Nokea
Which of the following statements about axon-guidance is TRUE?
- A. Netrins are long-range cues for chemorepulsion
- B. Semaphorins are short-range cues for chemorepulsion
- C. Cadherins are short-range cues for contact attraction
- D. Ephrins are short-range cues for contact attraction
Correct Answer: C
Rationale: Cadherins are cell adhesion molecules that mediate short-range contact attraction, guiding axons to their targets. Netrins, semaphorins, and ephrins also play roles in axon guidance, but they function through different mechanisms, such as long-range chemotaxis or repulsion. This diversity of guidance cues ensures precise navigation of growing axons.
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Which treatment modality should a nurse recommend to help a patient diagnosed with somatic symptom disorder cope more effectively?
- A. Flooding
- B. Relaxation
- C. Response prevention
- D. Systematic desensitization
Correct Answer: B
Rationale: The correct answer is B: Relaxation. For a patient with somatic symptom disorder, relaxation techniques can help reduce anxiety and physical symptoms associated with the disorder. Relaxation promotes a sense of calm, reduces stress, and can improve coping skills. Flooding (A) involves exposing a patient to a feared stimulus in a sudden and intense manner, which can exacerbate symptoms in somatic symptom disorder. Response prevention (C) is used in treating obsessive-compulsive disorder, not somatic symptom disorder. Systematic desensitization (D) is a technique used for phobias, not somatic symptom disorder.
Which type of fiber could be considered the longest?
- A. preganglionic parasympathetic
- B. preganglionic sympathetic
- C. postganglionic parasympathetic
- D. postganglionic sympathetic
Correct Answer: A
Rationale: The correct answer is A: preganglionic parasympathetic. Preganglionic fibers are the longest in the autonomic nervous system, with parasympathetic fibers generally having longer preganglionic fibers compared to sympathetic fibers. Parasympathetic preganglionic fibers originate from the cranial nerves and sacral spinal cord, allowing them to travel longer distances to reach their ganglia. In contrast, sympathetic preganglionic fibers originate from the thoracic and lumbar spinal cord, resulting in shorter lengths compared to parasympathetic fibers. Therefore, preganglionic parasympathetic fibers are considered the longest among the given choices. Postganglionic fibers, whether parasympathetic or sympathetic, are shorter as they only need to travel to their target organs from the ganglia.
Summary:
- A: Correct, as preganglionic parasympathetic fibers are the longest in the autonomic nervous system
Which structure is encircled by the circle of Willis?
- A. cavernous sinus
- B. pineal gland
- C. aqueduct of the midbrain
- D. pituitary stalk
Correct Answer: D
Rationale: The circle of Willis encircles the pituitary stalk and provides collateral blood flow to the brain. It is a critical anastomotic structure at the base of the brain.
Which of the following are the parts of neurons?
- A. brain, spinal cord, and vertebral column
- B. dendrite, axon, and cell body
- C. sensory and motor
- D. cortex, medulla and sheath
Correct Answer: B
Rationale: Neurons are the basic building blocks of the nervous system and consist of three main parts: dendrites, axons, and the cell body. Dendrites receive signals from other neurons, the cell body contains the nucleus and organelles, and the axon transmits signals to other neurons or target cells. These components work together to facilitate communication within the nervous system, enabling sensory perception, motor control, and cognitive functions.
A patient reports nearly having a motor vehicle crash and states that his heart was pounding and he was breathing heavy and fast. Currently, the patient's heart rate and breathing are within normal limits. Which neurotransmitter has resumed control after the patient's incident?
- A. Serotonin
- B. Prostaglandin
- C. Acetylcholine
- D. Norepinephrine
Correct Answer: C
Rationale: Acetylcholine is the neurotransmitter responsible for mediating parasympathetic (rest-and-digest) functions, which resume control after a sympathetic (fight-or-flight) response. Norepinephrine mediates the sympathetic response, while serotonin and prostaglandins are involved in mood and pain regulation. Understanding neurotransmitter roles is key to explaining autonomic nervous system function.