NS Flashcards
Peripheral NS includes
Motor Neurons and senosry neruons
Motor breaks into somatic and autonomic
Autono ic breaks into sympathetic and parasympathetic
Sympathetic NS has which type of receptors
Adrenergic
Alpha and Beta
Parasympathetic division has which receptors
Cholinergic receptors
Muscarinic
Function of PNS
Recognize changes in the internal and external environment
Relies on receptors that respond to different sensory modalities
React to environmental changes by producing an action or response
Parasympathetic neurons originate from
Cranial nerves and sacral spinal cord
Symp neurons originate from
Neurons originate from the thoracic and lumbar spinal cord
Target tissues of NS ar
Organs and glands
Homeostais is achieved
Achieved by changing tone of one or both branches
Tone is achieved by
Increasing or decreasing the firing of sympathetic nerves
Increasing or decreasing the firing of parasympathetic nerves
Two neuron chain
Preganglionic neuron
Originate inside of CNS
Postganglionic neuron
Originate outside of CNS
Ganglion
A grouping of neuron cells bodies
In ANS, cell bodies are those of postganglionic neurons
Neuroeffector junction
A specialized synapse on which a postganglionic neuron terminates onto a target tissue (muscle or gland)
Two primary ANS NTs are
NE and ACh
Storage of the neurotransmitter
Millions of granules or vesicles at the terminal ends of each axon
Release of the neurotransmitter
At end of axon, action potential stimulates some vesicles to release their stored neurotransmitters into the synapse
General Mechanisms of ANS Drugs (2 of 2)
Bind to the neurotransmitter receptor site on the postganglionic nerve
Prevent the normal destruction or reuptake of the neurotransmitter
Prolonged
Cholinergic Receptors (Respond to Ach)
ParaSympathetic
Includes Nicotinic and Musscarinic
Nicotinic receptors
Found on postganglionic neurons in ANS
Promotes sympathetic and parasympathetic effects
Found at neuromuscular junction of skeletal muscle cells
Muscarinic
Found on parasympathetic target tissues
Promotes parasympathetic effects
Alpha and beta adrenergic receptors are found where, and what NT do they respond to?
Found on target tissues of sympathetic nervous system
Promotes sympathetic effects
Respond to catecholamine neurotransmitters such as norepinephrine (NE) and epinephrine
Drugs that Stimulation of sympathetic nervous system
Adrenergics, sympathomimetics, adrenergic agonists
Produce fight-or-flight response
ANS drugs classed based on four [ossible actions
Stimulation of sympathetic nervous system
Inhibition of the sympathetic nervous system
Stimulation of parasympathetic nervous system
Inhibition of the parasympathetic nervous system
Drugs causing inhib of Symp NS
Adrenergic antagonists, antiadrenergic, adrenergic blockers
Produce actions opposite to adrenergics
Drugs stimulaing Parasymp NS
Cholinergics, parasympathomimetics, muscarinic agonists
Produce rest-and-digest response
Inhin of parasymp NS
Anticholinergics, parasympatholytics, muscarinic blockers
Produce actions opposite to those of the cholinergics
Cholinergics are rarely used due to
Severe effects
SLUDGE
SLUDGE
Excessive salivation
Excessive lacrimation
Urinary incontinence
Diarrhea
GI Cramps
Emesis
Cholinergics are contrindicate in asthma
bc they constrict bronchiles
Anticholinergics
Drugs that block or inhibit the actions of ACh in the parasupathetic NS
Anticholinergics mech of action
Competitive antagonists
Compete with Acetylcholine (Ach)
Block ACh at the muscarinic receptors in the PSNS
As a result, ACh is unable to bind to thereceptor site and cause a cholinergic effect
Once these drugs bind to receptors, they inhibit nerve transmission at these receptors
Drug effect for Anticholinergic agents
Cardiac Rhythm Abnormalities
Increase HR in bradycardia
CNA
Reduce Muscle tremor
GI disorders
decrease gastric acid secretion in peptic ulcer disease
Slow intensinal motility
Pre anethetis
Anticholinerigic effect on GI d
GI disorders
decrese the secretion of gasric acid.
slow intestinal motility
Antichoinergics cardiac affect
ACClerate HR
Pre anethia use of anticholinergic
In combo with other meds Decrease resp secretions and reverse bardycadia
What is atropine
the antidote for cholinergic drugs
It should be available for immediate use if needed
Adrenergic
Drugs in this class include naturally occurring substances such as norepinephrine, epinephrine, and dopamine.
Norepinephrine (NE) is the major neurotransmitter.
