CHAPTER 16 - Book Review Questions

Question 1

The following statements concern the ventricular system:

(a) The fourth ventricle has a rectangular-shaped floor.
(b) The pineal body is suspended from the roof of the fourth ventricle.
(c) The nerve centers controlling the heart rate and blood pressure lie beneath the floor of the third ventricle.
(cl) The choroid plexus of the lateral ventricle projects into the cavity on its medial side through the choroidal fissure.
(e) The foramen of Magendie is an aperture in the roof of the third ventricle.

Answer 1

D is correct.

• The choroid plexus of the lateral ventricle projects into the cavity on its medial side through the choroidal fissure (see Fig. 16-7). A. The fourth ventricle has a diamond-shaped floor called the rhomboid fossa (see Fig. 16-11).
  B. The pineal body is not suspended from the roof of the fourth ventricle (see Fig. 16-4). C. The nerve centers controlling the heart rate and blood pressure lie beneath the floor of the fourth ventricle (see Fig. 16-11). E. The foramen of Magendie is an aperture in the roof of the fourth ventricle (see Fig. 16-12).

Question 2

The following statements concern the ventricular system:

(a) The cerebral aqueduct connects the third ventricle with the fourth ventricle.
(b) The two lateral ventricles communicate directly with one another through the foramen of Monro.
(c) The ventricles are developed from the embryonic endoderm.
(cl) It is lined throughout with squamous epithelium.
(e) Choroid plexuses are found only in the lateral ventricles.

Answer 2

A is correct.

• The cerebral aqueduct connects the third ventricle with the fourth ventricle (see Fig. 16-4). B. The two lateral ventricles do not communicate directly with one another through the interventricular foramen (foramen of Monro) (see Fig. 16-2). C. The ventricles are developed from the neural tube in the embryo. D. The ventricular system is lined throughout with ependyma, which is a single layer of cuboidal or columnar cells. E. The choroid plexuses are found in the lateral ventricles and the third and the fourth ventricles.

Question 3

The following statements concern the blood-brain barrier (BBB):

(a) It protects the brain from toxic compounds of low molecular weight.
(b) It is present in the pineal gland.
(c) The endothelial cells of the blood capillaries are nonfenestrated.
(d) The endothelial cells of the blood capillaries are held together by localized tight junctions.
(e) L-Dopa has difficulty passing through it in the treatment of Parkinson disease.

Answer 3

C is correct.

• The endothelial cells of the blood capillaries in the BBB are nonfenestrated. A. The BBB protects the brain from toxic compounds of high molecular weight. B. The BBB is not present in the pineal gland. D. The endothelial cells of the blood capillaries of the BBB are not held together by localized tight junctions; they pass around the endothelial cells. E. L-Dopa readily passes through the BBB in the treatment of Parkinson disease.

Question 4

The following statements concern the blood-brain barrier (BBB):

(a) Chloramphenicol and the tetracyclines cannot cross the barrier.
(b) In the newborn child, the BBB is not fully developed.
(c) Cerebral trauma or inflammation has little effect on BBB integrity.
(d) Gases and water pass with difficulty through the barrier.
(e) Glucose and electrolytes pass quickly through the barrier.

Answer 4

B is correct.

• In the newborn child, the BBB is not fully developed. A. Chloramphenicol and the tetracyclines can cross the BBB. C. Cerebral trauma and inflammation may have a great effect on the integrity of the BBB. D. Gases and water pass readily through the BBB. E. Glucose and electrolytes pass slowly through the BBB.

Question 5

The following statements concern the blood-cerebrospinal fluid barrier:

(a) The beltlike tight junctions between the choroidal ependymal cells form the barrier.
(b) The proteins and most hexoses, other than glucose, are able to cross the barrier.
(c) Gases and water cannot pass through the barrier.
(d) Lipid-soluble substances have difficulty passing through the barrier.
(e) The basement membrane of the endothelial cells plays a vital part in the formation of the barrier.

Answer 5

A is correct.

• In the blood-cerebrospinal fluid barrier, the beltlike tight junctions between the choroidal ependymal cells form the barrier. B. The proteins and most hexoses, other than glucose, are unable to cross the blood-cerebrospinal fluid barrier. C. Gases and water pass readily through the barrier. D. Lipid-soluble substances have no difficulty passing through the barrier. E. The basement membrane of the endothelial cells plays no part in the formation of the barrier.

