Valley Quiz - PERIPHERAL NERVOUS SYSTEM

Question 1

Esmolol (Brevibloc) works primarily by competitively antagonizing what adrenergic receptor(s)?
a.  Alpha l
b. Beta 1
C. Beta 2
d. Alpha 1, Beta 1

Answer 1

b. Beta 1

Question 2

Postsynaptic nicotinic receptors are found at each of the following sites EXCEPT:

a. adrenal medulla.
b. sinoatrial node.
c. autonomic ganglia.
d. skeletal muscle motor end-plate.

Answer 2

B sinoatrial node

Question 3

The effects of norepinephrine released from sympathetic postganglionic neurons are terminated mainly by

a. metabolism by MAO in the synaptic cleft.
b. metabolism by COMT in the synaptic cleft.
c. diffusion from the synaptic cleft into the blood stream.
d. reuptake by the nerve terminal.

Answer 3

D reuptake by the nerve terminal.

Question 4

Release of neurotransmitter requires the entry of what substance into the nerve terminal?

a. Sodium
b. Potassium
c. Magnesium
d. Calcium

Answer 4

D Calcium

Question 5

Which agonist listed below is largely devoid of beta2-adrenergic activity?

a. lsoproterenol
b. Terbutaline
c. Epinephrine
d. Norepinephrine

Answer 5

D Norepinephrine

Question 6

The effects of ephedrine are due mostly to its

a. stimulation of the nerve terminal to release norepinephrine.
b. direct stimulation of a 1 and a 2 receptors.
c. direct stimulation of B1 and B2 receptors.
d. direct stimulation of a1, B1 and B2 receptors.

Answer 6

A stimulation of the nerve terminal to release norepinephrine.

Question 7

Low levels of circulating epinephrine cause

a. a reflex decrease in heart rate.
b. a decrease in systolic blood pressure.
c. a decrease in systemic vascular resistance.
d. an increase in diastolic blood pressure.

Answer 7

C a decrease in systemic vascular resistance.

Question 8

A patient chronically taking propranolol for hypertension is to undergo anesthesia and surgery. His last dose of propranolol was two hours before surgery. During the case, you would be cautious about
administering which of the following drugs?
a. Furosemide
b. Phenylephrine
c. Nitroglycerin
d. Hydralazine

Answer 8

B Phenylephrine

Question 9

In the patient who is chronically beta-blocked, the beta receptors

a. increase in number.
b. decrease in number.
c. become hypersensitive to beta-adrenergic agonists.
d. become insensitive to beta-adrenergic agonists.

Answer 9

A increase in number. (UP REGULATION)

Question 10

Alpha-adrenergic receptor blockade produces

a. an increase in systemic vascular resistance.
b. bronchoconstriction.
c. venodilation and a decrease in venous return.
d. an increase in heart rate.

Answer 10

C Venodilation and a decrease in venous return.

Question 11

You would consider avoiding which of the following adrenergic antagonists in the asthmatic?

a. Labetalol
b. Esmolol
c. Yohimbine
d. Phentolamine

Answer 11

A Labetalol

Question 12

Which intravenous general anesthetic would you most avoid in the beta-blocked patient?

a. Methohexital
b. Alfentanil
c. Ketamine
d. Propofol

Answer 12

C Ketamine

Question 13

A farmer who one hour ago was spraying his crops with organophosphate insecticide complains of
abdominal cramps, muscle weakness, and blurred vision. He is wheezing and bradycardic. Treatment
of this condition might reasonably include each of the following agents EXCEPT:
a. physostigmine.
b. atropine.
c. diazepam.
d. pralidoxime.

Answer 13

A physostigmine

Question 14

Which second messenger promotes bronchoconstriction?

a. Cyclic guanosine monophosphate (cGMP)
b. Inositol triphosphate (IP 3)
c. Cyclic adenosine monophosphate (cAMP)
d. Calmodulin

Answer 14

B inositol triphosphate (IP 3)

Question 15

Which of the following agents produces the greatest increase in heart rate?

a. Scopolamine
b. Glycopyrrolate
c. Atropine
d. Pilocarpine

Answer 15

C Atropine

Question 16

Proprioception is carried by

a. A-alpha fibers
b. A-gamma fibers
c. A-delta fibers
d. dC fibers

Answer 16

A A-alpha fibers

Question 17

Insulin receptors contain an active tyrosine kinase domain. What is the function of a kinase?

a. Kinases exchange GTP for GDP
b. Kinases activate calcium channels on the endoplasmic reticulum
c. Kinases catalyze the addition of a phosphate group to a substrate
d. Kinases degrade cyclic nucleotides (cAMP, cGMP) to inactive products

Answer 17

C Kinases catalyze the addition of a phosphate group to a substrate

Question 18

The cell bodies (soma) of which of the following structures lie in brainstem and sacral cord areas?

a. postganglionic sympathetic nerves
b. preganglionic sympathetic nerves
c. postganglionic parasympathetic nerves
d. preganglionic parasympathetic nerves