Dopamine is a key neurotransmitter in the CNS.
Contraindications for Cholinergic antagonsits
Acute angle galcuoma
Heart conditions
Hyperthyroid
Renal conditions
Gerd
Ulcer colitis
Paralytic iileus
Adrenergic receptors with two subtypes Beta and Alpha
Alpha 1 and Alpha 2
Beta 1 and Beta 2
Beta 1 adrenergic recpetors located primarrily in
The heart
Beta2 adrenergic recepots located primarliy in the
smooth muscle of bronchioles
Conditions treated by adrenergic agonsits
Alpha 1- nasal congestion, hypotension, and mydriasis.
Alpha 2- Hypertension
Beta 1- cardiac arrest, heart failure and shock. Sometimes called cardiotonic or inotropic because they increase the force of contraction of the heart
Beta 2- Asthma - relaxation of bronchial smooth muscle (bronchodilators)
Side effects of adrenergic drugs le epinephrine
Severe CV effects (Tachycardia or HTN)
Prototype- Phenylephrine
Adrenergic Agonist
Selective only affects the alpha1 receptors
Used during hypotension or for nasal congestion
Has few cardiac side effects
Adrenergic Antagonists (Blockers)
Medications in this class have great therapeutic application and are the most widely prescribed autonomic drug. Mainly used for hypertension.
Bind to adrenergic receptors, but inhibit or block stimulation of the SNS ___________
Beta-blockers and Alpha-blockers
Have the opposite effect of adrenergic agents
AKA
Adrenergic antagonists
Sympatholytics
Adverse effects of alpha-blockers
Ortho HOTN
Especially a risk at begiing of treatment, this is called the first dose phenomenon
Beta-Blockers
May block stimulation of both beta-1 or 2 or both receptors in the SNS
Most common blood pressure medications
Eg after next slide
Beta 1 receptors
Located primarily on the heart
Beta-blockers selective for these receptors are called cardioselective beta-blockers
Beta 2 Receptors
Located primarily on smooth muscles of bronchioles and blood vessels
Nonspecific Beta-blockers block both
beta1- and beta2-receptors
Do we give non sspecigic beta blocker to ashma
No
What type of receptors does ACh bind to?
Muscarinic and Nicotinic
Most common action of beta blockers
Decreased HR and BP
How to prevent HOTN when use beta blockers
Check BP and HR before giving medication
Beta blockers may cause (secondary adverse effects)
Diarrhea
Stomach cramps
Nausea
Vomiting
Steps in a synaptic transmission
SC, Preganglionic Neuron, Postgnaglionic neuron (Autonomic gnaglionn), Effector
Where are NTs synthesized?
In the cell body or axon terminal of neruon
How are NT removed from synapse?
Degraded in synaptic cleft by enzymes
Ach degraded by acetylcholinesterase (AchE)
NE degraded by catechol-o-methyl transferase (COMT) in synapse
Reuptake back into presynaptic neuron
How do muscarinic receptors respond to ACh?
Target tissues in PNS
Constricts pupils, decreases HR, constricts bronchi, increases GI motility and secretions
What receptors does NE bind to?
Alpha 1
Alpha 2
Beta 1
Beta 2
Alpha 1 receptor binding
Constricts arterioles, dilates pupils
Alpha 2 receptor binding
Decreases tone of SNS
Beta 1 receptor binding
Increases HR and force of contraction of heart
Beta 2 Receptor binding
Dilates bronchi, dilates arterioles to skeletal muscles
Drugs that stimulate the sympathetic nervous system receptors are called
sympathomimetics or adrenergic agonists. They produce classic symptoms of the fight or flight response
Inhibition of the SNS drugs are called
Adrenergic blockers
opposte to adrenergics
Drugs that stimulate the parasympathetic nervous system
These drugs are called cholinergics, Parasympathomimetics or muscarinic agonists. They produce the characteristic symptoms of the rest-and-digest response
Mimic effect of ACh
Inhibition of the PNS drugs are called
anticholinergics
parasympatholytics or muscarinic blockers. They produce actions opposite to cholinergics.
Parasympoathomimetics AKA
Cholinergic agonists
Acetycholine NT
Stimulates or activates the next nerve cell as impulses move along a nerve from neuron to neuron or at the neural muscular junction stimulating muscle stimulation
Uses for cholenergics
Promotion of bladder motility
Promotion of GI motility
Treatment of glaucoma
Where are Beta 1 and 2 Receptors Located?
Beta1-adrenergic receptors—located primarily in the heart
Beta2-adrenergic receptors—located in smooth muscle of the bronchioles, arterioles, and visceral organs
