PMC:6194691 / 3186-6003
Annnotations
{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/6194691","sourcedb":"PMC","sourceid":"6194691","source_url":"https://www.ncbi.nlm.nih.gov/pmc/6194691","text":"The brain is effectively a greatly distorted blind-ended tube. The four ventricles (see Fig. 1) form the inside of the tube and the brain parenchyma, comprised of brain cells and the interstitial spaces between them, makes up the wall. The tube is surrounded by the subarachnoid spaces, which in this discussion are taken to include the basal cisterns. Both ventricles and subarachnoid spaces are filled with cerebrospinal fluid (CSF). The inside of the tube at the IVth ventricle is connected to the outside of the tube at the cisterna magna via the foramina of Magendie and Luschka. The subarachnoid spaces are bounded on their outside by the outer meninges composed of the arachnoid and the dura (see Fig. 2 inset), which are in turn encased by the skull (see [1]). On their inside the subarachnoid spaces are separated from the brain parenchyma by a cell layer, the pia mater or inner meninges, and one or more layers of astrocyte endfeet, the glia limitans. The surfaces of the parenchyma adjacent to the ventricles are covered by a layer of cells, the ependyma (see Fig. 2 inset).\nFig. 1 Mid-saggital section of the brain showing locations of the ventricles, cerebral aqueduct, subarachnoid spaces (including the basal cisterns) and choroid plexuses. The choroid plexuses are discrete epithelial structures located in the cerebral ventricles that secrete cerebrospinal fluid (CSF) shown in pale blue, which fills the ventricles and subarachnoid spaces. Normally there is net flow of CSF from the ventricles into the cisterna magna and from there to the other subarachnoid spaces of the brain and spinal cord. Reproduced but relabelled with permission from Strazielle et al. [20]\nFig. 2 Schematic diagrams of the lateral surface of the brain showing a the arterial supply and b the venous drainage with an inset indicating the relations of the pia, the ependyma and the perivascular spaces to the brain parenchyma. The large vessels run parallel to the surfaces of the brain, with smaller branches that penetrate into the parenchyma more or less perpendicular to the surfaces (see inset). Points of penetration of the vessels down into the parenchyma are indicated by black dots at the end of vessels. Branching of arteries continues within the parenchyma yielding arterioles and eventually capillaries that then join forming venules and then veins. These merge and drain into the large veins and venous sinuses on the surface. As discussed in the text blood vessels within the parenchyma have associated perivascular spaces that provide preferential routes for materials to enter and leave the parenchyma. Figure drawn by Robert G. Thorne and used with permission. See [639] for a succinct but still thorough description of human anatomy relevant to delivery of substances to the brain and their removal from it","divisions":[{"label":"figure","span":{"begin":1087,"end":1684}},{"label":"label","span":{"begin":1087,"end":1093}},{"label":"caption","span":{"begin":1094,"end":1684}},{"label":"p","span":{"begin":1094,"end":1684}},{"label":"label","span":{"begin":1685,"end":1691}}],"tracks":[{"project":"MyTest","denotations":[{"id":"30340614-28552391-30705835","span":{"begin":764,"end":765},"obj":"28552391"},{"id":"30340614-23298398-30705836","span":{"begin":1681,"end":1683},"obj":"23298398"}],"namespaces":[{"prefix":"_base","uri":"https://www.uniprot.org/uniprot/testbase"},{"prefix":"UniProtKB","uri":"https://www.uniprot.org/uniprot/"},{"prefix":"uniprot","uri":"https://www.uniprot.org/uniprotkb/"}],"attributes":[{"subj":"30340614-28552391-30705835","pred":"source","obj":"MyTest"},{"subj":"30340614-23298398-30705836","pred":"source","obj":"MyTest"}]},{"project":"2_test","denotations":[{"id":"30340614-28552391-30705835","span":{"begin":764,"end":765},"obj":"28552391"},{"id":"30340614-23298398-30705836","span":{"begin":1681,"end":1683},"obj":"23298398"}],"attributes":[{"subj":"30340614-28552391-30705835","pred":"source","obj":"2_test"},{"subj":"30340614-23298398-30705836","pred":"source","obj":"2_test"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"MyTest","color":"#ece593","default":true},{"id":"2_test","color":"#cb93ec"}]}]}}