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)
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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
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3
Q

Somatic PNS

A
  • Controls voluntary movement through skeletal muscle and mediation of involuntary reflexes
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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.
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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

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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
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7
Q

Adrenergic Receptors

A
  • These include alpha, beta, and dopamine receptors
  • Agonist means stimulator
  • Antagonist means inhibitor/blocker
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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
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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
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10
Q

Stimulation of PSNS

A
  • Stimulation produces cholinergic effects and blockages produce anticholinergic effects
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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
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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
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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
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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.
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15
Q

Alpha-2 Receptor

A
  • No therapeutic action on PNS but significant on CNS
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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
Q

Epinephrine Absolute Contraindication

A
  • 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
Q

Epinephrine use with caution

A
  • Hypertension, prostatic hypertrophy, pregnancy, diabetes mellitus
27
Q

Epinephrine Adverse Effects

A

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
Q

Norepinephrine (Levophed)

A
  • Catecholamine that has no effect on Beta 2
  • Limited clinical applications
  • Indicated in hypotensive states and cardiac arrest
  • Vasopressor (vasoconstrictor)
29
Q

Norepinephrine action

A
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
30
Q

Pharmacokinetics of Norepinephrine

A

Low dose - Evolving acute renal failure

Higher dose - Heart failure and shock

31
Q

Norepinephrine Administration

Contraindications

A
  • Continuous IV
  • Pheochromocytoma (tumor that produces epinephrine and norepinephrine)
  • Ventricular fibrillation (dangerous arrhythmia)
  • Other tachydysrhythmias
32
Q

Adverse Effects of Norepinephrine

A
  • Dysrhythmias
  • Tachycardia
  • Anginal pain
  • Necrosis if extravasation (infiltration)
33
Q

Albuterol (Proventil, Ventolin, Salbutamol)

A
  • 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
Q

Alpha Adrenergic Antagonist

A
  • 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
Q

Phentolamine (Regitine)

A
  • 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
Q

Beta-Adrenergic Antagonist

A
  • 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
Q

Beta-Adrenergic Antagonist

A
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
38
Q

Adverse Effects of Beta 1 Blockers

A
  • No Kidney Issues (All cardiac)
  • Bradycardia
  • Decreased cardiac output
  • Precipitation of heart failure
  • AV Heart block
  • Rebound cardiac excitation
39
Q

Metaprolol

A
  • 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.