Question 6

The following structures are associated with the roof of the fourth ventricle:

(a) Tectum of the midbrain
(b) Choroid plexus
(c) Pineal gland
(d) Corpus callosum
(e) Temporal lobes of the cerebral hemispheres

Answer 6

B is correct.

• The choroid plexus is present in the roof of the fourth ventricle (see Fig. 16-8).

Question 7

The following statements concern the cerebrospinal fluid (CSF) in the fourth ventricle:

(a) It is produced mainly by the choroid plexus of the cerebral aqueduct.
(b) It leaves the midbrain through the interventricular foramina.
(c) It enters the spinal cord through the foramen of Luschka.
(d) It is dark yellow in color.
(e) It escapes into the subarachnoid space through the apertures in the roof of the fourth ventricle.

Answer 7

E is correct.

• The CSF in the fourth ventricle escapes into the subarachnoid space through apertures in the roof of the ventricle (see Fig. 16-13). A. The CSF in the fourth ventricle is produced mainly in the choroid plexuses of the lateral, third, and fourth ventricles. B. It leaves the midbrain through the cerebral aqueduct (Fig. 16-17). C. The CSF in the fourth ventricle enters the spinal cord through the central canal (see Fig. 16-7). D. The CSF is clear and colorless.

Question 8

The lateral boundaries of the fourth ventricle are formed by:

(a) the tentorium cerebelli.
(b) the sulcus limitans.
(c) the cerebellar peduncles.
(d) the cerebral peduncles.
(e) the striae medullares.

Answer 8

C is correct.

• The lateral boundaries of the fourth ventricle are formed by the cerebellar peduncles (see Fig. 16-10).

Question 9

The following important nuclei lie beneath the floor of the fourth ventricle:

(a) Oculomotor nucleus
(b) Trochlear nucleus
(c) Trigeminal nucleus
(d) Hypoglossal nucleus
(e) Olfactory nucleus

Answer 9

D is correct.

• The hypoglossal nucleus lies beneath the floor of the fourth ventricle (see hypoglossal triangle in Fig. 16-11).

Question 10

The following statements concern the third ventricle:

(a) It is situated between the two thalami.
(b) It communicates with the lateral ventricles through the cerebral aqueduct.
(c) It is continuous with the fourth ventricle through the interventrlcular foramen.
(d) The choroid plexus is located on the floor.
(e) The choroid plexus receives its arterial supply through the posterior cerebral arteries.

Answer 10

A is correct.

• The third ventricle lies between the thalami (see Fig. 16-5). B. The third ventricle communicates with the lateral ventricles through the interventricular foramina (see Fig. 16-2). C. The third ventricle is continuous with the fourth ventricle through the cerebral aqueduct (see Fig. 16-3). D. The choroid plexus of the third ventricle is situated in the roof (see Fig. 16-6). E. The choroid plexus of the third ventricle receives its arterial supply from the internal carotid and basilar arteries.

Question 11

The following statements concern the subarachnoid space:

(a) lt contains cerebrospinal fluid (CSF) and the cerebral arteries but not the cerebral veins.
(b) lt does not communicate with the cisterns.
(c) The fourth ventricle drains into it through a
single foramen.
(d) The space does not surround the cranial and
spinal nerves where they leave the skull and the
vertebral canal.
(e) It is the interval between the arachnoid mater
and the pia mater.

Answer 11

E is correct.

• The subarachnoid space is the interval between the arachnoid mater and the pia mater (see Fig. 16-1). A. The subarachnoid space contains CSF, the cerebral arteries, and the cerebral veins. B. The subarachnoid space is in free communication with the cisterns. C. The fourth ventricle drains into the subarachnoid space through three openings in its roof (see Fig. 16-1). D. The subarachnoid space surrounds the cranial and spinal nerves to the
  point where they leave the skull and the vertebral
  canal.

Question 12

The following statements concern cerebrospinal
fluid (CSF) formation:

(a) None of the fluid originates from the brain substance.
(b) lt is largely formed by the choroid plexuses.
(c) It is passively secreted by the ependymal cells
covering the choroid plexuses.
(d) It is produced continuously at a rate of about
5 ml/min.
(e) It is drained into the subarachnoid space from
the lymphatic vessels of the brain and spinal
cord.

Answer 12

B is correct.

• The CSF is largely formed by the choroid plexuses. A. Some of the fluid originates from the brain substance. C. The CSF is actively secreted by the ependymal cells covering the choroid plexuses. D. The CSF is produced continuously at a rate of 0.5 mL/min. E. The brain and spinal cord have no lymphatic vessels.

