Chapter 28  Neuromuscular Junction Blocking Agents

Chapter 28  Neuromuscular Junction Blocking Agents

Complete Chapter Questions And Answers
 

Sample Questions

1. According to the sliding filament theory, what is the initial action in a muscle contraction?

A) Troponin is freed and prevents actin and myosin from reacting with each other.

B) Calcium binds to troponin, which causes the release of actin and myosin binding sites.

C) Actin and myosin molecules react with each other sliding along the filament and making it shorter.

D) Muscle filament relaxes or slides back to the resting position.

Ans: C

Feedback:

Actin and myosin molecules react with each other again and again, sliding along the filament and
making it shorter. This is a contraction of the muscle fiber according to the sliding filament theory. As
the calcium is removed from the cell during repolarization of the muscle membrane, the troponin is
freed and once again prevents the actin and myosin from reacting with each other. The muscle filament
then relaxes or slides back to the resting position. Muscle tone results from a dynamic balance between
excitatory and inhibitory impulses to the muscle.

2. When causing depolarization of the muscle membranes, what neurotransmitter interacts with the
nicotinic cholinergic receptors leading to the release of calcium ions?

A) Acetylcholine

B) Serotonin

C) D-gluconamidoethyl methacrylate (GAMA)

D) Epinephrine

Ans: A

Feedback:

At the acetylcholine receptor site on the effector’s side of the synapse, the acetylcholine interacts with
the nicotinic cholinergic receptors causing the depolarization. Serotonin, GAMA, and epinephrine are
not part of muscle contraction and relaxation.

3. The nurse, working in the preoperative holding area, is caring for a 70-year-old patient who is
scheduled to receive succinylcholine as part of general anesthesia. When collecting the nursing history,

Test Bank – Focus on Nursing Pharmacology (7th Edition by Amy Karch) 454

what condition would require the nurse to notify the anesthesiologist of the need for caution?

A) Bone fracture

B) Malnutrition

C) Fluid volume overload

D) Narrow-angle glaucoma

E) Pregnancy

Ans: A, B, D

Feedback:

Succinylcholine should be used with caution in patients with fractures because the muscle contractions
it causes might lead to additional trauma; in patients with narrow-angle glaucoma or penetrating eye
injuries because intraocular pressure increases. Extreme caution is necessary in the presence of genetic
or disease-related conditions causing low plasma cholinesterase levels (e.g., cirrhosis, metabolic
disorders, carcinoma, burns, dehydration, malnutrition, hyperpyrexia, thyroid toxicosis, collagen
diseases, exposure to neurotoxic insecticides).

4. The nurse is caring for a patient who received succinylcholine during surgery. The nurse would expect
the patient to spend more time in the postanesthesia care unit due to prolonged paralysis and inability to
breathe if the patient was from what ethnic group?

A) American Japanese

B) Alaskan Eskimos

C) Native Americans

D) Hawaiian natives

Ans: B

Feedback:

Alaskan Eskimos belong to a genetic group that is predisposed to low plasma cholinesterase levels,
making them susceptible to prolonged paralysis after succinylcholine use. The other ethnic groups do
not have this genetic predisposition.

5. A patient scheduled for surgery is to have a nondepolarizing neuromuscular junction (NMJ) blocker as
adjunctive anesthesia. The nurse will have cause for concern about prolonged paralysis if the patient
has been taking what medication?

A) An aminoglycoside

B) Aminophylline

C) A barbiturate anesthetic

D) A cephalosporin

Ans: A

Feedback:

Combining nondepolarizing NMJ blockers with aminoglycosides can result in prolonged paralysis, and
this combination should be avoided. This interaction does not occur with barbiturate anesthetics,
cephalosporins, or aminophylline.