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64 Cards in this Set
- Front
- Back
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L. stellate ganglia innervates what part of heart and has what effect on cardiac function
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posterior and lateral surfaces of both ventricles - increases ionotropy, increases map, no effect on hr
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R stellate ganglia innervates what part of heart and has what effect on heart function
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anterior epicardial surface and interventricular septum - increases HR and decreases diastolic time
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What chemical structures define a catecholamine
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a benzene ring with two attached hydroxyl groups and an amide containing side chain
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Order in which the catecholamines are produced
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phenylalanine ->tyrosine -> dopa -> dopamine -> NE -> Epi
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Effects of muscarinic stimulation on the body
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bradycardia, decreased ionotropy, bronchoconstriction, miosis (pupils small), incr secretion, incr go motility, incr gastric secretion
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Location of muscarinic receptors
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PNS post ganglionic junctions
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Location of nicotinic receptors
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SNS and PNS presynaptic junctions, skeletal muscle junctions
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Is the dominant effect of the ANS on the heart via PNS or SNS?
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SNS - maintains cardiac fcn at about 20% above that if there is an abscence of SNS function
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How does neostigmine effect Ach receptors? Which type of Ach receptors does it affect
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Neostigmine is a parasympathomimetic that acts as a reversible acetylcholinesterase inhibitor. It affects both nicotinic and muscarinic receptors. it is a quaternary amine so is polar and does not cross bbb into cns
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What type of Ach receptors does glycopyrrolate affect and how does it affect their function
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Glycopyrrolate blocks muscarinic receptors,thus inhibiting cholinergic transmission. It does not cross bbb as it is a quaternary amine
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How do α and β receptors in the pancreas affect insulin production
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α - decreases insulin production
β - increases insulin production β is bigger |
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How many paired sns ganglia are there and where do they originate
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22. They originate T1-T12 and L1-L3 in the gray intermediolateral column
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Are ANS postganglionic fibers myelinated or unmyelinated?
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unmeylinated. They conduct at slower speeds of < 2 m/s and similar to somatic C fibers
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Are ANS preganglionic fibers myelinated or unmyelinated?
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myelinated. are < 3mm in dia and conduct at 3-15 m/s.
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How does α1 fcn differ between peripheral resistance vessels and the GI tract
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constriction and relaxation respectively
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What is the general function of presynaptic α2 receptors
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mediates inhibition of NE release at synapse thereby serving as a negative feedback mechanism as α2 is itself affected by NE.
Centrally this actes to check and reduce sympathetic outflow. Peripharally |
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α1 and α2 function in coronary arteries
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α1 present in large epicardial arteries but these contribute to 5% of coronary resistance (so neo has little effect)
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α in myocardium
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positive ionotropic effect
- neo can incr contractility 2-3 fold (note that isoproteronal is a B agonist and it can increase contractility 6-7 fold) |
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How does α1 function in the failing heart? (especially in reference to B receptor fcn)
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In heart failure, there is a decrease in B receptor density, but not in α. Therefore α plays an increased role in pos inotropism but also plays a role in malignant arrythmia's
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How does α1 function in the failing heart? (especially in reference to B receptor fcn)
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In heart failure, there is a decrease in B receptor density, but not in α. Therefore α plays an increased role in pos inotropism but also plays a role in malignant arrythmia's
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β adrenergic receptors affect which intra-cellular signaling mechanism
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β -> induces adenyl cyclase which increases cAMP
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Where is β1 predominantly located?
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myocardium, sa node, ventricular conductionsystem
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Where is β2 located?
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skin, muscle, mesentery, bronchial smooth muscle, presynaptic junction, myocardium
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What is β2's major function
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stimulates vasodilation and bronchial relaxtion
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B1's major function
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inotropy and chronotropy
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What function do presynaptic β2 receptors have
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Enhand NE release (opposite of alpha2)
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Is β1 more sensitive to epi or NE?
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it is equally sensitive
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Is β2 more sensitive to epi or NE?
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Epi
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What is β1 and β2 function in kidney?
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β1 predominates. It causes renin release
β2 functions to regulate blood flow at vascular level |
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What is the dopamine(DA) effect on myocardium and are there specific DA receptors?
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Specific DA receptors have not been found, but DA activates β1 so incr hr and inotropism
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How and in what particular abdominal organs does DA and DA receptors act
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DA receptors most prominent in kidney and mesentary. DA causes vasodilation which increases blood flow.
