Nokea
The tiny space between neurons or a neuron and its target muscle is the:
- A. dendrite
- B. axon
- C. neuron cell body
- D. synapse
Correct Answer: D
Rationale: The synapse is the tiny gap between neurons or between a neuron and its target cell, such as a muscle. It is the site where neurotransmitters are released to transmit signals from one cell to another. When an action potential reaches the axon terminal, neurotransmitters are released into the synapse and bind to receptors on the postsynaptic cell, triggering a response. The synapse is crucial for communication within the nervous system.
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Which of the following pathways is not concerned with posture and movement?
- A. Spinocerebellar
- B. Vestibulospinal
- C. Tractus solitarius
- D. ?
Correct Answer: C
Rationale: The tractus solitarius is involved in taste and visceral sensation, not posture and movement. The spinocerebellar and vestibulospinal tracts are involved in motor coordination and balance.
At a visit to the provider's office, an older adult patient's partner reports that the patient has nausea, diarrhea, and a loss of appetite. He has a history of Alzheimer's disease and is taking donepezil (Aricept). The provider should advise which of the following?
- A. Take the drug with food.
- B. Stop taking the drug right away.
- C. Take a reduced dosage of the drug.
- D. Undergo liver function tests right away.
Correct Answer: A
Rationale: Cholinesterase inhibitors such as donepezil commonly cause nausea, vomiting, anorexia, and other gastrointestinal symptoms. This is due to the increase of acetylcholine in all parts of the body, and its subsequent effect on the gastrointestinal tract and other systems of the body. The provider should explain to the patient and his caregiver that taking the drug with food and at bedtime will help minimize uncomfortable gastrointestinal effects. The provider also should instruct the partner to report vomiting, severe diarrhea, weight loss, or signs of gastrointestinal bleeding, such as dark stools or coffee-ground emesis, especially if the patient is also taking a nonsteroidal anti-inflammatory drug. At this point, it is not necessary to stop taking the drug, reduce the dosage, or undergo liver function tests.
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.
The vagus nerve
- A. Arises from the medulla as a single nerve
- B. Receives nucleus ambiguous fibres from the accessory nerve
- C. Supplies motor fibres to the diaphragm
- D. Supplies sensory fibres to the facial region
Correct Answer: B
Rationale: The vagus nerve receives motor fibers from the nucleus ambiguus, which also contributes to the accessory nerve. It innervates muscles of the pharynx and larynx.
The diameter of a motor nerve fibre is
- A. 1-2 micrometre
- B. 3-5 micrometre
- C. 5-12 micrometre
- D. 12-20 micrometre
Correct Answer: D
Rationale: Motor nerve fibers, such as alpha motor neurons, typically have a diameter of 12-20 micrometers. Larger diameters allow for faster conduction of action potentials.