Introduction to the Autonomic Nervous System

Autonomic Nervous System

- Regulates involuntary bodily functions automatically

- communicates with internal organs & glands

2 branches of the Autonomic Nervous System

- Sympathetic

- Parasympathetic

Sympathetic Branch

- arises from neurons in TS & LS

- Stimulates fight-or-flight response during stress.

Parasympathetic

Nervous system division promoting rest and digest.

Somatic Nervous System

Single neuron pathway from CNS to periphery.

Autonomic Nervous System

Two neuron pathway: preganglionic and postganglionic.

Preganglionic Neuron

First neuron from CNS, myelinated.

Postganglionic Neuron

Second neuron from autonomic ganglia, unmyelinated.

Synaptic Activity

Process of neurotransmitter release at synapse.

Neurotransmitter

Chemical messenger released into synaptic cleft.

Acetylcholine (Ach)

Primary neurotransmitter in parasympathetic system.

Norepinephrine (NE)

Primary neurotransmitter in sympathetic system.

Cholinergic Receptors

Receptors that bind acetylcholine.

Nicotinic Receptors

Cholinergic receptors at autonomic ganglia.

Muscarinic Receptors

Cholinergic receptors at effector cells.

Acetylcholinesterase (AchE)

Enzyme that breaks down acetylcholine.

Adrenergic Receptors

Receptors that bind norepinephrine.

Alpha Receptors

Adrenergic receptors involved in vasoconstriction.

Beta Receptors

Adrenergic receptors involved in various responses.

Alpha-1 Receptors

Cause contraction of vascular smooth muscle.

Alpha-2 Receptors

Inhibit norepinephrine release in CNS.

Beta-1 Receptors

Increase heart rate and contractility.

Beta-2 Receptors

Cause relaxation of bronchiole smooth muscle.

Cholinergic Medications

Increase activity at cholinergic synapses.

Fight or Flight

Sympathetic response preparing body for action.

Rest and Digest

Parasympathetic response promoting relaxation and digestion.

Neurotransmitter Removal

Inactivation via reuptake or metabolism.

Direct acting cholinergics

Agonists that activate cholinergic receptors.

Indirect acting cholinergics

Inhibit acetylcholine esterase, prolonging acetylcholine activity.

Glaucoma

Increased intraocular pressure leading to vision loss.

Aqueous humor accumulation

Excess fluid in the eye causing pressure.

Cholinergic agonists

Medications that increase aqueous humor flow.

Alzheimer's Dementia

Progressive disorder causing memory and cognition decline.

Cholinergic neuron degeneration

Loss of neurons essential for memory function.

Acetylcholinesterase inhibitors

Drugs that prolong acetylcholine activity in Alzheimer's.

Urinary Retention

Inability to void urine due to bladder atony.

Bladder atony

Lack of muscle tone in the bladder.

Myasthenia Gravis

Autoimmune disorder causing muscle weakness and fatigue.

nAchR antibodies

Autoantibodies blocking nicotinic acetylcholine receptors.

CNS toxicity

Delirium and hallucinations from anticholinergic drugs.

Neuromuscular blockade reversal

Restoration of muscle function after anticholinergic effects.

Smooth muscle contraction

Stimulated by cholinergic agonists in the bladder.

AchE

Enzyme that breaks down acetylcholine.

Synaptic cleft

Space between neurons where neurotransmitters act.

General Anesthesia

Uses NMJ blockers for muscle paralysis during surgery.

Skeletal Muscle Paralysis

Temporary loss of muscle function during surgery.

Acetylcholinesterase Inhibitor

Reverses neuromuscular block by increasing Ach levels.

Direct-Acting Cholinergics

Agonists that stimulate cholinergic receptors directly.

Bethanechol

M1, M2, M3 agonist for urinary retention.

Isopto Carbachol

Ophthalmic solution for glaucoma treatment.

Carbachol

Agonist for mAchR and nAchR receptors.

Pilocarpine

M3 agonist used for glaucoma treatment.

Pyridostigmine

Oral medication for myasthenia gravis treatment.

Physostigmine

Discontinued drug for glaucoma and CNS toxicity.

Donepezil

Oral drug for Alzheimer's dementia management.

Rivastigmine

Transdermal patch for Alzheimer's and dementia.

Neostigmine

IV drug for urinary retention treatment.

Reversible AchE Inhibitors

Drugs that temporarily inhibit acetylcholinesterase.

Organophosphates

Irreversible AchE inhibitors found in pesticides.

Cholinergic Medications

Stimulate parasympathetic nervous system effects.

SLUDGE-BAM

Acronym for cholinergic effects: Salivation, Lacrimation, etc.

Anticholinergic Medications

Block activity at cholinergic synapses.

Competitive Antagonists

Drugs that inhibit receptor activity by competing.

Antimuscarinic Drugs

Block muscarinic receptors to reduce cholinergic effects.

Adverse Effects of Cholinergics

Include nausea, vomiting, diarrhea, and bronchoconstriction.

Bronchoconstriction

Narrowing of airways due to cholinergic stimulation.

Bradycardia

Slowed heart rate as a cholinergic effect.

Antinicotinic drugs

Block nicotinic receptors (nAchRs) in the body.

Anticholinergics

Drugs that inhibit cholinergic synapse activity.

Peptic ulcer

Condition treated by reducing gastric acid production.

Irritable bowel syndrome

Condition managed by decreasing smooth muscle spasms.

Parkinson's disease

Loss of dopamine leads to cholinergic hyperactivity.

Bradycardia

Slow heart rate, treated with anticholinergics.

Motion sickness

Condition treated by blocking cholinergic transmission.

Preoperative medication

Used to decrease respiratory secretions during anesthesia.

Urinary incontinence

Condition treated by reducing bladder contractions.

Bronchodilation

Relaxation of bronchial smooth muscle for asthma treatment.

Mydriasis

Pupil dilation caused by blocking Ach-mediated contraction.

Cholinergic poisoning

Caused by mushrooms or pesticides, life-threatening.

Atropine

Antidote for cholinesterase inhibitor poisoning.

Benztropine

Used for Parkinson's and antipsychotic side effects.

Dicyclomine

Treats irritable bowel syndrome and preoperative conditions.

Glycopyrrolate

Reduces secretions and bladder hypermotility.

Ipratropium

Bronchodilator for asthma and COPD.

Oxybutynin

Treats overactive bladder and urinary frequency.

Scopolamine

Used for motion sickness and antivertigo.

Tiotropium

Long-acting bronchodilator for COPD.

Tolterodine

Treats overactive bladder symptoms.

Dry mouth

Common side effect of anticholinergic drugs.

Urinary retention

Inability to urinate, a side effect of anticholinergics.

Constipation

Reduced intestinal motility due to anticholinergics.

Reflex bradycardia

Compensatory response to increased blood pressure.

Orthostatic hypotension

Significant blood pressure drop upon standing.

Alpha-1 receptor

Smooth muscle receptor causing vasoconstriction when stimulated.

Phenylephrine

Nasal decongestant acting as an alpha-1 agonist.

Prazosin

Alpha-1 antagonist for hypertension and PTSD nightmares.

Clonidine

Alpha-2 agonist used for hypertension.

Dobutamine

Beta-1 agonist for cardiac decompensation.

Atenolol

Selective beta-1 blocker for hypertension and angina.

Albuterol

Beta-2 agonist for asthma and COPD.