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Outline DA function in CNS (3 areas)
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Hypothalmus - prolactin release
basal ganglia - coordinate motor function (degen in substantia nigra leads to parkinson chemoreceptor trigger zone in medulla - DA promotes N/V |
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Phenylephrine action on adrenergic receptors
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α1 +++++
α2 ? β1 +/- β2 0 |
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Norepinephrine action on adrenergic receptors
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α1 +++++
α2 +++++ β1 +++ β2 0 Only through central line to prevent necrosis |
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Epinephrine action on adrenergic receptors
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α1 +++++
α2 +++++ β1 ++++ β2 ++ Note: β2 action is big diff between NE & E, this action venodilates and produces more preload |
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Ephedrine action on adrenergic receptors
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α1 ++
α2 +++ β1 +++ β2 ++ Note: Most action due to indirecty. Causes release of NE. Has some direct. |
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Dopamine action on adrenergic receptors
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α1 + to ++++
α2 ? β1 ++++ β2 ++ DA1 +++ |
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Dobutamine actions on adrenergic receptors
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α1 0 to +
α2 ? β1 ++++ β2 ++ |
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Isoproteronol actions on adrenergic receptors
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α1 0 to +
α2 ? β1 ++++ β2 ++++ |
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What is clonidine's primary effect
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Partial α2 agonist (α2:α1 200:1) . Antihypertensive via central & peripheral attenuation of sympathetic outflow(.
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How does clonidine function centrally
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Stimulates α2 receptors in vaso motor centers of medulla oblongata -> decreases central sympathetic tone
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Problem and treatment of clonidine withdrawal
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Pay precitate hypertensive crisis. Treat with labetalol (β:α, 3:1 antagonist)
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Clonidine's use in epidural?
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Found to have dose-dependent analgesic. Can intensify block of regional, epidural, spinal.
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Clonidine's preop & periop use.
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1. blunts reflex tachy of intubation
2. reduces vasomotor lability 3. decreases catecholamine levels 4. decreases mac Side effect: sedation, dry mouth |
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How does dexmetomidine function
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Crosses BBB. alpha agonist α2:α1, 1600:1. It provides excellent sedation, reduces BP, reduces HR & catechole levels. also has analgesic effects Very little resp depression
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Dosing of decmetomindine
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Infusion at 0.1-0.7 μg/kg/hr. Can do loading doase of 1 μg/kg but watch out for hypotension
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How does dexmetomidine affect temperature
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increases range of temps that don't trigger thermoreg defenses. effective against post of shivering
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3 site of action of vasopressing
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1. renal collecting ducts
2. vascular smooth muscle 3. cardiact myocytes |
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In what abnl conditions is vasopressing particularly useful?
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hypoxia and acidosis
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How does vaso affect splancnic blood flow
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Constricts greater than peripheral.
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Milrinone acts how
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Phosphodiesterase inibitor. PDE's cause increase in cAMP by inhibiting it's break down. Increase cAMP causes increase in phosphorylation. In cardiac muscle this slows inward movement of calcium current, promoting intracellular Ca which increases inotropism. In Vasc smooth muslcle, incr cAmp causes vasodilationl
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Glucagon action (esp cardiac)
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1. Inhibits gastric motility
2. enhanced urinary excretion 3. Increased insulin secretion 4. Hepatic glycogenolsysis and gluconeogenesis 5. anorexia 6. inotropic and chronotropic effects. 7. relaxation of biliary smooth muscle |
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How are sympathomimetic amines' action affected in patients taking MAOI's?
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The action is potentiated
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Should you give a patient taking an MAOI (amitriptyline) meperidine?
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No, can cause hypertensive crisis
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What is the current guideline for periop management (stop, continue, etc.) of patients taking MAOI(amitriptyline)
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Pt's should stop taking MAOI at least 2 weeks prior to surgery.
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Name 4 non selective β-blockers
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propranolol, timolol, sotalol, timolol
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Name 3 β1 specific β-blockers
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Metoprolol, esmolol, atenolol
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What receptors does labetolol effect
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It is a mixed αβ antagonist (PO 1:3, IV 1:7). Used periop because it can drop BP and HR
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What CV effects do calcium channel blockers have?
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1. vasodilation
2. depressed cardiac conduction velocity 3. depress contractility 4. decrease HR. Note: Different CCB's do these 4 things diff so aren't interchangable. |
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How is verapamil useful?
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Useful in terminating Supraventricular tachydyssrhythmias. decreases nodal conductivity. also good for afib, aflutter Don't use with WPW
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In who should verapamil be avoided?
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wPW, sick sinus, heart failure
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What side effect must you watch for with verapamil?
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Can cause brady and cardiac colapse (especially in pt taking propranolol, digitalis)
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What might be observed in a patient if you treat a Duchenne's pt having a supravent tach with verapamil under GA
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Prolonged apnea and relaxation. because inhaled anes and ccb are additive. also ccb's augment depolarizing and non-depolarizing muscle relaxants
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Nicardipine acts to drop bp how
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It's a ccb that causes vasodilation of corornary and peripheral vessels. Doesn't have much affect on conduction velocity or depress myocardium
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