Question

Please explain what cerebral spinal fluid (CSF) is, how it is made (structures involved); and discuss its complete circulation (as explained in the lecture). You must reply to at least one student's explanation to receive credit.

Answer 1

Cerebral Spinal Fluid (CSF)

The fluid which flows in and around the hollow spaces of the brain and spinal cord, and between two of the meninges (thin layer of tissue that cover and protect the brain and spinal cord ).It is a clear and colorless body fluid.

Produced by a specialized ependymal cells in the choroid plexus of the ventricles of the brain.

CSF act as a cushion or buffer, providing basic mechanical and immunological protection to the brain inside the skull.

About 125 ml of Cerebral spinal fluid at one time and 500 ml is secreted every day.

HOW CSF IS MADE?

First Cerebral Spinal fluid is formed by Amniotic Fluid. Than once ventricle are formed, CSF is formed by Choroid plexus.

In embryo around third week of development there is a three layered disc, covered with ectoderm, mesoderm and endoderm. A tube like formation developed in the midline called the notochord.The notochord releases extracellular molecules ththat effects the transformation of the overlying ectoderm into nervous tissue. The neural tube, forming from the ectoderm, contains CSF before the development of choroid plexus due to amniotic fluid i already told you about that the first CSF is Formed by amniotic fluid.

Development of forebrain surrounds the neural cord. After the full development of forebrain the neural cord becomes a ventricle of brain and choroid plexus also develops , producing and releasing a CSF.

Structure are below

These structures are involved in made of CSF from embryonic stage to develop stage.

CIRCULATION OF CSF

1. CSF is produced by choroid plexus in each lateral ventricle.

2. CSF flow through interventricular foramina into third ventricle.

3. Choroid plexus is third ventricle add more CSF.

4. CSF flow down cerebral aqueduct to fourth ventricle.

5. Chroroid plexus in fourth ventricle add more CSF.

6. CSF flows out two lateral apertures and one median aperture.

7. CSF fills subarachnoid space and bathes external surfaces of brain and spinal cord.

8. At arachnoid granulation , CSF is reabsorbed into venous blood of rural venous sinuses.