12.1 Autonomic and CNS Flashcards
1
Q
Central Nervous System
A
- Consists of brain and spinal cord
- Brain is the main functional unit
- Spinal cord is main processing unit (movement/reflex)
2
Q
Peripheral Nervous Syste
A
- Split into afferent and efferent
Afferent - Sensory neurons that carry sensory information towards the CNS
Efferent - Motor neurons that carry impulses from CNS to muscles to produce movement - Also divided into Somatic and Autonomic
3
Q
Somatic PNS
A
- Controls voluntary movement through skeletal muscle and mediation of involuntary reflexes
4
Q
Autonomic Nervous System (cont)
A
- Controls involuntary activities in smooth muscle, secretory glands, and visceral organs.
- Functions for homeostasis, stress response, and body tissue repair.
- Acetylcholine and norepinephrine are the major neurotransmitters for ANS.
5
Q
Autonomic Nervous System (ANS)
A
Divided into Parasympathetic Nervous System (PSNS) and Sympathetic Nervous System (SNS)
Sympathetic - Fight or Flight Response preparing the body for intense physical activity
Parasympathetic - Relaxes body and inhibits/slows many functions
6
Q
Physiological Effects of SNS
A
- Increase heart rate, arterial blood pressure and cardiac output
- Increased blood glucose, pupillary dilation, rate of cellular metabolism
- Increased blood flow to brain, heart, skeletal muscles
- Increased rate/depth of respiration
7
Q
Adrenergic Receptors
A
- These include alpha, beta, and dopamine receptors
- Agonist means stimulator
- Antagonist means inhibitor/blocker
8
Q
Stimulation of SNS Receptors
A
- Stimulation of SNS receptors produces adrenergic effects and blockage produces antiadrenergic effects
- Stimulation of SNS receptors produces adrenaline effects on the body
9
Q
Physiological Effects of PSNS
A
- Dilation of blood vessels in the skin
- Decreased heart rate
- Increased secretion of digestive enzymes
- Pupillary constriction
- Contraction of smooth muscle in bladder
- Contraction of skeletal muscle
10
Q
Stimulation of PSNS
A
- Stimulation produces cholinergic effects and blockages produce anticholinergic effects
11
Q
Catecholamines (adrenergic agonist)
A
- Contain catechol and an amine group
- Can be nonselective (alpha and beta receptors) or selective
- Short duration
- Cannot be given orally
- Does not cross BBB
- Destroyed by COMT and MAO located in liver and intestinal wall
- Examples include dopamine, dobutamine, epinephrine, isoproterenol, norepinephrine
12
Q
Non-Catecholamines
A
- Activates alpha and beta receptors
- Poor affinity so poorly selective
- Long duration
- Can be given orally
- Does not cross BBB
- Destroyed only by MAO so longer half-life
- Examples clonidine, ephedrine, respiratory drugs, mephentermine
13
Q
Alpha-1 Adrenergic Receptors
A
- Vasoconstriction and Mydriasis (Pupil Dilation)
- Homeostasis of skin and mucous membranes (usually topical epinephrine)
- Supplements anesthesia; delays absorption to prolong anesthesia, usually epinephrine
- Hypotension when fluid replacement and other measures fail
- Mydriasis to facilitate eye exam or ocular surgery
14
Q
Alpha-1 Adrenergic Receptors Adverse Effects
A
- Hypertension due to vasoconstriction
- Necrosis due to vasoconstriction locally
- Reflex bradycardia - Increased blood pressure stimulates baroreceptors leading to bradycardia. This can compromise tissue perfusion in people with diminished cardiac reserve.
15
Q
Alpha-2 Receptor
A
- No therapeutic action on PNS but significant on CNS
16
Q
Beta-1 Adrenergic Receptor
A
- Initiates contractions in cardiac arrest patients
- Positive inotropic effects on heart failure
- Increased HR and contractility in heart failure patients
- Enhances impulses through AV node in Heart Block
17
Q
Adverse effects of Beta-1 Adrenergic Receptors
A
- Altered HR and rhythm
- Angina (Ischemic chest pain) in patients with compromised coronary circulation (supplies blood to the heart)
18
Q
Beta-2 Adrenergic Receptors
A
- Used to help with asthma, preferred especially in patients with cardiac disease
19
Q
Beta-2 Adrenergic Receptors Adverse Effects
A
- Hyperglycemia due to stimulation of liver and skeletal muscle beta 2 receptors leading to breakdown of glycogen to glucose
- Tremors due to contractions of skeletal muscle
20
Q
Dopamine Receptors
A
- Improved renal perfusion (dilation of kidney vasculature)
Adverse Effects - Dose dependent but include tachycardia and necrosis with extravasation.
21
Q
Epinephrine (Adrenaline)
A
- Catecholamine (non selective) adrenergic agonist
- Acts on alpha 1,2 Beta 1,2
- Positive inotropic (increases strength of contractions)
- Positive chronotropic (increases heart rate)
22
Q
Epinephrine Pharmacotherapeutics
A
- Alpha 1 for vasoconstriction (controls bleeding and helpful with local anesthesia) also dilates pupils (mydriasis)
- Beta 1 for contractility of heart used for AV heart block and cardiac arrest
- Beta 2 for bronchodilation but other drugs more preferred (selective beta-2)
- Combination of alpha and beta are good for anaphylactic shock (severe allergic reaction)
23
Q
Epinephrine Pharmacotherapeutics
A
- Stimulates adrenergic receptors directly
- Positive inotropic and chronotropic effects on myocardium
- Vasoconstriction of skin and viscera
- Vasodilation of skeletal muscles
- Increased systolic BP
- Bronchodilation
24
Q
Epinephrine Pharmacokinetics
A
- Parental, Topical and Inhalation
- Rapid Absorption (IV and Inhalation) - Instant
(Duration is 20-30 min) - Slower (SubQ) - Less than an hour
(Duration is 4 hours) - Inactivated by COMT and MAO with update by adrenergic nerves so short duration.