Question 13

The following statements concern the cerebrospinal fluid (CSF):

(a) Its circulation through the ventricles is not
aided by the pulsations of the choroid plexuses.
(b) It extends inferiorly in the subarachnoid space
to the level of the fifth sacral vertebra.
(c) The CSF pressure in the subarachnoid space rises if the Internal jugular veins in the neck are
compressed.
(d) It exits from the ventricular system through the
ventricular foramina.
(e) Its circulation in the subarachnoid space is
aided by the pulsations of the cerebral and
spinal veins.

Answer 13

C is correct.

• The CSF pressure in the subarachnoid space rises if the internal jugular veins in the neck are compressed. A. The circulation of the CSF through the ventricles is aided by the pulsations of the arteries in the choroid plexuses. B. The CSF extends inferiorly in the subarachnoid space in the vertebral column to the level of the lower border of the second sacral vertebra (see Fig. 16-1). D. The CSF exits from the ventricular system of the brain through the foramina of Luschka and Magendie (see Fig. 16-1). E. The circulation of the CSF in the subarachnoid space is aided by the pulsations of the cerebral and spinal arteries.

Question 14

The following statements concern cerebrospinal
fluid (CSF) absorption:

(a) The fluid is passed into the blood by active
transport through the cells forming the arachnoid villi.
(b) The major sites for its absorption are into the
veins in the subarachnoid space and the perineural lymph vessels.
(c) Arachnoid villi play an important role in its
absorption.
(d) Fine tubules found within the arachnoid villi
play a minor role in CSF flow into the venous
sinuses.
(e) In communicating hydrocephalus, flow is
obstructed within the ventricular system and to the outflow from the ventricular system to the subarachnoid space.

Answer 14

C is correct.

• The arachnoid villi play an important role in the absorption of CSF into the cranial venous sinuses. A. The CSF does not pass into the blood by active transport through the cells forming the arachnoid villi. B. The veins in the subarachnoid space and the perineural lymph vessels are minor sites for the absorption of CSF. D. The fine tubules found within the arachnoid villi play a major role in the flow of the CSF into the venous sinuses. E. In communicating hydrocephalus, flow of the CSF is not obstructed within the ventricular system or to the outflow from the ventricular system to the subarachnoid space.

Question 15

A 24-year-old woman complaining of recent onset of severe headaches and several attacks of morning vomiting was seen by a neurologist. A thorough physical examination revealed findings suggesting that she might have an intracranial tumor involving the cerebellum. The physician ordered an MRI of the patient’s brain with particular reference to the contents of the posterior cranial fossa.

• check book for the figure

Figure 16-25 is a coronal MRI (contrast enhanced) through the fourth ventricle. The radiologist made the following correct observations in his report except:

(a) The bones of the skull showed nothing abnormal. The cerebral cortex appeared to be normal.
(b) The midline structures were not deflected to one or the other side.
(c) The cavity of the fourth ventricle was distorted and larger than normal.
(d) The body of the lateral ventricle had a normal appearance.

Answer 15

C is correct.

• The size and the shape of the cavity of the fourth ventricle were within normal limits.

Question 16

A 21-year-old pregnant woman was invited to a reunion party and during the course of the evening, she drank several gin and tonics. The party was followed by several others extending over a 3-week period during which she drank heavily. Six months later, she gave birth to a boy who was diagnosed as having congenital hydrocephalus.

The pediatric neurologist carefully questioned the mother and came to the following correct conclusions except:

(a) The consumption of a large amount of alcohol during pregnancy usually has no adverse
effects on the developing fetus.
(b) The high alcoholic intake coincided with the
first trimester.
(c) The alcohol had crossed the placental barrier and entered the fetal circulation.
(d) The alcohol had probably also crossed the fetal blood-brain barrier (BBB) and entered the brain.
(e) The neurologist was of the opinion that the toxic effect of alcohol was probably responsible for the hydrocephalus.

Answer 16

A is correct.

• Many chemical substances when consumed are toxic to the central nervous system (CNS), and alcohol in large quantities is one of the worst offenders. During the first trimester, alcohol can readily access the brain at a time when it is particularly vulnerable. Before a physician prescribes a therapeutic drug, he or she must know whether the drug will cross the BBB and what effect, if any, that drug will have on the CNS.