VENTRICULAR SYSTEM

Question 1

CSF

function

Answer 1

protective function

each part of the CNS contains a component of ventricular system

Question 2

CSF

production

Answer 2

produced continuously by the choroid plexus (70% of CSF)

choroid epithelial cells

lateral + third + fourth ventricles

Question 3

CSF

chroid plexus

Answer 3

glomerular tufts capillaries covered by ependymal cells

70% of production

remaining 30% = metabolic water prodution

Question 4

CSF

composition

(tonicity and pH)

Answer 4

clear fluid

isotonic with serum (290-295 mOsm/L)

pH 7,33

(in comparation with arterial blood 7,4 and venous blood 7,36)

Question 5

CSF

composition

(ions)

Answer 5

Na+: equal serum (138 mEq/L)

Cl- and Mg2+ higher than serum

K+, HCO3 -,Ca2+ and glucose lower than serum

Question 6

CSF

composition

(protein)

Answer 6

protein (including immunoglobulins)

lower in CSF than in serum

increased protein may indicate CNS tumor

Question 7

CSF

composition

(blood cells)

Answer 7

NORMAL

lymphocytes or mononuclear cells

(0-4 cells per millimeter cubic)

ABNORMAL

red blood cells

polymorphonuclear leukocytes

tumor cells

Question 8

CSF

volume

Answer 8

400-500 ml/day

ventricles + subarachnoid space contain 90-150 ml

(CSF is turned over 2-3 times per day)

Question 9

CSF

reabsortion

Answer 9

arachnoid granulations

into dural venous sinuses

Question 10

CSF

circulation

Answer 10

lateral ventricles

(interventricular foramen of Monro)

third ventricle

(cerebral aqueduct)

fourth ventricle

(foramina of Luschka + foramen of Magendie)

subarachnoid space

Question 11

SINUSES

superior sagittal sinus

Answer 11

in superior margin of falx cerebri

drains into 2 transverse sinuses → confluence of sinus → sigmoid sinuses

each sigmoid sinus exits skull as the internal jugular veins

Question 12

SINUSES

inferior sagittal sinus

Answer 12

in inferior margin of falx cerebri

terminates joining the great cerebral vein of Galen to form the straight sinus

(falx cerebri and tentorium cerebelli junction)

straight sinus drains to confluence of sinuses

Question 13

SINUSES

cavernous sinus

Answer 13

plexus of veins on the side of the sella turcica

surrounds internal carotid artery + cranial nerves III, IV, V and VI

drains to

transverse sinus (via superior petrosal sinus)

+
internal jugular vein (via inferior petrosal sinus)

Question 14

HYDROCEPHALUS

concept

Answer 14

excess volume or pressure of CSF

dilated ventricles

Question 15

HYDROCEPHALUS

noncommunicating

Answer 15

obstruction of flow within ventricles

commonly at narrow points

(foramen of Monro, cerebral aqueduct and fourth ventricle)

Question 16

HYDROCEPHALUS

communicating

Answer 16

Impaired CSF reabsorption

problems in arachnoid granulations

or

obstruction of flow in subarachnoid space

Question 17

HYDROCEPHALUS

normal pressure (chronic)

Answer 17

a form of communicating hydrocephalus

CSF pressure is normal

+

ventricles chronically dilated

dementia + apraxia gait + urinary incontinence

Question 18

HYDROCEPHALUS

ex vacuo

Answer 18

excess CSF in regions where brain tissue is lost

atrophy + stroke + surgery + trauma

dilated ventricles but normal CSF pressure

Question 19

CSF

red blood cells may be presented after …

Answer 19

traumatic spinal tap

+

subarachnoid hemorrhage

Question 20

CSF

polymorphonuclear leukocytes may be present in …

Answer 20

bacterial meningitis

Question 21

CSF

tumor cells may be present when …

Answer 21

meningeal involvement