What is a cistern?
Any opening in the subarachnoid space of the brain created by a separation of the arachnoid and pia mater. These spaces are filled with cerebrospinal fluid.
What are the layers of the skull - where is the subarachnoid space?
Name the large subarachnoid cisterns of the brain:
-- Cerebromedullary (Cisterna Magna)
Memorize the location of these 5 cisterns
Memorize the location of the other 2 cisterns:
Describe the prepontine cistern:
1. located on lateral aspects of the pons at its junction with the cerebellum, may be divided into superior and inferior portions.
Synonyms: cisterna pontocerebellaris, cisterna pontis, pontine cistern, prepontine cistern
Describe the Interpeduncular cistern
The interpeduncular cistern (basal cistern or Fossa interpeduncularis) is a wide cavity where the arachnoid extends across between the two temporal lobes.
It encloses the cerebral peduncles and the structures contained in the interpeduncular fossa, and contains the arterial circle of Willis.
Describe the Chiasmatic cistern:
In front, the cisterna interpeduncularis extends forward across the optic chiasma, forming the cistern of chiasma, chiasmatic cistern, or suprasellar cistern and on to the upper surface of the corpus callosum, for the arachnoid stretches across from one cerebral hemisphere to the other immediately beneath the free border of the falx cerebri, and thus leaves a space in which the anterior cerebral arteries are contained.
Describe the Suprasellar cistern
The normal suprasellar cistern is a five- or six-pointed, starshaped, fluid-filled structure as demonstrated by computerized axial tomography (CAT). At various levels the normal suprasellar cistern contains the major intracranial vessels and their anastomotic channels, the optic nerves, chiasm, and infundibular stalk.
Describe the ambient cistern:
1. a cistern located on the lateral aspect of the midbrain and dorsally continuous with the quadrigeminal cistern; the ambient cistern is sometimes defined as including the quadrigeminal cistern.
Describe the quadrigeminal cistern:
The cistern of great cerebral vein (quadrigeminal cistern) is a dilation of the subarachnoid space between the splenium of the corpus callosum and the superior surface of the cerebellum; it extends between the layers of the tela chorioidea of the third ventricle and contains the great cerebral vein.
Describe the Cerebromedullary cistern (cisterna magna):
The cisterna magna (or cerebellomedullary cistern) is one of three principal openings in the subarachnoid space between the arachnoid and pia mater layers of the meninges surrounding the brain. The openings are collectively referred to as cisterns. The cisterna magna is located between the cerebellum and the dorsal surface of the medulla oblongata. Cerebrospinal fluid produced in the fourth ventricle drains into the cisterna magna via the lateral apertures and median aperture.
What is the morphological substrate of the BBB?
Non - fenestrated endothelium linked by tight junctions.
Describe the basement membrane of the BBB?
Pericytes and astrocyte foot processes contribute to the function and development of the BBB
What molecules can readily cross the BBB
lipid soluble molecules
What diseases are associated with dysfunction of the BBB?
-- brain trauma
-- Biliruben encephalopathy
-- malignant brain tumors.
The thin membrane of glial cells lining the ventricles of the brain and the central canal of the spinal cord.
Where are the Circumventricular organs CVO?
Localized in the sagital plane under the ependyma of the 3rd and 4th cerebral ventricles
What are the the 7 CVO that we need to know?
-- Median eminence
-- Neurohypophysis (posterior pituitary)
-- Vascular organ of the lamina terminalis (OVLT)
-- Subfornical organ (SFO)
-- Subcommissural organ
-- Epiphysis (pineal gland)
-- Area postrema
Describe the median eminence:
Median eminence: Regulates anterior pituitary through release of neurohormones.
median eminence lies in the area roughly bounded on its posterolateral region by the cerebral peduncles, and on its anterolateral region by the optic chiasm.
Describe the Neurohypophysis:
Neurohypophysis (posterior pituitary): Releases neurohormones like oxytocin and vasopressin into the blood.
Describe the Vascular organ of the lamina terminalis:
Vascular organ of the lamina terminalis: A chemosensory area that detects peptides and other molecules.
Describe the sub-fornical organ
Subfornical organ: Important for the regulation of body fluids.
Describe the subcommissural organ:
The subcommissural organ is a gland in the brain. It is a circumventricular organ consisting of ependymal cells which secrete somatostatin.
It is named for its location relative to the posterior commissure.
It is near the aqueduct of Sylvius.
Describe the epiphysis (pineal gland):
Pineal body: Secretes melatonin and neuroactive peptides. Associated with circadian rhythms.
Describe the area postrema:
Area postrema: "Vomiting center": when a toxic substance enters the bloodstream it will get to the area postrema and may cause the animal to throw up. In this way, the animal protects itself by eliminating the toxic substance from its stomach before more harm can be done.