Question 1

Small ligaments that connect the pia to the arachnoid and dura mater are called

Accepted Answer

Denticulate ligaments are extensions of the pia mater that anchor the spinal cord to the dura mater, providing stability within the vertebral column. They are not found in the peritoneum, eye, knee, or associated with collateral structures.

Question 2

An anthropologist observes several small pits along the groove for the superior sagittal sinus in a human calvaria. What structure most likely contributed to the formation of these pits?

Accepted Answer

Arachnoid granulations are responsible for the formation of small pits along the groove for the superior sagittal sinus in the human calvaria, as they are involved in the reabsorption of cerebrospinal fluid into the venous system.

Question 3

During the lumbar puncture it was noted that the intracranial pressure of the woman was normal. Which of the following most precisely indicates normal intracranial pressure in an adult?

Accepted Answer

Normal intracranial pressure in an adult is generally considered to be less than 15 mm Hg. Values above this threshold may indicate increased intracranial pressure, which can be a sign of various medical conditions.

Question 4

What is the total volume of CSF produced by a normal adult in one day?

Accepted Answer

The total volume of cerebrospinal fluid (CSF) produced by a normal adult in one day is approximately 480-500 ml.

Question 5

The head CT of a 74-year-old man indicates a hypodense crescent-shaped accumulation of fluid over the left hemisphere. This patient is most likely suffering from which of the following?

Accepted Answer

The description of a hypodense crescent-shaped accumulation of fluid over one hemisphere on a head CT is characteristic of a subdural hematoma. This condition occurs when blood collects between the dura mater and the arachnoid mater, often due to venous bleeding, and is more common in older individuals due to brain atrophy and increased venous fragility.

Question 6

The collection of modified ependymal cells that produce CSF within the ventricular system of the brain is referred to as the

Accepted Answer

The choroid plexus is a collection of modified ependymal cells located in the ventricles of the brain, responsible for the production of cerebrospinal fluid (CSF).

Question 7

After returning from a wildlife tour of Africa, a 22-year-old man experiences headaches, fever, stiff neck, and lethargy. Lumbar puncture reveals increased white blood cell count and reduced glucose levels. This patient is likely suffering from which of the following?

Accepted Answer

The symptoms of headaches, fever, stiff neck, and lethargy, along with the lumbar puncture findings of increased white blood cell count and reduced glucose levels, are indicative of bacterial meningitis.

Question 8

A 65-year-old woman complains to her family physician of increasing weakness in her lower limbs. A magnetic resonance image indicates a calcified mass along the falx cerebri. What is the most likely diagnosis of this mass?

Accepted Answer

Meningiomas are the most common primary brain tumors that originate from the meninges, the membranes surrounding the brain and spinal cord. They are often found along the falx cerebri and can present with symptoms due to compression of adjacent brain structures. Their appearance as calcified masses on imaging is characteristic, distinguishing them from the other options listed.

Question 9

A developmental biologist is interested in the developmental patterning of the leptomeninges. Which of the following structures are referred to as the leptomeninges?

Accepted Answer

The leptomeninges refer to the two innermost layers of the meninges that cover the brain and spinal cord, which are the pia mater and the arachnoid mater.

Question 10

Which of the following would most likely account for the hypodense appearance of the fluid?

Accepted Answer

Chronic vascular bleeding is more likely to account for the hypodense appearance of the fluid on imaging studies because over time, the blood products break down and become less dense than acute blood. This process results in a hypodense (darker) appearance on CT scans, distinguishing it from the hyperdense (brighter) appearance of acute hemorrhage.

Question 11

During a head and neck dissection, a group of medical students remove the cerebrum, inadvertently leaving behind the cerebellum. Which of the following structures caused the cerebellar hemispheres to become separated from the brain?

Accepted Answer

The tentorium cerebelli is a structure that separates the cerebellum from the inferior portion of the cerebrum, making it responsible for the separation of the cerebellar hemispheres from the brain when the cerebrum is removed.

Question 12

Large quantities of CSF collect in cisterns present throughout the central nervous system. These cisterns are formed in which of the following structures?

Accepted Answer

The cisterns where large quantities of cerebrospinal fluid (CSF) collect are formed in the subarachnoid space. This space lies between the arachnoid mater and the pia mater, two of the three meningeal layers that cover the brain and spinal cord.

Question 13

After returning from her trip to Taiwan, a 28-year-old woman complains to her family physician of a headache, neck pain, and a fever. The physician orders a lumbar puncture. Which of the following most accurately indicates the normal white blood cell count in adult CSF?

Accepted Answer

The normal white blood cell count in adult cerebrospinal fluid (CSF) is <5 cells per mm^3. Option E, <10 per mm^3, is the closest to this normal range, indicating minimal to no white blood cell presence, which is expected in healthy individuals.

Question 14

A 47-year-old woman complains to her family physician of recurrent headaches that have worsened over the past 6 months. A magnetic resonance image reveals a mass within the middle cranial fossa. Which cranial nerves innervate the dura in this region?

Accepted Answer

The trigeminal nerve (Cranial Nerve V) is responsible for innervating the dura mater in the middle cranial fossa, playing a key role in the sensation, including pain, from this area.

Question 15

In order to determine if a new drug will cross the blood-brain barrier, a research scientist tags it with a dye and then injects it into the vascular system of a rat. Examination of the sectioned brain indicates that the dye was not detected in the brain tissue. What is the most likely explanation of this observation?

Accepted Answer

Tight junctions between capillary endothelial cells in the blood-brain barrier prevent many substances, including certain dyes and drugs, from passing from the bloodstream into the brain tissue.

Question 16

A 5-year-old boy is diagnosed with a choroid plexus papilloma. Based on this diagnosis, what condition is this patient likely to have?

Accepted Answer

Choroid plexus papillomas are tumors that can block the flow of cerebrospinal fluid in the brain, potentially leading to hydrocephalus, a condition characterized by an accumulation of fluid in the brain's cavities.

Question 17

Which part of the ventricular system is located adjacent to the thalamus and hypothalamus?

Accepted Answer

The third ventricle is located adjacent to the thalamus and hypothalamus, forming part of the central cavity of the brain where cerebrospinal fluid circulates.

Question 18

Which of the following is the most common cause of this illness in adults?

Accepted Answer

Streptococcus pneumoniae is the most common cause of pneumonia in adults, leading to bacterial pneumonia.

Quiz 13: The Chemical Senses of Taste and Smell