Question 1

Lacunar infarctions:

Accepted Answer

Obstructions of blood flow in small,deep arteries result in lacunar infarctions.Lacunae are small cavities that remain after the necrotic tissue is cleared away.These infarctions occur most often in the basal ganglia,internal capsule,thalamus,and brainstem.Signs of lacunar infarctions develop slowly and are often either purely motor or purely sensory,with good recovery being common.

Question 2

Which of the following correctly describes the circulation of CSF?

Accepted Answer

The choroid plexus of the ventricles secret CSF.From the lateral ventricles,CSF flows into the third ventricle via the interventricular foramina and from the third ventricle into the fourth via the cerebral aqueduct.After exiting the fourth ventricle through the lateral and medial foramina,CSF moves into the subarachnoid space.Ultimately,CSF is absorbed through the arachnoid villi into the venous sinuses.

Question 3

Which of the following is(are)the function(s)of the cerebrospinal fluid (CSF)system?

Accepted Answer

The CSF system works to regulate the extracellular milieu by supplying water,amino acids,and specific ions to the extracellular fluid.In addition,the buoyancy provided by the CSF provides protects the brain by absorbing some of the impact when the head is struck.

Question 4

Which of the following generally carries the most promising prognosis for recovery?

Accepted Answer

Lacunar infarctions occur as a result of obstructions in small,deep arteries.Signs of lacunar infarctions develop slowly,and good recovery is common.Conversely,infarctions caused by thrombic ischemia may have an abrupt or slower onset,and residual disability is common.Both basilar artery occlusion and subdural hematoma often result in slow recovery,disability,or even death.

Question 5

Autoregulation of cerebral blood flow occurs via which of the following mechanisms?

Accepted Answer

Cerebral arteries regulate blood flow based on blood pressure,metabolites,and pH.Vasodilation occurs if the blood pressure or the O₂ or pH levels are low or if the CO₂ or lactic acid levels are elevated.Conversely,vasoconstriction occurs if the blood pressure or the O₂ or pH levels are high or if the CO₂ or lactic acid levels are low.

Question 6

Partial occlusion of the basilar artery may cause:

Accepted Answer

Partial occlusion of the basilar artery can result in tetraplegia,loss of sensation,coma,and cranial nerve dysfunction.Severe occlusion can result in locked-in syndrome or death.

Question 7

Which of the following statements is correct?

Accepted Answer

The three meningeal layers are the (1)dura mater, (2)arachnoid,and (3)pia mater.The outer layer of the dura mater is attached to the skull,with the inner layer loosely attached to the delicate arachnoid.The innermost layer,the pia mater,is tightly attached to the surface of the brain and spinal cord.Arachnoid trabeculae connect the arachnoid and pia mater.

Question 8

A patient has recently suffered a cerebrovascular accident and demonstrates left-sided hemiplegia with the leg more severely affected than the arm.The most likely location of this patient's infarction is which one of the following arteries?

Accepted Answer

Occlusion of the anterior cerebral artery results in contralateral hemiplegia and hemisensory loss.These deficits are more severe in the lower limb than in the face and upper extremity because the medial sensorimotor cortex and adjacent white matter are affected.Because neurons regulating movement and sensation in the upper limb and face are more laterally located in the cerebral cortex,occlusion of the middle cerebral artery usually produces greater deficits in the upper limb and face.

Question 9

Vertebrobasilar artery ischemia is associated with:

Accepted Answer

The most common signs of vertebrobasilar artery ischemia are gait and limb ataxia,limb weakness,oculomotor palsies,and oropharyngeal dysfunction.Other frequent signs and symptoms are loss of vision,double vision,numbness,dizziness,vertigo,headache,and vomiting.

Question 10

Which of the following processes form CSF?

Accepted Answer

Extracellular fluid leaking into the ventricles produces some CSF.However,blood filtration and the active and facilitated transport of specific substances produce most CSF.

Question 11

What structure is above the body of the lateral ventricle?

Accepted Answer

The lateral ventricles are formed by the caudate nucleus laterally,with the tail of the caudate above the inferior horn.Below the lateral ventricle is the thalamus and above is the corpus callosum.

Question 12

An embolus in which of the following arteries will usually produce cerebellar ischemia?

Accepted Answer

An embolus in an intracranial vertebral artery usually results in cerebellar infarction.

Question 13

A nonresponsive 25-year-old man is being evaluated.He collapsed several hours after being struck in the head during a bar fight.This individual has most likely suffered from which of the following?

Accepted Answer

An epidural hematoma occurs as a result of arterial bleeding between the skull and dura matter.This bleeding usually occurs when the middle meningeal artery is torn by a fracture of the temporal and/or parietal bone.As a result of rapid arterial bleeding,signs and symptoms develop swiftly-usually within several hours.In contrast,signs and symptoms of subdural hematoma develop over days or months because of low pressure venous bleeding.Subarachnoid hemorrhage usually produces a sudden excruciating headache accompanied by a brief loss of consciousness.

Question 14

Acute cerebellar infarction typically produces which of the following?

Accepted Answer

The most common symptoms of acute cerebellar infarction are dizziness and/or vertigo,an inability to sit upright without support,difficulty walking,nausea and vomiting,dysarthria,and headache.

Question 15

Where is CSF normally found?

Accepted Answer

CSF flows from the lateral ventricles into the third ventricle via the interventricular foramina and then into the fourth ventricle via the cerebral aqueduct.After exiting the fourth ventricle,CSF enters the subarachnoid space,where it flows around the brain and spinal cord.

Question 16

Occlusion of the middle cerebral artery and ischemia of the inferior parietofrontal lobes of the right hemisphere may result in which of the following?

Accepted Answer

Occlusion of the middle cerebral artery may damage the optic radiation and portions of the sensorimotor cortex.In the right hemisphere,this damage often results in a difficulty understanding spatial relationships,neglect,and impairment of nonverbal communications.

Question 17

Which of the following events occurs with prolonged cerebral edema?

Accepted Answer

In cerebral edema,fluid leaks from damaged capillaries and accumulates in the brain.This increased fluid pressure often results in ischemia,which causes the arterioles to dilate,increasing the capillary pressure and producing further edema.A lack of O₂ also makes the capillaries more permeable,allowing more fluid to escape into the extracellular compartment.

Question 18

Sparing of language,spatial awareness,and declarative memory is typical of which of the following?

Accepted Answer

Because the cranium cannot expand in older children and adults,excessive pressure in the ventricles as a result of hydrocephalus compresses the nervous tissue.This compression commonly causes gait and balance impairments,incontinence,headaches,and confusion;however,spatial language,spatial awareness,and declarative memory are spared.

Question 19

Venous blood that accumulates in the dural sinus will drain into which of the following?

Accepted Answer

Venous blood from the cerebral veins drains into the dural sinuses and eventually into the internal jugular vein.

Question 20

Which of the following stimulate vasoconstriction of the cerebral arteries?

Accepted Answer

Cerebral arteries regulate blood flow that is based primarily on blood pressure and metabolites.Vasodilation will occur if the blood pressure or the O₂ or pH levels are too low or if the CO₂ or lactic acid levels are excessive.Conversely,vasoconstriction will occur when the blood pressure or the O₂,or pH levels are excessive or if the CO₂ or lactic acid levels are too low.

Quiz 19: Support Systems: Blood Supply and Cerebrospinal Fluid System