Answer 18

D preganglionic parasympathetic nerves

Question 19

Which of the following structures is not innervated by the stellate ganglia?

a. bronchioles
b. pupils
c. eyelids
d. nasal vasculature

Answer 19

A bronchioles

Question 20

The substrate for phoshpolipase C (PLC) is:

a. inositol triphosphate
b. diacylglycerol
c. phosphatidylinositol-4,5-bisphosphate
d. caclium

Answer 20

C

c. phosphatidylinositol-4,5-bisphosphate

Question 21

The compatibility of general intravenous anesthetics and volatile agents with beta-adrenergic receptor
antagonists. Anesthetics are ranked from those with the least favorable interaction with
beta-blockers to those with the most favorable interaction :

Answer 21

Ketamine
Enflurane
Halothane
Opioids
(isoflurane = sevoflurane = desflurane)

Question 22

Your patient has been treated with an MAO inhibitor for depression. General anesthesia is planned for
a ruptured appendix.

a. What drug will you most avoid using in this patient?
b. What other drug might you also want to avoid using? .

Answer 22

Meperidine (Demerol)

Ephedrine

Question 23

Your OB patient is given ritodrine for her premature labor.
a. What kind of drug is ritodrine?

b. What are three side-effects of ritodrine?
i. Hyperglycemia or hypoglycemia?
ii. Hyperkalemia or hypokalemia?
iii. Tachycardia or bradycardia?

Answer 23

a. Ritodrine is a tocolytic, meaning it relaxes the pregnant uterus. More specifically, ritodrine is a
beta-2 adrenergic receptor agonist.

b i. hyperglycemia

bii. hypokalemia
biii. tachycardia

Question 24

Your OB patient becomes hypotensive and needs a vasopressor.

a. What agent may be best in this situation? Ephedrine or phenylephrine
b. Why?

Answer 24

Ephedrine or phenylephrine

Ephedrine does not appreciably decrease uterine blood flow.

Question 25

The patient will undergo surgery to remove a pheochromocytoma. a. If you were to both alpha-block and beta-block the patient, would you beta-block the patient before you alpha-block, or would alpha-block before you beta-block? b. What alpha-adrenergic blocker could you use to control hypertension during the case?

Answer 25

Block ALPHA receptors first. Alpha-adrenergic receptor blockade causes arterial dilatation, a decrease in systemic vascular resistance, and a decrease in afterload. These changes make it easier for the heart to eject blood after beta-adrenergic receptor blockade. If beta blockade occurred first, heart failure might result because the beta-blocked heart might not be able to eject an adequate stroke volume when systemic vascular resistance and afterload become elevated as a result of increases in circulating epinephrine and norepinephrine. b. Phentolamine (Regitine) is an alpha blocker that could be selected during the case.

Question 26

Your patient has severe asthma. a. What adrenergic agents would you avoid using in this patient?

Answer 26

Avoid drugs that block beta-2 adrenergic receptors such as propranolol or labetalol, and also avoid drugs that stimulate the release of histamine such as trimethaphan (Arfonad), o-tubocurarine, atracurium, and mivacurium

Question 27

Your patient is on a high dose beta-blocker. | a. You would avoid using what intravenous general anesthetic? Why?

Answer 27

Ketamine should be avoided. Ketamine stimulates the sympathetic nervous system, which will constrict blood vessels and increase systemic vascular resistance and afterload. The beta-blocked heart may not tolerate the increased afterload, and heart failure may ensue.

Question 28

The patient is beta-blocked to treat hypertension. The anesthesiologist terminates the beta-blocker therapy 48 hours before surgery. Preoperatively, the patient shows tachycardia, hypertension and ECG signs of myocardial ischemia. a. What explains the tachycardia and ECG signs of myocardial ischemia?

Answer 28

When beta receptors are blocked by a competitive antagonist, beta receptors up-regulate. When the beta blocker is withdrawn, the unblocked heart with excessive numbers of beta receptors is hypersensitive to catecholamines. The result is tachycardia, hypertension, and possibly myocardial ischemia.

Question 29

The patient is beta-blocked to treat hypertension. The anesthesiologist terminates the beta-blocker therapy 48 hours before surgery. Preoperatively, the patient shows tachycardia, hypertension and ECG signs of myocardial ischemia. You probably would treat this problem with what agent?

Answer 29

Esmolol (Brevibloc), because it is short acting and titrating to a desirable blood pressure is fairly easy to accomplish.

Question 30

The patient is beta-blocked to treat hypertension. The anesthesiologist terminates the beta-blocker therapy 48 hours before surgery. Preoperatively, the patient shows tachycardia, hypertension and ECG signs of myocardial ischemia. c. Should beta-blocker therapy be discontinued prior to surgery?

Answer 30

No, beta blocker therapy generally should not be discontinued prior to surgery.

Question 31

1. You want to protect the patient from excess salivation. If you also want to promote sedation, what drug will you use? If you want to avoid sedation, what drug will you use? Of the available antisialagogues, which is least efficacious in reducing salivation?

Answer 31

Scopolamine Glycopyrrolate (robinul) Atropine