Nokea
What is the role of semaphorins and Eph ligands in development of the nervous system?
- A. The semaphorins and Eph ligands are growth factors that stimulate cell division of neurons.
- B. The semaphorins and Eph ligands act as signals for the outgrowth of neuronal growth cones; in general, both lead growth cones to turn away.
- C. The semaphorins and Eph ligands act as signals for the outgrowth of neuronal growth cones; in general, both lead growth cones to come toward them.
- D. The semaphorins and Eph ligands are cell-cell adhesion molecules that bind adjacent neurons together.
Correct Answer: B
Rationale: Semaphorins and Eph ligands act as guidance cues for growing axons. They generally function as repulsive signals, causing growth cones to turn away from inappropriate regions. This ensures precise navigation of axons to their correct targets, which is essential for establishing functional neural circuits.
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A patient is discharged from the outpatient clinic following application of a synthetic fiberglass long arm cast for a fractured ulna. Before discharge, the nurse instructs the patient to do what?
- A. Never get the cast wet.
- B. Move the shoulder and fingers frequently.
- C. Place tape petals around the edges of the cast when it is dry.
- D. Use a sling to support the arm at waist level for the first 48 hours.
Correct Answer: B
Rationale: Moving the unaffected parts promotes circulation and reduces stiffness.
Dilatation of the peripheral arterial blood vessels can be caused by:
- A. thromboxane A2
- B. adenosine diphosphate
- C. endothelin
- D. prostaglandins
Correct Answer: D
Rationale: Prostaglandins, particularly prostacyclin (PGI2), are potent vasodilators. Thromboxane A2, adenosine diphosphate, and endothelin are vasoconstrictors and do not cause peripheral arterial dilatation.
The posterior column transmits which of the following
- A. Afferent pain and temperature
- B. Afferent tendon stretch impulses
- C. Motor tracts
- D. ?
Correct Answer: B
Rationale: The posterior columns (fasciculus gracilis and cuneatus) transmit proprioceptive and fine touch sensations. These pathways are essential for coordination and balance.
What is the best description of the periosteum?
- A. Lining of a joint capsule
- B. A characteristic of skeletal muscle
- C. Most common type of cartilage tissue
- D. Fibrous connective tissue covering bone
Correct Answer: D
Rationale: The periosteum is fibrous connective tissue covering bone.
Which of the following is a sign of urinary retention in older adults with neurologic deficit?
- A. Amnesia
- B. Hypotension
- C. Hypertension
- D. A behavior change
Correct Answer: D
Rationale: Behavior changes, such as confusion, can indicate urinary retention.