Nokea
Deuterium oxide and inulin are injected into a normal 30-year-old man. The volume of distribution of deuterium oxide is found to be 42 L and that of inulin 14 L.
- A. The man's intracellular fluid volume is about 14 L.
- B. The man's intracellular fluid volume is about 28 L.
- C. The man's plasma volume is about 7 L.
- D. The man's interstitial fluid volume is about 9 L.
Correct Answer: B
Rationale: Deuterium oxide distributes throughout total body water (TBW), while inulin distributes only in extracellular fluid (ECF). The intracellular fluid (ICF) volume is calculated as TBW - ECF. Here, TBW = 42 L and ECF = 14 L, so ICF = 42 - 14 = 28 L. This calculation is based on the principle that deuterium oxide measures all body water, while inulin is restricted to the extracellular compartment.
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The tectum is located in the _____________.
- A. hindbrain
- B. midbrain
- C. forebrain
- D. spinal cord
Correct Answer: B
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The cervical sympathetic trunk
- A. Descends from the upper posterior triangle to the first rib
- B. Runs lateral to the vertebral artery
- C. Lies behind the carotid sheath
- D. Lies behind the prevertebral fascia
Correct Answer: B
Rationale: The cervical sympathetic trunk runs lateral to the vertebral artery and posterior to the carotid sheath. It contains ganglia that provide sympathetic innervation to the head and neck.
Which of the following statements is true of dementia?
- A. It is a progressive neurological disease that affects the motor neurons of the nervous system.
- B. It is the general term for conditions that involve loss of memory and impaired cognition.
- C. It is an autoimmune neuromuscular disease that affects the skeletal muscles.
- D. It is the general term used to describe a cluster of symptoms including bradykinesia with rigidity or tremor.
Correct Answer: B
Rationale: Dementia is an umbrella term for a group of conditions characterized by a decline in cognitive function, including memory loss, impaired reasoning, and changes in behavior. Alzheimer's disease is the most common form of dementia, but other types include vascular dementia and Lewy body dementia.
Which is the most common neurotransmitter in the brain?
- A. serotonin
- B. glutamate
- C. dopamine
- D. GABA
Correct Answer: B
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Do neurons make synapses with other neurons?
- A. No, the only role of neurons is to cause muscles to contract
- B. No, neurons can enervate tissues other than muscle, but there is no need for them to enervate other neurons
- C. Yes, neurons make contacts with other neurons that are identical to those they make with muscle cells
- D. Yes, however, the connections neurons make with each other differ from those they make with muscle cells in that cell-cell adhesion molecules link the pre-synaptic and post-synaptic membranes together
Correct Answer: D
Rationale: Neurons form synapses with other neurons to create complex neural circuits. These synapses differ from neuromuscular junctions in their structure and function, often involving specialized cell-cell adhesion molecules and signaling mechanisms that enable precise communication between neurons.