Autonomic Nervous System Flashcards
“Fight or Flight”
Sympathetic Nervous System
Stimulus for the SNS
Neurotransmitters
What is a stimulus?
Something to get it started
3 Neurotransmitters
- Norepinephrine
- Epinephrine
- Dopamine
What do the 3 neurotransmitters do to the SNS?
The 3 neurotransmitters get the SNS going and keep it going.
Where are norepinephrine and epinephrine located?
The adrenal gland.
Where does dopamine come from?
The brain. (Technically, everywhere)
What 3 items halt the stimulus?
- Re-uptake pump
- Enzymes
- Liver Metabolism
What are the 2 stopping (halting) enzymes?
- MAO (monoamine oxidase)
2. COMT
What do MAO and COMT do to the neurotransmitters?
They break down the neurotransmitters so they don’t work anymore.
How does the re-uptake pump halt the neurotransmitters?
The re-uptake pump brings the neurotransmitters back home.
How does liver metabolism halt the neurotransmitters?
When the neurotransmitters get to the liver, the liver breaks them down.
What would happen if there wasn’t a halt to the stimulus?
If nothing stopped the neurotransmitters the body would be on a high all the time.
SNS Receptors are _____ receptors?
Adrenergic Receptors
What do adrenergic receptors do?
They stimulate a sympathetic response.
What are the 4 adrenergic receptors?
- Alpha 1
- Alpha 2
- Beta 1
- Beta 2
Alpha 1 receptors are also known as?
Alpha blockers
How can the body respond to Alpha 1 receptors?
- Primarily smooth muscle contraction
- Vasoconstriction of coronary arteries
- Vasoconstriction of veins
- Decreased motility of smooth muscle of GI tract
- Glycogenolysis and gluconeogenesis from adipose tissue and liver
Do Alpha 1 receptors increase or decrease speed of the GI tract?
Decrease - no time to stop to go to the bathroom in fight or flight
What does a stimulus effect?
Receptors
What is gluconeogenesis?
Break down fat and glycogen for energy
Is the autonomic nervous system voluntary or involuntary?
involuntary
How can the body respond to Alpha 2 receptors?
- Primarily located at presynaptic ganglion
- Few drugs that impact these receptors
How can the body respond to Beta 1 receptors?
- Increase cardiac output
- Increase renin release in kidneys
Beta 1 receptors are known to effect what organ?
Heart
What is renin?
Renin is a vasoconstrictor
How can the body respond to Beta 2 receptors?
-Relax smooth muscles
(bronchi, urinary sphincters, bladder, uterus,
arteries)
-Contract GI sphincters
-Dilate arteries to skeletal muscles and cardiac muscle
-Increase renin from kidneys
What happens to vital signs if you constrict veins?
BP goes up and so does heart rate
Important Note:
Drugs can be selective OR activate multiple receptors.
Selective Receptors?
Only effect one receptor. (alpha 1 or beta 1 or beta 2)
Multiple Receptors?
May affect a lot, alphas and betas.
Older drugs: more general = more side effects
What do Adrenergic Agents do?
Stimulates sympathetic response.
Adrenergic Agents are also called?
Adrenergic Agonists
Sympathomimetics
Adrenergic Agents mechanism of action?
Stimulates sympathetic response, mimicking the sympathetic response
Adrenergic Agents Indications:
- Alpha 1: hypotension, nasal congestion
- Beta 1: cardiac arrest, heart failure, shock
- Beta 2: asthma, premature labor
In the Adrenergic Agents indications, Beta 1…
Beta 1 is used to stimulate the heart
In the Adrenergic Agents indications, Beta 2…
Relaxes smooth muscles in asthma and premature labor; this can relax the muscle that are contracting in the uterus
Adrenergic Agents Contraindications
- Known allergy
- Severe hypertension
Adrenergic Agents side effects and adverse effects in the CNS?
CNS: HA, restlessness, excitement, insomnia and euphoria
Hyped up
Adrenergic Agent side effects and adverse effects for cardiovascular?
CV: vasoconstriction, hypertension, tachycardia, palpitations, dysrhythmias
Palpitations - how the patient feels with a fast heart rate
Adrenergic Agent interactions
- Adrenergic blocking agents: reduced therapeutic effects
- Anesthetics: risk of cardiac dysrhythmias
- TCA: increased vasopresser effects: hypertension; respiratory depression
- MAO inhibitors: hypertensive crisis
What is TCA?
Tricyclic antidepressant
High blood pressure already
Adrenergic Blocking Agents are also know as?
Adrenergic antagonists and sympatholytics
Adrenergic Blocking Agents mechanism of action?
Blocking or preventing of sympathetic response
Blocking the receptors
Adrenergic Blocking Agents indications?
