Chapter 2: Structural and Functional Organization of the Central Nervous System
A 72-year-old man is brought to the emergency room with left-sided weakness and impaired touch sensation on the left side of the body. Which of the following statements best describes the location of the brain damage producing these neurological signs?
A. Stroke in the left cerebral cortex
B. Stoke in the right cerebral cortex
C. Stoke affecting the right side of the spinal cord
D. Damage to peripheral nerves on the left side of the body
Comment: Because most pathways decussate in the brain; left body, right brain. Peripheral nerve damage on the left side could produce somatic sensory and motor disturbances, but it is unlikely that this damage would be so extensive, to affect the entire left side. If he had a systemic disease that affected nerve function, it would be likely that there would be some bilateral impairment or not symmetrical sensory and motor involvement.
A person was in a car accident and injured the lateral white matter of the spinal cord and became partly paralyzed. Which of the following choices best explains why the person became paralyzed as a consequence of the injury?
A. The injury produced extensive damage to neuronal cell bodies within the white matter.
B. The injury produced extensive damage to astrocytes in the white matter.
C. The injury destroyed the component of the ventricular system that is located in the spinal cord.
D. The injury extensively damaged axons within the white matter.
Comment: Whereas the injury could have damaged astrocytes and the central canal of the ventricular system, this would not necessarily produce paralysis. The injury would certainly have extensively damaged axons within the lateral white matter. This would cause a loss of connections between the brain and the spinal cord.
A patient has Alzheimer disease, which, among other impairments, is associated with a loss of acetylcholine in the forebrain. Which of the following is a major forebrain source of acetylcholine?
B. Ventral tegmental area
Which of the following is a major source of noradrenaline?