Question 1

Which of the following best describes cerebrospinal fluid?&#10;A)Produced by choroid plexus of lateral ventricles&#10;B)Produced by arachnoid villi&#10;C)Produced by aqueduct of Sylvius&#10;D)Absorbed by fourth ventricle

Accepted Answer

Cerebrospinal fluid is produced by the choroid plexus of the lateral ventricles.

Question 2

Increased neuronal activity in the cerebral cortex is most likely to have which of the following effects on substances in the walls of feed arteries?&#10;A)Decreased adenosine levels&#10;B)Decreased glutamate levels&#10;C)Increased oxygen partial pressure&#10;D)Increased prostaglandin levels

Accepted Answer

Increased neuronal activity in the cerebral cortex is associated with increased metabolic demand and increased blood flow. This increase in blood flow is mediated by the release of vasodilator substances, such as prostaglandins, from the walls of feed arteries. Therefore, increased neuronal activity is most likely to result in increased prostaglandin levels in the walls of feed arteries.

Question 3

Cerebrospinal fluid enters the venous system primarily through which of the following structures?&#10;A)Aqueduct of Sylvius&#10;B)Arachnoidal villi&#10;C)Choroid plexus&#10;D)Epidural space&#10;E)Foramen of Magendie

Accepted Answer

Cerebrospinal fluid is reabsorbed into the venous system primarily through arachnoid villi, which are small protrusions of the arachnoid mater (a membrane that covers the brain) into the venous sinuses of the skull. This allows for the regulation of intracranial pressure and the removal of waste products from the brain. The other structures listed (including the aqueduct of Sylvius, choroid plexus, epidural space, and foramen of Magendie) are all involved in the production, circulation, or regulation of cerebrospinal fluid, but not in its reabsorption into the venous system.

Question 4

The normal cerebrospinal fluid pressure in an adult human is approximately what (in mm Hg)?&#10;A)25&#10;B)15&#10;C)5&#10;D)10

Accepted Answer

The normal cerebrospinal fluid (CSF) pressure in an adult human is approximately 10 mm Hg.

Question 5

Which of the following statements is correct?&#10;A)Uptake of glucose by the brain is not insulin dependant&#10;B)Increase in cerebral blood flow induced by CO&#8322; is mediated by an increase in hydrogen ion concentration&#10;C)Brain accounts for approximately 15% of total body metabolism and is highly oxygen dependent&#10;D)All of the above

Accepted Answer

Option A is true because the brain can transport glucose intracellularly via facilitative diffusion transporter proteins, regardless of insulin.
Option B is true because the increase in H+ concentration leads to vasodilation of cerebral blood vessels, which increases cerebral blood flow to help with CO2 removal.
Option C is true because the brain accounts for about 20% of the body's total oxygen consumption, despite only composing about 2% of the body's weight.

Question 6

A patients arterial pO&#8322; is 20 mm Hg. Which of the following neurological effects is most likely in this patient?&#10;A)Agitation and nervousness&#10;B)Normal responsiveness&#10;C)Comatose or unresponsive&#10;D)Somnolent but responsive to stimuli

Accepted Answer

A pO₂ of 20 mm Hg is severely low and indicates hypoxemia. Hypoxemia can lead to neurological effects ranging from confusion to coma. In this case, comatose or unresponsive is the most likely neurological effect.

Question 7

A 23-year-old man develops a subdural hematoma after an automobile accident. Which of the following is most likely to be increased in this patient?&#10;A)Cerebral blood flow&#10;B)Cerebrospinal fluid production&#10;C)Cerebrospinal fluid volume&#10;D)Intracranial pressure&#10;E)Intracranial venous volume

Accepted Answer

A subdural hematoma is a collection of blood between the dura mater and the arachnoid mater of the brain, which can increase intracranial pressure. Therefore, intracranial pressure is most likely to be increased in this patient. Cerebral blood flow, cerebrospinal fluid production, and cerebrospinal fluid volume may also be altered due to the injury but are not directly related to subdural hematoma formation. Intracranial venous volume is also not specifically related to subdural hematoma formation.

Question 8

The majority of strokes in the United States can be attributed to which of the following?&#10;A)Hemorrhage due to arterial rupture&#10;B)Hemorrhage due to venular trauma&#10;C)Ischemia due to systemic hypotension&#10;D)Ischemia due to thromboembolism

Accepted Answer

Ischemia due to thromboembolism (the formation of a blood clot that breaks away and travels through the bloodstream) is the most common cause of strokes in the United States, accounting for approximately 87% of all strokes. Hemorrhage due to arterial rupture is less common, causing approximately 13% of strokes. Hemorrhage due to venular trauma and ischemia due to systemic hypotension are much rarer causes of strokes.

Question 9

Which of the following best describes the total amount of cerebrospinal fluid produced each day by the choroid plexus of an adult human (in mL)?&#10;A)150&#10;B)500&#10;C)50&#10;D)300

Accepted Answer

The choroid plexus of an adult human produces about 500 mL of cerebrospinal fluid each day. This fluid circulates around the brain and spinal cord, providing protection and nourishment.

Question 10

Which of the following best describes the total volume of cerebrospinal fluid in an adult human nervous system (in mL)?&#10;A)150&#10;B)500&#10;C)50&#10;D)300

Accepted Answer

The total volume of cerebrospinal fluid in an adult human nervous system is approximately 150 mL.

Question 11

At mean arterial pressure levels between 140 mmHg and 170 mmHg, blood flow to the brain:&#10;A)Varies with level of arterial pressure&#10;B)Is constant and not dependant on pressure&#10;C)Is independent of arterial pressure&#10;D)Is inversely proportional to arterial pressure

Accepted Answer

The answer of At mean arterial pressure levels between 140...

Question 12

Which of the following best describes the major function of cerebrospinal fluid?&#10;A)A major controller of brain glucose metabolism&#10;B)Delivers nutrients to deep brain structures&#10;C)Serves a protective role by cushioning brain

Accepted Answer

The answer of Which of the following best describes the...

Question 13

An increase in pCO&#8322; from 40 mm Hg to 80 mm Hg would cause brain blood flow to do which of the following?&#10;A)Decrease by 50 percent&#10;B)Increase by 100 percent&#10;C)Increase by 50 percent&#10;D)Increase by 25 percent

Accepted Answer

The answer of An increase in pCO&#8322; from 40 mm...

Question 14

Which of the following statements best describes the anaerobic capacity of the brain?&#10;A)The brain can function well under anaerobic conditions because of its ability to use lactic acid as an energy source&#10;B)The brain has very little anaerobic capacity&#10;C)The brain can function well under anaerobic conditions until the glycogen stores are depleted&#10;D)Both A and C are correct

Accepted Answer

The answer of Which of the following statements best describes...

Deck 62: Cerebral Blood Flow, Cerebrospinal Fluid, and Brain Metabolism