H14: Brain CSF

ventricle

cavities in the brain

lateral ventricles

2

Cavity located in the interior of each cerebral hemisphere; thus there

are 2 lateral ventricles.

The 2 lateral ventricles are the largest of the ventricles

both lateral ventricles are separated by septum pellucidum

Each communicates with the third ventricle by the interventricular

foramen of Monro

the lateral ventricles are the ________

largest

septum pellucidum

thin membrane that separates lateral ventricles

interventricular foramen of Monro

connects lateral ventricles to third ventricle

third ventricle

1

Narrow, located between the thalamius of each side

Communicates with the fourth ventricle by the cerebral aqueduct of Sylvius (which is

located in the midbrain)

cerebral aqueduct of sylvius

connects 3rd and 4th ventricles

fourth ventricle

1

Cavity located in the pons and medulla

Is continuous with the central canal of the medulla, which in turn, is

continuous with the central canal of the spinal cord

Opens by means of 1 median and 2 lateral aperatures into the

subarachnoid space.

These aperatures are the only means by which

the cerebral spinal fluid formed in the ventricles enters the

subarachnoid space.

fourth ventricle opening

Opens by means of 1 median and 2 lateral aperatures into the

subarachnoid space.

Aperature

an opening or hole

aperature function in fourth ventricle

These aperatures are the only means by which

the cerebral spinal fluid formed in the ventricles enters the

subarachnoid space.

fourth ventricle foramina

2 Luschka

1 Magendie

luschka foramen

2 in the fourth ventricle

lateral

magendie foramen

1 in the fourth venticle

medial

Cerebral Spinal Fluid (CSF)

a clear, colourless, acellular

fluid, similar to blood plasma

choroid plexus

certain sites in the ventricles are lined with this

(EXTRA: modified pia mater together with modified

ependymal cells)

produces CSF

functions of CSF

1.To cushion and support the brain and

spinal cord

2. As a lymphatic system

3. As an environment for neurons

what produces CSF

choroid plexus

CSF Flow SUMMARY

Lateral Ventricle -> Interventricular Foramen of Monroe -> 3rd Ventricle -> Cerebral Aqueduct of Sylvius -> 4th Ventricle -> 2 Foramen of Leuscka and Foramen of Magendie -> subarachnoid space around brain and spinal cord-> Arachnoid Granulations -> Superior Saggital Sinus -> venous system, Away from brain

CSF Flow: lateral ventricles

CSF is formed in the lateral ventricles by the choroid plexus

after it is passed to interventricular foramen of Monro to the 3rd ventricle

CSF Flow: interventricular foramen of Monro

receives CSF from lateral ventricles and brings it to 3rd ventricle

CSF Flow: 3rd ventricle

receives CSF from interventricular foramen and passes it to the cerebral aqueduct of sylvius to the 4th ventricle

CSF Flow: cerebral aqueduct of sylvius

receives CSF from 3rd ventricle and brings it to 4th ventricle

CSF Flow: 4th ventricle

receives CSF from cerebral aqueduct of sylvius and pass through the 3 apentures: foramen of luschka, foramen of magendie, foramen of luschka

CSF Flow: Foramen of luschka and magendie

receives CSF from 4th ventricle and brings it to the subarachnoid space

CSF Flow: subarachnoid space

receives CSF from foramen of luschka, foramen of magendie, foramen of luschka and it travels upward around the brain and downward around the spinal cord

the fluid circulates and eventually enters the arachnoid granulations

CSF Flow: arachnoid granulations

After subarachnoid space, the fluid circulates and eventually enters the arachnoid

granulations which are found as absorptive areas in the

arachnoid mater

after it goes to lateral lacunae

CSF Flow: lateral lacunae

from arachnoid granulations

after it goes to superior sagittal sinus

CSF Flow: superior sagittal sinus

from lateral lacunae

brings it into venous system of the body

CSF Flow: SUMMARY

Is formed in the lateral ventricles by the choroid plexus

2. Passes through the interventricular foramen of Monro

3. Joins the CSF produced in the 3rd ventricle

4. Passes through the narrow cerebral aqueduct of Sylvius

5. Joins with the CSF produced in the 4th ventricle

6. Passes through the aperatures (2 foramen of Lushka, 1 foramen of

Magendie) of the 4th ventricles into the

subarachnoid space

7. It then travels upward around the brain and downward around

the cord

8. The fluid circulates and eventually enters the arachnoid granulations,(top of brain) where CSF is reabsorbed and passes through the lateral lacunae to drain into the superior sagittal sinus and finally into the venous system of the

body

CSF FLOW DIAGRAM

narrowest part of csf pathway

cerebral aqueduct of slyvius

if stenosis occurs here, CSF will back up and could cause hydrocephalus or water on the brain