- Excreted in kidneys
25
Epinephrine Absolute Contraindication
- Sulphite Sensitivity
- Closed-angle glaucoma
- Labor (delays labor)
- Severe cardiac disease (increased oxygen demand, increased HR)
- Shock states other than anaphylactic
- Patients receiving general anesthesia
- Cerebrovascular disease (hemorrhage)
- Can worsen hypertension
- Can cause cardiotoxicity symptoms in hyperthyroid patients
26
Epinephrine use with caution
- Hypertension, prostatic hypertrophy, pregnancy, diabetes mellitus
27
Epinephrine Adverse Effects
Common - Tremors, weakness, dizziness, anxiety, pallor, palpitations, apprehensiveness, sweating, nausea, vomiting
Severe - Hypertensive crisis, angina, cerebral hemorrhage, cardiac dysrhythmias, necrosis (IV site)
Hyperthyroid/Hypertensive patients
Patients with DM (hyperglycemia)
28
Norepinephrine (Levophed)
- Catecholamine that has no effect on Beta 2
- Limited clinical applications
- Indicated in hypotensive states and cardiac arrest
- Vasopressor (vasoconstrictor)
29
Norepinephrine action
```
Low dose (2mcg/kg/min) - Only dopamine
Vasodilates kidneys, and GI Tract to lower BP
Moderate dose - Beta 1
Vasoconstricts - increase BP and reduce blood flow to kidneys. Cuts down blood to peripherals and causes pale extremities
High dose - Alpha 1
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30
Pharmacokinetics of Norepinephrine
Low dose - Evolving acute renal failure
| Higher dose - Heart failure and shock
31
Norepinephrine Administration
| Contraindications
- Continuous IV
- Pheochromocytoma (tumor that produces epinephrine and norepinephrine)
- Ventricular fibrillation (dangerous arrhythmia)
- Other tachydysrhythmias
32
Adverse Effects of Norepinephrine
- Dysrhythmias
- Tachycardia
- Anginal pain
- Necrosis if extravasation (infiltration)
33
Albuterol (Proventil, Ventolin, Salbutamol)
- Beta 2 Agonist - relaxes bronchial smooth muscle
- Used for asthma, bronchospasm, bronchitis, COPD, and other reversible bronchoconstriction's
- Contraindications (cardiac disease and hypertension)
- Adverse Effects (Tremor, dizziness, nervousness, restlessness, tachycardia, palpations)
- Administration (PO, Inhalation)
- Antidote (Propranolol)
34
Alpha Adrenergic Antagonist
- Vasodilator for hypertension
- Reverse alpha-1 agonist toxicity
- Used for Pheochromocytoma (catecholamine secreting tumor used to suppress hypertension)
- Raynaud's disease - Vasospastic disorder primarily of fingers and toes. Prevent alpha mediated vasoconstriction
- Adverse Effects - Orthostatic hypotension, reflex tachycardia, nasal congestion
35
Phentolamine (Regitine)
- Alpha 1 and 2 adrenergic antagonist
- Prevention of tissue necrosis from alpha-1 mediated vasoconstriction.
- Used for hypertensive patients with pheochromocytoma
- Adverse Effects
- Orthostatic hypotension, reflex tachycardia, nasal congestion
- IV or IM one or two hours prior.
36
Beta-Adrenergic Antagonist
- Reducing HR, force of contractions.
First generation - non selective block both beta 1 and beta 2 receptors (propranolol - Inderal)
Second generation - Cardio selective, only block beta 1
(metoprolol - Lopressor)
Third generation - Vasodilates, produces non-selective or cardio selective effects. (carvedilol - Coreg)
37
Beta-Adrenergic Antagonist
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Angina - Decreases work of heart
HTN - Very good for hypertension
MI - Reduce pain and reinfarction risk
HF - Standard therapy
Hyperthyroidism
Migraine - Reduces frequency
Stage Fright - Prevents Beta-1 blockers mediated tachycardia
Glaucoma - Treats intraocular pressure
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38
Adverse Effects of Beta 1 Blockers
- No Kidney Issues (All cardiac)
- Bradycardia
- Decreased cardiac output
- Precipitation of heart failure
- AV Heart block
- Rebound cardiac excitation
39
Metaprolol
- Second generation (cardioselective) beta blocker
- Only block beta 1 at low doses but block both beta 1 and 2 at higher doses
- Used for hypertension primarily, and angina pectoris, heart failure, and MI
- Reduces HR, force of contraction, and AV impulse conduction. Net effect decreases cardiac output. Renal beta-1 also suppresses renin secretion.
Adverse effects - Bradycardia, AV heart block, heart failure,.
Contraindication - AV Heart Block, sinus bradycardia, use cautiously with heart failure.
