CSF = Cerebrospinal Fluid - Chapter 12

blood-CSF barrier = blood - brain

A physiological mechanism that alters the permeability of brain capillaries, so that some substances, such as certain toxins and drugs, are prevented from entering brain tissue, while other substances are allowed to enter freely; physically it consists of the capillary endothelial cells and their basement membranes and the processes of astrocytes associated with the capillary beds that serve the brain and spinal cord tissue.

median aperture

A median opening permitting CSF to move from the fourth ventricle to the subarachnoid space.

lateral apertures

A pair of lateral openings permitting CSF to move from the fourth ventricle to the subarachnoid space.

hydrocephalus

A usually congenital (less often acquired, e.g., from tubercular meningitis) progressive condition in which an abnormal accumulation of cerebrospinal fluid in the cerebral ventricles causes enlargement of the skull and compression of the brain, destroying much of the neural tissue, and possibly increasing the size of the fontanelles and even the top of the head in newborns where skull bones have not united. aka water on the brain.

choroid plexus

One of the delicate fringelike processes, consisting almost entirely of blood vessels, which project into each of the four ventricles of the brain which are lined by specialized ependymal cells which secrete cerebrospinal fluid.

circumventricular organs

Several small structures located around the edges of the third and fourth ventricles, lacking the regular blood-brain barrier and thus serving as significant sites for neural-endocrine interaction.

cerebral aqueduct

The canal connecting and transporting CFS from the third to the fourth ventricle which is in the midbrain.

arachnoid villi

The finger-like projections of the arachnoid membrane which project into the cranial venous sinuses within the dura mater along the major fissures of the brain where they are near the venous blood and where cerebrospinal fluid can be transferred from the subarachnoid space back into the bloodstream.

fourth ventricle

The fourth of the ventricles of the brain, a narrow space between the pons and upper medulla oblongata anteriorly and the cerebellum posteriorly which receives CSF from the cerebral aquaduct and passes CSF on to the central canal of the spinal cord and outward into the subarachnoid space; contain a choroid plexus which secretes CSF.

lateral ventricles

The largest pair (right and left) of the ventricles of the brain which are irregular with projecting horns which are in the interior of the cerebral hemispheres; contain a choroid plexus which secretes CSF which circulates through them and passes to the third ventricle.

CSF = cerebrospinal fluid

The protein-poor serous plasma filtrate which is secreted by choroid plexus cells in each of the four ventricles of the brain and which circulates through the ventricles of the brain, the central canal of the spinal cord, and the subarachnoid space, and returns to the blood stream at the arachnoid villi; it functions as a shock absorption fluid cushion for the brain and spinal cord and as a second circulatory fluid delivering oxygen and nutrients to the nervous tissue.

(brain) ventricles

The series of four interconnecting cavities of the brain, lined by ependymal cells and with a specialized choroid plexus which produce the cerebrospinal fluid that fills these chambers.

Dural sinuses

The series of large, somewhat irregular, blood-filled venous spaces with roughly triangular cross-sections which are located within the dura mater where the dura follows the contours of the major fissures of the brain; typically there are four major dural sinuses, the superior sagittal, straight, and two transverse sinuses; these venous spaces are the locations for the arachnoid villi through which cerebrospinal fluid = CSF is reabsorbed to be returned to the venous blood supply of the brain.

subarachnoid space

The space in the meninges covering the brain and the spinal cord located beneath the arachnoid membrane and above the pia mater which contains the cerebrospinal fluid.

third ventricle

The third of the ventricles of the brain, a narrow vertical space within the thalamus of the diencephalon which receives CSF from the lateral ventricles and passes CSF on via the cerebral aquaduct to the fourth ventricle; contain a choroid plexus which secretes CSF.

interventricular foramina

The two openings or short tubes which drain the CSF from the lateral ventricles into the third ventricle.