Neyroendokrin hujayra

Neyroendokrin hujayralar (neuroendocrine cells) — bu neyronal signalni (asab hujayralari yoki neyrosekretor hujayralar tomonidan ajratilgan neyrotransmitterlar (neurotransmitters) orqali) qabul qiluvchi va ushbu signal natijasida qonga xabarchi molekulalar bo'lgan gormonlarni (hormones) ajratuvchi hujayralardir. Shu tariqa, ular asab tizimi va endokrin tizim o'rtasidagi bog'liqlikni ta'minlaydi. Ushbu jarayon neyroendokrin integratsiya (neuroendocrine integration) deb ataladi.

Neyroendokrin hujayraga misol sifatida buyrak usti bezining miya qavati (adrenal medulla) (buyrak usti bezining eng ichki qismi) hujayrasini ko'rsatish mumkin. Ushbu hujayralar qonga adrenalin (epinephrine) ajratadi. Buyrak usti bezining miya qavati hujayralari avtonom asab tizimining simpatik bo'limi (sympathetic division) tomonidan boshqariladi. Bu hujayralar modifikatsiyalangan postganglionar neyronlar (postganglionic neurons) hisoblanadi. Avtonom asab tolalari markaziy asab tizimidan to'g'ridan-to'g'ri ularga boradi. Buyrak usti bezining miya qavati gormonlari, neyrotransmitterlar neyronal vezikulalarda saqlangani kabi, maxsus pufakchalarda (vesicles) saqlanadi. Gormonal ta'sirlar neyrotransmitterlarning ta'siriga qaraganda o'n baravar uzoqroq davom etishi mumkin.^{[manba kerak]} Simpatik nerv tolasi impulslari buyrak usti bezining miya qavati gormonlari ajralishini rag'batlantiradi. Shu yo'l bilan avtonom asab tizimining simpatik bo'limi va miya qavati sekretsiyasi birgalikda faoliyat ko'rsatadi.

Organizmdagi neyroendokrin integratsiyaning asosiy markazi gipotalamus va gipofiz bezida joylashgan. Bu yerda gipotalamik neyrosekretor hujayralar qonga turli omillarni ajratadi. Ushbu omillarning ba'zilari (rilizing-gormonlar (releasing hormones)) gipotalamusning median eminence qismida ajralib, gipofiz gormonlari sekretsiyasini nazorat qiladi. Boshqa omillar (masalan, oksitotsin va vazopressin gormonlari) esa to'g'ridan-to'g'ri qonga chiqariladi.

APUD hujayralari ham neyroendokrin tizimning bir qismi hisoblanadi. Ular neyroendokrin hujayralar bilan ko'plab o'xshash bo'yalish xususiyatlariga ega.

Asosiy neyroendokrin tizimlar

O'pka neyroendokrin hujayralari

O'pka neyroendokrin hujayralari (pulmonary neuroendocrine cells — PNECs) — bu o'pkada yakka hujayralar yoki neyroepitelial tanachalar (neuroepithelial bodies — NEBs) deb ataladigan klasterlar holatida uchraydigan ixtisoslashgan nafas yo'li epitelial hujayralaridir (epithelial cells). O'pka neyroendokrin hujayralari, shuningdek, bronxial Kulchitskiy hujayralari (Kulchitsky cells) sifatida ham tanilgan.^[2] Ular yuqori va pastki nafas yo'llarining nafas olish epiteliysida (respiratory epithelium) joylashgan. PNEC va NEBlar homila va chaqaloqlik davridanoq o'pka nafas yo'llarida mavjud bo'ladi.

Bu hujayralar butilka yoki kolba ko'rinishidagi shaklga ega bo'lib, bazal membranadan (basement membrane) to bo'shliqqa (lumen) qadar cho'zilgan. Ularni bioaktiv aminlar va peptidlar tarkibi bo'yicha ajratish mumkin. Bularga, xususan, serotonin, kaltsitonin, kaltsitonin geni bilan bog'liq peptid (CGRP), xromogranin A, gastrin ajratuvchi peptid (GRP) va xolesistokinin kiradi.

Ushbu hujayralar o'pka saratonining bir necha turlari, ayniqsa o'pkaning mayda hujayrali karsinomasi va bronxial karsinoid o'simta manbai bo'lishi mumkin.^[3]^[4]

Funksiyasi

PNEClar gipoksiyani (hypoxia) aniqlashda xemoretseptorlar bilan birga muhim ahamiyatga ega bo'lishi mumkin. Bu nazariya quyonning lümenal membranasida kislorod sensorli oqsili bilan bog'langan, kislorodga sezgir kaliy kanalining mavjudligi bilan tasdiqlanadi. Taxminlarga ko'ra, ular parakrin mexanizm (paracrine mechanism) orqali mahalliy epitelial hujayralarning o'sishi va regeneratsiyasini tartibga solishda ishtirok etadi. Bunda ularning signal beruvchi peptidlari atrof-muhitga ajraladi. Bundan tashqari, ular bazal sitoplazmadan ajralib chiqadigan neyroaktiv moddalarni saqlaydi. Ushbu moddalar chuqur lamina propria qavatidagi avtonom asab tugunlari yoki qon tomirlariga ta'sir ko'rsatadi.

Homila o'pkasidagi roli

Homila o'pkasida ular ko'pincha nafas yo'llari naychalarining shoxlanish nuqtalarida joylashgan bo'lib, insonlarda homiladorlikning 10-haftasiga kelib paydo bo'ladi. PNEC tomonidan ajratilgan peptidlar va aminlar homila o'pkasining normal rivojlanishida, jumladan shoxlanish morfogenezida ishtirok etadi. Eng yaxshi o'rganilgan peptidlar GRP (bombezinning sutemizuvchilardagi shakli) va CGRP hisoblanadi. Ushbu moddalar epitelial hujayralarga bevosita mitogen ta'sir ko'rsatadi va o'sish omillariga o'xshash ko'plab xususiyatlarni namoyon etadi.

Misol

Neyroendokrin hujayralarning ixtisoslashgan guruhlarini miyadagi uchinchi qorincha asosi (gipotalamus deb ataladigan hudud)da uchratish mumkin. Bu soha ko'pgina oldingi gipofiz hujayralarini nazorat qiladi. Shu orqali u butun tana funksiyalarini, masalan, stress, sovuq, uyqu va reproduktiv tizim reaktsiyalarini tartibga soladi. Neyronlar gipofiz oyog'iga (pituitary stalk) tutashgan hududga o'simtalar yuboradi va qon oqimiga rilizing-gormonlar chiqariladi. Ushbu gormonlar portal tomirlar orqali gipofiz hujayralariga yetkaziladi va u yerda ma'lum turdagi hujayralarning faoliyatini rag'batlantirishi, susaytirishi yoki ushlab turishi mumkin.

Yana qarang

Melanotrof

Xromofil

Oksifil hujayra (patologiya)

Oksifil hujayra (paratiroid)

Gipofiz

Manbalar

↑ ^1,0 ^1,1 ^1,2 ^1,3 „Chapter 10: Neural and Neuroendocrine Control of the Internal Milieu“, