Chapter 18: Skeletal Muscle Relaxants (Neuromuscular Blocking Agents)

Chapter 18: Skeletal Muscle Relaxants (Neuromuscular Blocking Agents)

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. Primary clinical uses of neuromuscular blocking agents include which of the following?
2. Facilitate endotracheal intubation
3. Relieve anxiety
4. enhance patient-ventilator synchrony
5. Relax muscle during surgery
6. Reduce intracranial pressure in intubated patients

 

a.	1 and 2 only
b.	1, 2, and 3 only
c.	1, 3, 4, and 5 only
d.	1, 2, 3, 4, and 5

 

 

ANS:  C

The clinical uses of neuromuscular blocking agents are as follows:

• To facilitate endotracheal intubation
• To provide muscle relaxation during surgery, particularly of the thorax and abdomen
• To enhance patient-ventilator synchrony
• To reduce intracranial pressure in intubated patients with uncontrolled intracranial pressure
• To reduce oxygen consumption
• To terminate convulsive status epilepticus and tetanus in patients refractory to other therapies
• To facilitate procedures or diagnostic studies
• To maintain immobility in selected patients (e.g., trauma patients)

 

REF:   p. 306

 

2. The neurotransmitter released by all somatic motor nerves is

a.	epinephrine.
b.	acetylcholine.
c.	norepinephrine.
d.	acetylcholinesterase.

 

 

ANS:  B

The transmission of nerve conduction in skeletal muscle is chemically mediated by the neurotransmitter acetylcholine (ACh). When a nerve impulse reaches the end of the motor neuron, ACh is released from the presynaptic nerve ending into the synaptic cleft. ACh diffuses across the synaptic space and interacts with specific ACh receptors on the postsynaptic muscle fiber membrane, resulting in a response by the muscle fiber.

 

REF:   p. 306

 

3. The termination of the nerve axon on the skeletal muscle fiber is called the

a.	neuromuscular junction.
b.	adrenergic receptor.
c.	skeletal-muscular junction.
d.	cholinergic receptor.

 

 

ANS:  A

The area between the nerve and muscle, or synapse, is specialized into a motor end plate. This area between the axon and the skeletal muscle fiber is also termed the neuromuscular junction.

 

REF:   p. 306

 

4. Immediately after acetylcholine is released at the neuromuscular junction, it is inactivated by

a.	pseudocholinesterase.
b.	acetaminophen.
c.	adenyl cyclase.
d.	acetylcholinesterase.

 

 

ANS:  D

During the short period that acetylcholine (ACh) is in contact with the muscle fiber membrane, a nerve action potential, or nerve impulse, is initiated in the postsynaptic cell. ACh is broken down and inactivated by the enzyme acetylcholinesterase (AChE) allowing the muscle fiber to repolarize.

 

REF:   p. 306 | p. 307

 

5. Of the following, the only depolarizing agent is

a.	cisatracurium.
b.	pancuronium.
c.	succinylcholine.
d.	vecuronium.

 

 

ANS:  C

Succinylcholine is the only available depolarizing skeletal muscle relaxant. The other choices listed are nondepolarizing agents.

 

REF:   p. 310