Chapter 4: Nervous System Flashcards
(25 cards)
Central Nervous System (CNS)
Brain and spinal cord
control center of the entire nervous system
Peripheral Nervous System (PNS)
Somatic nervous system
Autonomic nervous system
Somatic Nervous System
Under conscious control (voluntary)
Autonomic Nervous System
Unconscious control (involuntary)
Normally, target sites have both sympathetic and parasympathetic innervation
Neurotransmitter
A chemical “bridge” between synapses (gaps) between nerves, allowing the “message” to be passed to one or thousands of other neurons. They can be mimicked or blocked by certain drugs
Sympathetic (Adrenergic) Nervous System
Stimulation causes an increase in heart rate and respiratory rate, dilated pupils. Fight or Flight
Parasympathetic (Cholinergic) Nervous System
Stimulation causes a decrease in heart rate and respiratory rate, increases GI activity. Rest and Digest
Primary neurotransmitters for adrenergic sites are
Norepinephrine
Epinephrine
Dopamine
How drugs affect: Autonomic Nervous System
Mimicking neurotransmitters (direct-acting)
Interfering/Changing the neurotransmitter release (indirect-acting)
Blocking the attachment of neurotransmitters to receptors
Interfering/Changing the breakdown or reuptake of neurotransmitters at the synapse
Cholinergic Agents
Drugs that stimulate receptor sites mediated by acetylcholine (neurotransmitter for cholinergic sites)
Parasympathomimetic: effects resemble those produced by the parasympathetic nervous system (rest and digest)
Cholinergic Agents
Reduce intraocular pressure (IOP) - glaucoma
Stimulate GI motility
Control emesis
Treat urinary retention
Act as an antidote for neuromuscular blockers
Aid in diagnosis of myasthenia gravis
Common Direct-Acting Cholinergic Agents
Pilocarpine: reduces IOP in glaucoma, treats KCS (dry eye)
Metoclopramide: promotes gastric emptying, used with GI stasis
Bethanechol: treat lack of GI and urinary muscle tone/contractility
Common Indirect-Acting Cholinergic Agents
Pyridostigmine (Mestinon): treats myasthenia gravis
Neostigmine: used as an antidote to neuromuscular blocking agents, used to treat urinary retention and GI atony (lack of contractility)
Anti-Cholinergic Agents
Drugs that block the action of acetylcholine
Parasympatholytic: reduces the activity of the parasympathetic nervous system
Anti-Cholinergic Agents
Decreases GI motility (helpful with V/D)
Drying of secretions
Prevention of bradycardia
Dilation of pupils
Relief of ciliary spasm of the eye (Atropine drops reduce pain)
Common Anticholinergic Agents
Atropine
Glycopyrrolate
Adrenergic Agents
Sympathomimetic: mimic effects of sympathetic nervous system
Catecholamine: hormones that function as neurotransmitters
Adrenergic Agents
Stimulate heart to beat during cardiopulmonary arrest
Reverse hypotension and bronchoconstriction in anaphylactic shock
Strengthens the heart during congestive heart failure
Vasoconstriction
Treats urinary incontinence
Reduces mucous membrane congestion
Common Adrenergic Agents
Epinephrine: increases heart rate and cardiac output
Norepinephrine: vasopressor (raises blood pressure)
Dopamine: increases blood pressure and cardiac output
Albuterol: bronchodilation
Adrenergic Blocking Agents
Sympatholytic: inhibit activity of the sympathetic nervous system
Alpha Blockers
limited use in vet med
Prazosin: treats urethral spasms secondary to urethral obstructions
Atipamezole: reversal agent for dexmedetomidine
Acepromazine: tranquilizer that acts as alpha blocker - vasodilation
Yohimbine: reversal agent for xylazine
Beta Blockers
Propranolol: treats cardiac arrythmias, HCM, decreases heart rate and cardiac output
Timolol: treats glaucoma
Tranquilizer - anxiolytic
Reduces anxiety
No analgesia
Acepromazine maleate
Chlorpromazine hydrochloride
Xylazine
Sedative - makes sleepy not necessarily anxiolytic
May provide some minor analgesia
Benzo: Diazepam, Midazolam, Alprazolam
Alpha-2: Xylazine, Dexmedetomidine
