Question

10. The MRI of a male newborn reveals cerebral hemispheres that have areas of small irregular gyri (microgyri) intermixed with areas containing very large gyri (pachygyri). Which of the following would most likely explain these developmental defects?

a. Failure of the anterior neuropore to close

b. Stenosis of the cerebral aqueduct

c. Agenesis of the corpus callosum

d. Improper migration of neuroblasts on the radial glia

e. Failure of microglia to invade the developing nervous system

12. The neuropathologist examines a tumor removed from the ventricular system of a 36-year-old woman. He observes cells that appear completely normal but they do not sit on a continuous basal lamina. These cells are most likely which of the following?

a. Endothelial cells of the choroid plexus

b. Endothelial cells lining arteries

c. Ependymal cells

d. Endothelial cells lining veins

13. A sample of CSF is taken, by lumbar puncture, from a 27-year-old woman who presents with vague neurologic complaints. Which of the following would most likely represent an abnormal condition in the CSF of this patient?

a. 120mg/dL protein

b. Less than 5 lymphocytes per milliliter

c. Lower K and Ca2 than blood plasma

d. Higher Mg2 and Cl than blood plasma

14. Lumbar puncture of a 59-year-old man yields a sample of CSF containing large amounts of red blood cells. Which of the following is the most likely explanation of these cells in the CSF of this patient?

a. Astrocytoma

b. Multiple sclerosis

c. Bacterial meningitis

d. Rupture of an intracranial aneurysm

e. Meningeal syphilis

Answer 1

10. Correct answer:- (d) d. Improper migration of neuroblasts on the radial glia.
Explanation-Pachygyria is caused by a breakdown in the fetal neuronal migration process due to genetic or possibly environmental influences.
-The affected cerebral cortex will typically have only four developed layers instead of the normal six.

12. Correct answer:- (a) b. Endothelial cells lining arteries.

13. Correct answer:- (a) 120mg/dL protein.
Explanation- normal value of protein is 15–45 mg/dL.

14. Correct answer:- (d) Rupture of an intracranial aneurysm.
Explanation- RBCs will appear whenever bleeding has occurred. Red cells in CSF signal subarachnoid hemorrhage, stroke, or traumatic tap.