increased heart rate and force of contraction
- can also slow heart rate
- difficult urination
- used therapeutically for narcolepsy
- are abused for their CNS affects
Identify two important antiadrenergic drugs. What is a dental consideration when these drugs are taken by a dental pt?
- guanethidine and reserpine
- postural hypotension