The following muscles are supplied by posterior rami of spinal nerves EXCEPT
- A. Erector spinae
- B. Levator costae
- C. Splenius
- D. Scalene posterior
Correct Answer: D
Rationale: The scalene muscles are innervated by the anterior rami of cervical spinal nerves, not the posterior rami. The posterior rami supply intrinsic back muscles like the erector spinae.
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When assessing a patient's level of consciousness, which response would indicate a decreased level of consciousness?
- A. The patient is drowsy but can be easily aroused.
- B. The patient is alert and oriented.
- C. The patient responds quickly to verbal stimuli.
- D. The patient is fully awake and responsive.
Correct Answer: A
Rationale: A drowsy patient who can be easily aroused indicates a decreased level of consciousness. Alertness, quick responses, and full wakefulness are normal findings.
The Schwann cells form a myelin sheath around the:
- A. dendrites
- B. cell body
- C. nucleus
- D. axon
Correct Answer: D
Rationale: Schwann cells are responsible for forming the myelin sheath around axons in the peripheral nervous system (PNS). Dendrites, cell bodies, nuclei, and nodes of Ranvier are not directly myelinated by Schwann cells. Therefore, D is the correct answer.
The nurse is explaining the neurological system to a group of nursing students. How many pairs of spinal nerves should the nurse explain are contained within the human body?
- A. 15
- B. 25
- C. 31
- D. 42
Correct Answer: C
Rationale: There are 31 pairs of spinal nerves in the human body: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Understanding the anatomy of the spinal nerves is essential for explaining neurological function.
Which of these statements about the peripheral nervous system is correct?
- A. The CNs enter the brain through the spinal cord.
- B. Efferent fibers carry sensory input to the central nervous system through the spinal cord.
- C. The peripheral nerves are inside the central nervous system and carry impulses through their motor fibers.
- D. The peripheral nerves carry input to the central nervous system by afferent fibers and away from the central nervous system by efferent fibers.
Correct Answer: D
Rationale: The correct answer is D because the peripheral nerves carry sensory input to the central nervous system by afferent fibers and motor commands away from the central nervous system by efferent fibers. This is known as the afferent-efferent division of the peripheral nervous system. Choice A is incorrect because cranial nerves (CNs) enter the brain directly, not through the spinal cord. Choice B is incorrect because efferent fibers carry motor commands away from the central nervous system, not sensory input. Choice C is incorrect because peripheral nerves are outside the central nervous system and do not carry impulses through motor fibers; instead, they carry motor commands through efferent fibers.
What neurotransmitter will result in constriction of the pupil?
- A. norepinephrine
- B. acetylcholine
- C. epinephrine
- D. serotonin
Correct Answer: B
Rationale: The correct answer is B: acetylcholine. Acetylcholine is the neurotransmitter responsible for causing constriction of the pupil. When acetylcholine binds to muscarinic receptors in the eye muscles, it triggers the muscles to contract, leading to pupil constriction. Norepinephrine (choice A) and epinephrine (choice C) are both involved in the fight-or-flight response and dilate the pupils. Serotonin (choice D) does not directly affect pupil constriction.