- Subfornical organ
Infobox Brain
Name = PAGENAME
Latin = organum subfornicale
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Caption = Mesal aspect of a brain sectioned in the median sagittal plane. (Subfornical organ not labeled, but fornix and foramen of Monro are both labeled near the center.)
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BrainInfoType = hier
BrainInfoNumber = 437
MeshName = Subfornical+Organ
MeshNumber = A08.713.840
DorlandsPre = o_06
DorlandsSuf = 12596286
The subfornical organ, situated on the ventral surface of the fornix, at theforamen of Monro , is one of thecircumventricular organs of thebrain .Relations with other circumventricular organs
Other circumventricular organs are the
area postrema in the brainstem and theorganum vasculosum of the lamina terminalis (OVLT).The OVLT and the SFO are both strongly interconnected with the
nucleus medianus , and together these three structures comprise the so called "AV3V" region - the region anterior and ventral to thethird ventricle . The AV3V region is very important in the regulation offluid and electrolyte balance , by controllingthirst ,sodium excretion ,blood volume regulation , andvasopressin secretion.The SFO is outside the
blood-brain barrier , and so neurons in this region can respond to factors that are present in the systemic circulation.Receptors
Some neurons in the SFO are
osmoreceptor s, being sensitive to theosmotic pressure of the blood. These neurons project to thesupraoptic nucleus andparaventricular nucleus to regulate the activity ofvasopressin -secreting neurons. These neurons also project to thenucleus medianus (also called the median preoptic nucleus) which is involved in controllingthirst . Thus, The subfornical organ is involved influid balance .In addition, neurons in the SFO have receptors for many hormones that circulate in the blood but which do not cross the blood-brain barrier, including
angiotensin [cite journal |author=Lind R, Johnson A |title=Subfornical organ-median preoptic connections and drinking and pressor responses to angiotensin II |journal=J Neurosci |volume=2 |issue=8 |pages=1043–51 |year=1982 |pmid=7108583] ,atrial natriuretic hormone ,endothelin andrelaxin .References
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