The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord, the retina and optic nerve, and the olfactory nerve and epithelia. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and diploblasts. It is a structure composed of nervous tissue positioned along the rostral to caudal axis of the body and may have an enlarged section at the rostral end which is a brain. Only arthropods, cephalopods and vertebrates have a true brain, though precursor structures exist in onychophorans, gastropods and lancelets.
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates.
The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system, thus protecting the brain from harmful or unwanted substances in the blood. The blood–brain barrier is formed by endothelial cells of the capillary wall, astrocyte end-feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane. This system allows the passage of some small molecules by passive diffusion, as well as the selective and active transport of various nutrients, ions, organic anions, and macromolecules such as glucose and amino acids that are crucial to neural function.
In neuroanatomy, the ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain. Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is continuous with the central canal of the spinal cord from the fourth ventricle, allowing for the flow of CSF to circulate.
Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to help diagnose diseases of the central nervous system, including the brain and spine. Examples of these conditions include meningitis and subarachnoid hemorrhage. It may also be used therapeutically in some conditions. Increased intracranial pressure is a contraindication, due to risk of brain matter being compressed and pushed toward the spine. Sometimes, lumbar puncture cannot be performed safely. It is regarded as a safe procedure, but post-dural-puncture headache is a common side effect if a small atraumatic needle is not used.
Pia mater, often referred to as simply the pia, is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. Pia mater is medieval Latin meaning "tender mother". The other two meningeal membranes are the dura mater and the arachnoid mater. Both the pia and arachnoid mater are derivatives of the neural crest while the dura is derived from embryonic mesoderm. The pia mater is a thin fibrous tissue that is permeable to water and small solutes. The pia mater allows blood vessels to pass through and nourish the brain. The perivascular space between blood vessels and pia mater is proposed to be part of a pseudolymphatic system for the brain. When the pia mater becomes irritated and inflamed the result is meningitis.
The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central nervous system. The choroid plexus consists of modified ependymal cells surrounding a core of capillaries and loose connective tissue. Multiple cilia on the ependymal cells move to circulate the cerebrospinal fluid.
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. The other two meningeal layers are the arachnoid mater and the pia mater. It envelops the arachnoid mater, which is responsible for keeping in the cerebrospinal fluid. It is derived primarily from the neural crest cell population, with postnatal contributions of the paraxial mesoderm.
The ependyma is the thin neuroepithelial lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous system (CNS). It is involved in the production of cerebrospinal fluid (CSF), and is shown to serve as a reservoir for neuroregeneration.
The blood–testis barrier is a physical barrier between the blood vessels and the seminiferous tubules of the animal testes. The name "blood-testis barrier" is misleading as it is not a blood-organ barrier in a strict sense, but is formed between Sertoli cells of the seminiferous tubule and isolates the further developed stages of germ cells from the blood. A more correct term is the Sertoli cell barrier (SCB).
The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord. It is so named because of its resemblance to a spider web. The arachnoid mater is a derivative of the neural crest mesoectoderm in the embryo.
The central canal is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it receives cerebrospinal fluid, and shares the same ependymal lining. The central canal helps to transport nutrients to the spinal cord as well as protect it by cushioning the impact of a force when the spine is affected.
Myelography is a type of radiographic examination that uses a contrast medium to detect pathology of the spinal cord, including the location of a spinal cord injury, cysts, and tumors. Historically the procedure involved the injection of a radiocontrast agent into the cervical or lumbar spine, followed by several X-ray projections. Today, myelography has largely been replaced by the use of MRI scans, although the technique is still sometimes used under certain circumstances – though now usually in conjunction with CT rather than X-ray projections.
This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.
The glia limitans, or the glial limiting membrane, is a thin barrier of astrocyte foot processes associated with the parenchymal basal lamina surrounding the brain and spinal cord. It is the outermost layer of neural tissue, and among its responsibilities is the prevention of the over-migration of neurons and neuroglia, the supporting cells of the nervous system, into the meninges. The glia limitans also plays an important role in regulating the movement of small molecules and cells into the brain tissue by working in concert with other components of the central nervous system (CNS) such as the blood–brain barrier (BBB).
Ayub Khan Ommaya, MD, ScD (hc), FRCS, FACS was a Pakistani American neurosurgeon and the inventor of the Ommaya reservoir. The reservoir is used to provide chemotherapy directly to the tumor site for brain tumors. Ommaya was also a leading expert in traumatic brain injuries.
Leptomeningeal cancer is a rare complication of cancer in which the disease spreads from the original tumor site to the meninges surrounding the brain and spinal cord. This leads to an inflammatory response, hence the alternative names neoplastic meningitis (NM), malignant meningitis, or carcinomatous meningitis. The term leptomeningeal describes the thin meninges, the arachnoid and the pia mater, between which the cerebrospinal fluid is located. The disorder was originally reported by Eberth in 1870. It is also known as leptomeningeal carcinomatosis, leptomeningeal disease (LMD), leptomeningeal metastasis, meningeal metastasis and meningeal carcinomatosis.
A central nervous system cyst is a type of cyst that presents and affects part of the central nervous system (CNS). They are usually benign and filled with either cerebrospinal fluid, blood, or tumor cells. CNS cysts are classified into two categories: cysts that originate from non-central nervous system tissue, migrate to, and form on a portion of the CNS, and cysts that originate within central nervous system tissue itself. Within these two categories, there are many types of CNS cysts that have been identified from previous studies.
The blood–spinal cord barrier (BSCB) is a semipermeable anatomical interface that consists of the specialized small blood vessels that surround the spinal cord. While similar to the blood–brain barrier in function and morphology, it is physiologically independent and has several distinct characteristics. The BSCB is involved in many disorders affecting the central nervous system, including neurodegenerative diseases, pain disorders, and traumatic spinal cord injury. In conjunction with the blood–brain barrier, the BSCB contributes to the difficulty in delivering drugs to the central nervous system, which makes drug targeting of the BSCB an important goal in pharmaceutical research.
The blood–saliva barrier (BSB) is a biological barrier that consists of the epithelial cell layers of the oral mucosa and salivary glands, and provides physiological separation between blood vessels and the saliva in the oral cavity. In Russian academic literature the barrier is usually called the hematosalivary or hematosalivarian barrier.
