Neyrogipofiz

Posterior gipofiz (orqa gipofiz yoki neyrogipofiz) - endokrin sistemaning bir qismi boʻlgan gipofiz bezining orqa boʻlagi.^[1] Gipofizning orqa boʻlagi oldingi boʻlak kabi bez hujayralari tutmaydi. Neyrogipofiz asosan, gipotalamusdan keluvchi aksonlar toʻplamidan iborat. Neyrogipofizning asosiy vazifasi aksonlar orqali keluvchi gipotalamus garmonlarini (oksitotsin va vazopressin) saqlash va bevosita qonga sekretsiya (ajratish) qilish hisoblanadi.^[2] Gipotalamo-neyrogipofizar tizim gipotalamus (paraventrikulyar yadro va supraoptik yadro), gipofizning orqa boʻlagi yaʼni neyrogipofiz va aksonlardan iborat tizimdir.^[2]

Tuzilishi

Neyrogipofiz, asosan, gipotalamusning supraoptik va paraventrikulyar yadrolarini hosil qiluvchi neyronlardan keluvchi aksonlar toʻplamidan iborat. Bu aksonlar neyrogipofizial gormonlar oksitotsin va vazopressinni saqlaydi va neyrogipofiz kapillarlariga chiqaradi, u yerdan garmonlar qon aylanish tizimiga kiradi. Neyrogipofizda aksonlardan tashqari, gormonlarni saqlash va chiqarishda yordam beruvchi astrositlarga oʻxshash maxsus glial hujayralar boʻlgan pituitsitlar ham mavjud.^[3]

Neyrogipofizning koʻpchilik manbalarga koʻra quyidagi qismlardan iborat:

Pars nevroza

Nervli boʻlak (pars nevroza) yoki orqa boʻlak deb ham ataladigan bu qism neyrogipofizning katta hajmini egallaydi va oksitotsin hamda vazopressinni saqlaydi. Baʼzan notoʻgʻri talqinlar bilan neyrogipofizning sinonimi sifatida qaraladi, pars nevroza Herring tanachalari va pituitsitlarni oʻz ichiga oladi.^[4]

Infundibulyar qism

Infundibulum yoki gipofiz sopi deb ham ataladigan infundibulyar qism gipotalamus va gipofiz tizimlarini bogʻlaydi.^[5]

Vazifasi

Gormon sekretsiyasi

Neyrogipofiz gipotalamusda hosil boʻlgan ikki gormonni toʻplaydi va qonga ajratadi. Bu garmonlar: oksitotsin va vazopressin. Gipotalamusda hosil boʻlgan garmonlar aksonlar orqali neyrogipofizga kelgandan soʻng Herring tanachalarida toʻplanadi va kerak vaqtda ajralishga tayyor holda neyrosekretor vezikulalarda saqlanadi.

Garmon	Sinonimlari	Simvoli	Asosiy taʼsir qiluvchi aʼzolari	Taʼsir mexanizmi	Hosil boʻlishi
Oksitotsin		OT	Bachadon, sut bezlari	Bachadonni qisqartiradi, sut ajralishini taʼminlaydi	supraoptik va paraventrikular yadrolardan
Vazopressin	Arginin vazopressin, antidiuretik garmon	VP, AVP, ADH	Buyraklar va arteriola	Buyraklarda reabsorbsiyani taʼminlaydi, qon tomirlar tonusini oshiradi	supraoptik va paraventrikular yadrolardan

Klinik ahamiyati

Vazopressinning yetarli darajada ajralmasligi qandsiz diabetga sababchi boʻladi. Bunda organizm siydikni konsentratsiyalash qobiliyatini yoʻqotadi. Kasallangan odamlar kuniga 20 litrgacha siydik ajratadi. Vazopressinning haddan tashqari sekretsiyasi "buzilgan antidiuretik gormon" (SIADH) sindromini keltirib chiqaradi.

Manbalar

↑ Embryology at unc.edu
↑ ^2,0 ^2,1 Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 10: Neural and Neuroendocrine Control of the Internal Milieu". In Sydor A, Brown RY (ed.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 246, 248–259. ISBN 9780071481274. •The hypothalamic–neurohypophyseal system secretes two peptide hormones directly into the blood, vasopressin and oxytocin. ... •The hypothalamic–pituitary–adrenal (HPA) axis. It comprises corticotropin-releasing factor (CRF), released by the hypothalamus; adrenocorticotropic hormone (ACTH), released by the anterior pituitary; and glucocorticoids, released by the adrenal cortex. •The hypothalamic–pituitary–thyroid axis consists of hypothalamic thyrotropin-releasing hormone (TRH); the anterior pituitary hormone thyroid–stimulating hormone (TSH); and the thyroid hormones T₃ and T₄. •The hypothalamic–pituitary–gonadal axis comprises hypothalamic gonadotropin–releasing hormone (GnRH), the anterior pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the gonadal steroids.
↑ Hatton, GI (September 1988). "Pituicytes, glia and control of terminal secretion" (PDF). The Journal of Experimental Biology. 139: 67–79. doi:10.1242/jeb.139.1.67. PMID 3062122.
↑ Histology image:14004loa from
↑ Median+eminence at the US National Library of Medicine Medical Subject Headings (MeSH)

[1] Embryology at unc.edu

[:0-2] 2,0 ^2,1 Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 10: Neural and Neuroendocrine Control of the Internal Milieu". In Sydor A, Brown RY (ed.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 246, 248–259. ISBN 9780071481274. •The hypothalamic–neurohypophyseal system secretes two peptide hormones directly into the blood, vasopressin and oxytocin. ... •The hypothalamic–pituitary–adrenal (HPA) axis. It comprises corticotropin-releasing factor (CRF), released by the hypothalamus; adrenocorticotropic hormone (ACTH), released by the anterior pituitary; and glucocorticoids, released by the adrenal cortex. •The hypothalamic–pituitary–thyroid axis consists of hypothalamic thyrotropin-releasing hormone (TRH); the anterior pituitary hormone thyroid–stimulating hormone (TSH); and the thyroid hormones T₃ and T₄. •The hypothalamic–pituitary–gonadal axis comprises hypothalamic gonadotropin–releasing hormone (GnRH), the anterior pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the gonadal steroids.

[3] Hatton, GI (September 1988). "Pituicytes, glia and control of terminal secretion" (PDF). The Journal of Experimental Biology. 139: 67–79. doi:10.1242/jeb.139.1.67. PMID 3062122.

[4] Histology image:14004loa from

[5] Median+eminence at the US National Library of Medicine Medical Subject Headings (MeSH)

[1]

[2]

[3]

[4]

[5]