The lateral ventricle, together with the rest of the cavities in the brain, is part of the overall system in which the CSF circulates. They communicate with the subarachnoid space of the spinal cord. The inner surface of these cavities is lined with ependyma. Their function is to maintain an optimal range of pressure inside and outside the brain and spinal cord.
Types of ventricles of the brain
The lateral ventricle(s) are small cavities in the large brain that produce a specific cerebrospinal fluid. They are considered the largest of the ventricular system. This is a pair formation, and there is a specific topography for it.
The left lateral ventricle is traditionally called the first. The right one is second. They are symmetrical between themselves and adjacent anatomical structures, and are located below the epiphysis on the sides of the midline. In each ventricle, a body and horns are distinguished: anterior, posterior and lower. The lateral ventricles connect to the third ventricle through the foramen of Monroe.
The third ventricle is located between the areas responsible for vision. It has the shape of a ring and in its wall is the gray matter of the brain,containing autonomic ganglia. In addition to the lateral ventricles, this cavity is connected to the aqueduct of the brain.
The fourth ventricle is located between below the cerebellum. In shape, it resembles a pyramid and is more correctly called a rhomboid fossa. In addition to the cerebrospinal fluid, most of the spinal nerve nuclei are located at the bottom of this fossa.
Choroid plexuses
The lateral ventricle(s) are only partly involved in the choroid plexus. The bulk of these structures is located in the roofs of the third and fourth ventricles. They are responsible for most of the production of cerebrospinal fluid. In addition to them, this function is performed directly by the nervous tissue, as well as ependyma, which covers the inside of the ventricles of the brain.
Morphologically, the choroid plexuses are outgrowths of the pia mater, immersed in the ventricles. Outside, these protrusions are covered with cubic specific choroid epithelium.
Ependymocytes
The lateral ventricles of the brain are lined from the inside with a special tissue that can both produce CSF and absorb it. This helps to keep the optimal amount of fluid in the cavity and prevent an increase in intracranial pressure.
The cells of this epithelium have many organelles and a large nucleus. Their outer surface is covered with a large number of microvilli, they help the movement of cerebrospinal fluid, as well as its absorption. Outside the ependyma are Colmer cells, which are considered a special type of macrophages capable of moving alongbody.
Through multiple small gaps in the basement membrane of epindemocytes, blood plasma leaks into the cavity of the ventricles. Proteins produced directly by the cells of the inner epithelium of the brain cavities are added to it, and this is how the cerebrospinal fluid is obtained.
Blood-brain barrier
The body and horns of the lateral ventricles form a blood-brain or hematoliquor barrier with their internal lining. It is a collection of tissues arranged in a certain order:
- capillary endothelial cytoplasm;
- connective tissue containing macrophages;
- endothelial basement membrane;
- ependymal cells;
- basement membrane of ependyma.
Such a complex design is necessary in order to prevent metabolic products, drugs and other toxic substances from entering the cerebrospinal fluid.
Cerebrospinal fluid
The norm of the lateral ventricles is the production of half a liter of CSF per day, but only one hundred and forty milliliters of this amount constantly circulates in the subarachnoid space. Despite the fact that the basis for cerebrospinal fluid is blood plasma, they have significant differences in the amount of electrolytes and protein. The first is significantly higher, and the second is lower. In addition, a small amount of lymphocytes is normally present in the cerebrospinal fluid. CSF reabsorption occurs at the sites of vascular plexus implants.
The following CSF functions are distinguished:
- detoxification (transportation of metabolic products);
- depreciation (when walking, falling, sharp turns);
- formation of a hydrostatic shell around the elements of the nervous system;
- maintaining the constancy of the composition of fluids in the central nervous system;
- transport (transfer of hormones and some drugs).
Ventricular disease
When one lateral ventricle (or both) produce more fluid than they can absorb, a pathological condition such as hydrocephalus develops. The internal volume of the ventricles of the brain gradually increases, squeezing the brain tissue. Sometimes this leads to irreversible ischemia and necrosis.
In newborns and young children, the symptoms of this disease are the disproportionate size of the brain skull compared to the facial one, bulging of the fontanelles, the unreasonable anxiety of the child, turning into apathy. Adults complain of headache, eye pain, nausea and vomiting.
For diagnosis, neuroimaging methods are used: magnetic resonance therapy or computed tomography. Timely detection and treatment of this disease allows you to avoid a significant number of complications and maintain the possibility of normal life.
