Cerebrospinal FluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at... (CSF), is a clear, colourless liquid that fills and surrounds the brain and
the spinal cordThe main nerve trunk running down the spinal canal and connecting the individual’s mind and consciousness to the rest of his or her body. It is about the size of a person’s little finger, in diameter. It cannot repair itself if damaged. and provides a mechanical barrier against shock. Formed primarily in the
ventriclesThe brain is not an entirely solid organ. There are chambers within the brain, referred to as ventricles or, more correctly, cerebral ventricles, to distinguish them from the ventricles of the heart. They represent the remnants of the central canal of the developing central nervous system, although they have taken on a much more complex shape than the original embryonic structure. There are four in total, one each side of the midline (referred to as the lateral ventricles) and two more, in the midline, referred to as the third and fourth ventricles, albeit often using Roman numerals. of the brain, the cerebrospinal fluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at... supports the brain and provides lubrication
between surrounding bones and the brain and spinal cordThe main nerve trunk running down the spinal canal and connecting the individual’s mind and consciousness to the rest of his or her body. It is about the size of a person’s little finger, in diameter. It cannot repair itself if damaged.. When an individual suffers a
head injury, the fluid acts as a cushion, dulling the force by distributing its impact. The fluid
helps to maintain pressure within the cranium at a constant level. An increase in the volume
of blood or brain tissueIn everyday speech a piece of tissue is a thin sheet of paper, used to wrap a present or, in a slightly different form, to blow the nose, or to be used in the toilet. In biology the word tissue refers to living material made up of cells or groups of cells of similar type or types. We may speak, for example, of nerve tissue or of fatty tissue, of glandular tissue or of connective tissue. Individual organs of the body, such as the brain, the heart, the liver or the kidneys, are made up of several tissue types, almost always including connective tissue. results in a corresponding decrease in the fluid. Conversely, if there
is a decrease in the volume of matter within the cranium, as occurs in atrophyThis is a process when one of the body organs, or part of it, physically wastes away. This usually results from that body part being deprived of its blood supply. Atrophy is different from hypoplasia. of the brain,
the CSF compensates with an increase in volume. The fluid also transports metabolic waste
products, antibodies, chemicals, and pathological products of disease away from the brain
and spinal-cord tissueIn everyday speech a piece of tissue is a thin sheet of paper, used to wrap a present or, in a slightly different form, to blow the nose, or to be used in the toilet. In biology the word tissue refers to living material made up of cells or groups of cells of similar type or types. We may speak, for example, of nerve tissue or of fatty tissue, of glandular tissue or of connective tissue. Individual organs of the body, such as the brain, the heart, the liver or the kidneys, are made up of several tissue types, almost always including connective tissue. into the bloodstream. CSF is slightly alkaline and is about 99 percent
water. There are about 100 to 150 ml of CSF in the normal adult human body.
The exact method of the formation of the CSF is uncertain. After originating in the ventriclesThe brain is not an entirely solid organ. There are chambers within the brain, referred to as ventricles or, more correctly, cerebral ventricles, to distinguish them from the ventricles of the heart. They represent the remnants of the central canal of the developing central nervous system, although they have taken on a much more complex shape than the original embryonic structure. There are four in total, one each side of the midline (referred to as the lateral ventricles) and two more, in the midline, referred to as the third and fourth ventricles, albeit often using Roman numerals.
of the brain, it is probably filtered through the nervous-system membranes (ependymaA single layer of cells that line the ventricles of the brain and the central canal of the spinal cord.). The
CSF is continually produced, and all of it is replaced every six to eight hours. The fluid is
eventually absorbed into the veins; it leaves the cerebrospinal spaces in a variety of
locations, including spaces around the spinal roots and the cranial nervesTwelve pairs of nerves (for the right and left sides of the body) that pass directly from the brain to carry signals directly to and from the body, as opposed to signals which pass to and from the brain via the spinal cord. A neurological examination record will often include a phrase starting with “cranial nerve examination revealed . . . .”.. Movement of the
CSF is affected by the downward pull of gravity, the continual process of secretion and
absorption, blood pulsations in contingent tissueIn everyday speech a piece of tissue is a thin sheet of paper, used to wrap a present or, in a slightly different form, to blow the nose, or to be used in the toilet. In biology the word tissue refers to living material made up of cells or groups of cells of similar type or types. We may speak, for example, of nerve tissue or of fatty tissue, of glandular tissue or of connective tissue. Individual organs of the body, such as the brain, the heart, the liver or the kidneys, are made up of several tissue types, almost always including connective tissue., respiration, pressure from the veins, and
head and body movements.
Examination of the CSF may diagnose a number of diseases. A fluid sample is obtained by
inserting a needle into the lumbarThe small of the back, below the ribcage or, in neurological practice, the spine in this region. region of the lower back below the termination of the
spinal cordThe main nerve trunk running down the spinal canal and connecting the individual’s mind and consciousness to the rest of his or her body. It is about the size of a person’s little finger, in diameter. It cannot repair itself if damaged.; this procedure is called a lumbar punctureA long needle is passed into the lower part of the spine, in order to remove some cerebrospinal fluid. This may be to reduce pressure within the head or to obtain a sample of the fluid for laboratory analysis. or spinal tap. If the CSF is cloudy,
meningitisThis word simply means that the membranes which line the inside of the skull and spinal canal have become inflamed. An outbreak of meningitis in the community will cause alarm because the cause is likely to be a virulent micro-organism that can cause serious illness or even death. Following surgery upon the brain, however, inflammation of the lining membranes can result from irritation by even small amounts blood products or muscle protein, which are inevitably “spilt” during surgery. The term chemical meningitis, or aseptic meningitis, is used to refer to this condition. It is self-limiting and not usually life- threatening but it needs to be distinguished from the more serious bacterial meningitis, which can also occasionally complicate intracranial surgery. (inflammation of the central nervous systemThe brain and spinal cord together make up the central nervous system. Nerves issue from both structures, passing out of the head and spinal canal, to supply all parts of the body, thereby allowing for voluntary movements to take place, various senses to be perceived and for the function of many internal organs to be regulated. Collectively, these nerves make up the peripheral nervous system. lining) may be present. Blood in the
fluid may indicate a haemorrhage in or around the brain.