Chapter 4: Nervous System Flashcards
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)
