Chapter 12: Cholinergic Drugs Affecting The Autonomic Nervous System - Pathophysiology Of PNS Flashcards
What is the Peripheral Nervous System (PNS)
Transmits signals between the CNS and the rest of the body
What are the two types of Neurons in the PNS
Motor Neurons: carry signals from the CNS that control the activities of muscles and glands
Sensory Neurons: carry signals to the CNS from the sensory organs
What part of the PNS controls voluntary movements by activating skeletal muscles?
Somatic Nervous System
What part of the PNS controls involuntary responses by influencing organs, glands and smooth muscle?
Autonomic Nervous system
What are the two divisions of the Autonomic Nervous System?
Sympathetic Division and the Parasympathetic Division
What is the Sympathetic Division of the ANS?
Prepares the body for stressful or energetic activity, “fight or flight”
What is the Parasympathetic Division of the ANS?
Dominates during times of “rest and digestion”, directs maintenance activities
What Type of receptors are associated with the sympathetic division of the ANS?
Adrenergic Receptors
What type of receptors are associated with the Parasympathetic Division of the ANS?
Cholinergic Receptors
What is the neurotransmitter for the parasympathetic nervous system?
Acetylcholine (ACH)
What parts of the body does ACH act on receptors?
- Mouth
- Eyes
- Bladder
- GI - Digestion
- Heart
- Lungs
What is the acronym to help you remember the effects of ACH on receptors in the different parts of the body>
- S: salivation and sweating (mouth)
- L: lacrimation (eyes)
- U: Urination (bladder)
- D: Diarrhea (GI)
- G: GI Distress (GI)
- E: Emesis (GI)
- D: Decreased HR (heart)
What is a Parasypathomimetic (Cholinergic drug)
- A drug that activates or mimics the Parasympathetic Nervous System
- will see an increase in effects (SLUDGED)
- Binds to Cholinergic receptors to produce the rest-and-digest response
- Inhibits the action of AChE
- High potential for serious adverse effects
What is the difference between a targeted effect and adverse effect of a parasympathomimetic?
Targeted effect is the expected therapeutic response from the medication and the rest would be Adverse effects
What can we use Parasympathomimetics for?
Myasthenia Gravis and Alzheimer’s disease
What is Myasthenia Gravis
Condition where the ACH receptors are damaged by an autoimmune mechanism which inhibits muscle contraction - for these patients parasympathomimetics act like ACH in some ways which increase the ability for the muscles to contract
Why can we use parasympathomimetics for Alzheimer’s disease>
In Alzheimer’s there is either a lack of ACH or damage to the receptors, parasympathomimetics Mimic ACH which is moderately helpful for these patients
What Other uses for parasympathomimetics other than Myasthenia Gravis and Alzheimer’s disease?
These uses logically flow form the effects of the drug
- Glaucoma (think pupillary constriction)
- Urinary retention (think of increased urination)
- Waking up the GI tract after surgery (stimulates digestion)
What are some contraindications of parasympathomimetics?
- Parkinson’s disease (imbalance in dopamine and ACH so increasing the activity of ACH will further that imbalance)
- BPH
- Peptic Ulcer disease (because of GI stimulation - leads to more HCI which we don’t want in peptic ulcer disease)
- Bradycardia (Because of decreased HR and contractility)
- Asthma (because of bronchoconstriction)
What do parasympatholytics do?
- Inhibit the action of ACH in some way
- Decreased SLUDGED
What are the effects of parasympatholytics?
- opposite of SLUDGED
- Dry Mouth
- Pupillary constriction
- Dry eyes
- Urinary retention
- Constipation
- Increased HR
- Bronchodilation.
Pneumonic for Anticholinergics
Can’t See
Can’t Pee
Can’t Spit
Can’t Poop
What are parasympatholytics used for?
- Parkinson’s disease - restore the balance between ACH and dopamine
- Anesthesia adjunct (decrease secretion - reduce aspiration during surgery)
- Eye Exams (ability to dilate the pupils)
- overactive bladder (will cause urinary retention)
- IBS and peptic ulcers (decreased digestion)
- Bradycardia (ability to increase the HR)
- Asthma/COPD (promotes bronchodilation)
What are contraindications for Parasympatholytics?
- Myasthenia Gravis (because we need ACH for this condition and parasympatholytics will decrease ACH)
- Glaucoma (pupillary dilation, can’t drain and increases the pressure)
- Urinary obstruction or BPH (already trying to reduce urination so would compound the obstruction disorders)
- GI obstructive disorders (because they slow down digestion and secretion)
- Cardiac Insufficiency (we don’t want to further decrease the hearts ability to work)