- Alpha 1 blockers: hypertension, BPH
- Beta 1 & 2 blockers: angina, hypertension, dysrhythmias, migraines, glaucoma
Angina - heart pain from constriction of arteries
Migraines - can be caused by vasoconstriction
Glaucoma - pressure in eye; dilating causes pressure
Adrenergic Blocking Agents contraindications?
- Alpha blockers: drug allergy, peripheral vascular disease, CAD, renal or liver disease
- Beta blockers: drug allergy, uncompensated heart failure, heart block or bradycardia, severe pulmonary disease
Bradycardia - you don’t want to slow the heart rate even more
If you have a rescue inhaler you don’t want to block the lungs
Adrenergic Blocking Agents side effects and adverse effects?
- Alpha blockers: based on vasculature
- Beta blockers: usually mild. May mask hypoglycemia. Angina or precipitate MI if withdrawn suddenly
Adrenergic Blocking Agents interactions?
- Adrenergic Agonists (epi, dopamine, etc) = decrease effects of each
- Other CV drugs, diuretics = potentiate effects = profound hypotension
- Anti-cholinergic and hypoglycemias = antagonistic effects
CV drugs if they do the same thing it could increase the effects
Adrenergic antagonist is…
Antagonist is “stronger” than the agonists
“Rest and Digest”
Parasympathetic Nervous System
What is the initiating stimulus in the PNS?
Imitating Stimulus: neurotransmitters
-Acetylcholine (Ach)
What is the halting stimulus in the PSN?
Halting stimulus: enzyme
- cholinesterase - breaks down Ach ( almost immediately )
PSN receptors?
Receptors: cholinergic receptors
- nicotinic - muscarinic
Cholinergic Agents are also known as?
Cholinergic agonists and parasympathomimetics
Parasympathomimetics - mimics the parasympathetic response
What do Cholinergic Agents do?
Stimulates the parasympathetic response
- Direct-acting = act on receptors
- Indirect-acting = increase available Ach by inhibiting cholinesterase; non-selective
What does cholinesterase do?
Cholinesterase breaks down Ach, so if I stop this, there is more Ach available = more of a parasympathetic response
Cholinergic Agents mechanism of action?
SLUDGE: salivation, lacrimation, urinary incontinence, diarrhea, GI cramps, and emesis
- Stimulate intestine and bladder
- Constriction of pupil (miosis), decrease IOP
- Constriction of bronchi and airways (you don’t need to breathe a lot)
Decrease IOP - constrict; most glaucoma eye drops are cholinergic
Cholinergic Agents indications?
- Reduce IOP
- Treat various GI and bladder disorders
- Diagnosis and treatment of myasthenia gravis (neuromuscular disease - muscle spasms)
- Treatment of Alzheimer’s disease
Cholinergic Agents contraindications?
Drug allergy, GI or GU obstruction, bradycardia (will just slow HR more), COPD (don’t want to constrict bronchioles), hypotension (will just relax more)
GI or GU obstruction = if you have an obstruction you don’t want to force it
Cholinergic Agents side effects and adverse effects?
Overstimulation if the PSNS
Ex) going to the bathroom All The Time
Cholinergic Agents interactions?
Anticholinergics, antihistamines and sympathomimetics = antagonistic effects = decrease response
Antihistamines and sympathomimetics do the opposite
What do Anti-Cholinergic Agents do?
Blocking the parasympathetic response
Anti-Cholinergic Agents are also known as?
Cholinergic blocking agents and parasympatholytics
Anti-Cholinergic Agents mechanism of action?
(Opposite of cholinergic)
- Pupils dilate (increase IOP - like at the eye doctor)
- Decrease in GI motility, GI secretions, and salivation
- Increase heart rate (sometimes)
- Decreased bladder contraction = urinary retention
- Reduce sweating; dry mucous membranes
- Prevents bronchial constriction
Anti-Cholinergic Agents indications?
(Anti-cholinergics)
- Decreasing muscle rigidity and diminish tremors
- Bradycardia
- Chronic bronchitis, exercise induced bronchospasms, COPD ( not because they open airways, but they prevent constriction)
- Irritable bowel disease and diarrhea
- Neurogenic bladder and incontinence
Anti-Cholinergic Agents contraindications?
Known drug allergy, narrow-angle glaucoma, acute asthma (rescue), myasthenia gravis, acute CV instability, GI or GU obstruction
Anti-Cholinergic Agents side effects and adverse effects?
Increased HR; CNS excitation, restlessness; increased IOP; dry mouth; constipation; urinary retention; decreased bronchial secretions.
Main side effect is DRYING!!!
Anti-Cholinergic Agents interactions?
Antihistamines, phenothiazines, TCA, MAOI’s = potentiate effects p
