Ventricular System

Question 1

Where is CSF produced?

Answer 1

In the choroid plexuses

Question 2

What is the function of CSF?

Answer 2

-functions as a buffer to absorb stress transferred through the rigid skull

Question 3

What is the general pathway of CSF?

Answer 3

• ventricles to the surface of the brain
• drain into the venous sinuses of the skull
• flows unidirectionally into subarachnoid space

Question 4

Pathology due to disruption of CSF circulation causes what?

Answer 4

Hydrocephalus

Question 5

Where are the lateral ventricles located?

Answer 5

In each hemisphere

Question 6

Where is the third ventricle?

Answer 6

lies in a midline slit in the dienceohalon

Question 7

Where is the fourth ventricle located?

Answer 7

Between the pons and the medulla and the cerebellum

Question 8

What serves for the communication between the lateral ventricles and the third ventricle?

Answer 8

Interventricular foramina

Question 9

What are the five parts of the lateral ventricles?

Answer 9

1. Anterior horn in the frontal lobe
2. Body in the frontal and parietal lobes
3. Posterior horn projecting back into the occipital lobe
4. Inferior horn curving down toward the temporal lobe
5. Atrium-where the body and the posterior and inferior horns meet

Question 10

what makes of the lateral wall of the third ventricle?

Answer 10

-the medial surface of the thalamus and the hypothalamus

Question 11

the third ventricle has a thin membranous roof containing what?

Answer 11

choroid plexus

Question 12

anteriorly, the third ventricle ends at what?

Answer 12

-the lamina terminalis

Question 13

posteriorly, the third ventricle ends how?

Answer 13

-it narrows to become the cerebral aqueduct (aqueduct of sylvius)

Question 14

where does the interventricular foramen lie?

Answer 14

in the anterior part of each wall of the third ventricle

Question 15

the portion of the fourth ventricle rostral to its peak is called what?

Answer 15

-medullary velum

Question 16

the portion of the fourth ventricle caudal to its peak is called what?

Answer 16

inferior medullary velum

Question 17

what is the floor of the fourth ventricle also called?

Answer 17

the rhomboid fossa

Question 18

what are the three aperatures that allow CSF to exit the ventricular system to enter the subarachnoid space?

Answer 18

• two lateral aperatures: foramen of luschka

- one median aperature: foramen magendie

Question 19

the third ventricle communicates with the fourth ventricle by what?

Answer 19

the aqueduct of sylvius

Question 20

CSF is propelled forward passively by what?

Answer 20

-the pulsations of the brain circulation

Question 21

how much CSF is within and around the brain? how much is in the ventricles?

Answer 21

• 150-200mL in the brain

- 25 mL in ventricles

Question 22

what is a choroid plexus?

Answer 22

-strands of highly convoluted and vascular membranous material

Question 23

where is the choroid plexus enlarged? what is it called?

Answer 23

• in the region of the atrium

- then called the glomus

Question 24

why can the glomus be seen in X rays?

Answer 24

it becomes calcified with age

Question 25

how is the choroid plexus formed?

Answer 25

-evagination of the ependymal layer of cells containing arterioles, capillaries, and venules

Question 26

what kind of cells are in choroid epithelium?

Answer 26

-cuboidal, secretory epithelium

Question 27

how does the choroid plexus generate CSF?

Answer 27

- by filtering blood - plasma and fluid can go through fenestrations in the capillaries, but cells cannot - there are no cells in CSF

Question 28

does CSF in the subarachnoid space penetrate through the pia mater?

Answer 28

NOOOOOOOOO

Question 29

what are arachnoid granulations?

Answer 29

small protrusions of the arachnoid through the pia mater into the venous sinuses -allows CSF to exit subarachnoid space and enter the blood stream

Question 30

where do the largest granulations lie?

Answer 30

along the superior sagittal sinus

Question 31

smaller granulations are called what?

Answer 31

villi

Question 32

arachnoid granulations act as what?

Answer 32

one-way valves

Question 33

is the rate of production of CSF independent or dependent of blood pressure and intre-ventricular pressue?

Answer 33

relatively independent

Question 34

what causes hydrocephalus?

Answer 34

-CSF pressure rises and ventricles expand - excess production of CSF - blockage of CSF circulation - deficiency in CSF reabsorption - vacuum

Question 35

what is THE MOST COMMON cause of hydrocephalus?

Answer 35

blockage of CSF circulation

Question 36

what is communicating hydrocephalus?

Answer 36

-ventricles can still communicate, so blockage is outside

Question 37

what is non-communicating hydrocephalus?

Answer 37

-blockage is within the ventricles

Question 38

what could cause a defect in reabsorption of CSF?

Answer 38

- congenital absence of arachnoid villi | - obstruction of superior sagittal sinus

Question 39

what is the triad of symptoms for increased intrcranial pressure?

Answer 39

- headache - nausea/vomiting - papilledema

Question 40

who normally experiences normal pressure hydrocephalus?

Answer 40

elderly!

Question 41

when is papilledema not seen as a symptom with increased intracranial pressure?

Answer 41

normal pressure hydrocephalus-can be intermittent

Question 42

what causes normal pressure hydrocephalus?

Answer 42

- decreased reabsorption of CSF at the arachnoid granulations - blockage is outside ventricles, so it is intermittent and not a constant condition.

Question 43

who is most likely to experience pseudotumor cerebri?

Answer 43

-obese women

Question 44

what are symptoms of pseuotumor cerebri?

Answer 44

- headache and visual disturbances - can be confused with psych issues - PAPILLEDEMA - increased ICP - CONSTANT CONDITION