30 Questions
What is the effect of stimulating α2-receptors on blood pressure?
Decrease
What is the effect of β2 receptors on respiratory smooth muscle?
Relaxation
What is the effect of dopamine on heart rate at low doses?
Decrease
What is the primary mechanism of epinephrine's effect on coronary blood flow?
Increased myocardial oxygen demand
What is the primary effect of β1-receptors on the heart?
Positive chronotropy and inotropy
What is the half-life of elimination of epinephrine?
< 5 minutes
What is the effect of norepinephrine on heart rate?
Maintained
What is the primary mechanism of dopamine's indirect effects?
Release of norepinephrine
What is the effect of isoproterenol on myocardial O2 supply?
Decreased
What is the primary effect of dobutamine on the heart?
Increased coronary blood flow
What is the mechanism of norepinephrine's vasoconstrictor effect?
Activation of α1 receptors
What is the effect of dopamine on peripheral vascular resistance at high doses?
Increased
What is the primary effect of β1 agonists on the heart?
Increase cardiac contractility
What is the mechanism of action of ephedrine?
Indirect β agonist and direct α agonist
What is the primary effect of phenylephrine on the heart?
Decrease heart rate
What is the primary mechanism of action of phentolamine?
Competitive and nonselective α antagonist
What is the typical dose range for dopamine infusion?
0.5-1 mcg/kg/min
What is the primary use of phenylephrine nasal drops/spray?
To vasoconstrict nares prior to nasal intubation
What is the primary effect of phenoxybenzamine on blood pressure?
It causes a decrease in blood pressure
What is the main use of yohimbine?
Treatment of orthostatic hypotension
What is the FDA warning associated with droperidol?
Prolonged QT interval
What is the effect of clonidine on heart rate?
It decreases heart rate in a dose-dependent manner
What is the main mechanism of action of dexmedetomidine?
It is a selective presynaptic α2 agonist
What is the effect of phenoxybenzamine on insulin secretion?
It increases insulin secretion
What is the primary indication for initiating β blockade preoperatively?
Vascular and intermediate-risk surgical procedures
What is the primary advantage of using cardioselective β blockers?
They are more selective for β1 receptors
What is the effect of β blockers on the sympathetic nervous system?
Decrease sympathetic nervous system activity
What is the dose of esmolol for controlling heart rate?
10-20 mg initial and titrate to goal HR
What is the mechanism of labetalol's action?
Non-selective β and α1 antagonist
What is the antidote for β blocker overdose?
Glucagon 5 mg IV
This quiz covers the effects of beta receptors on heart rate, blood pressure, and other physiological processes. Learn about the functions of beta 1, 2, and 3 receptors and their roles in various bodily systems.
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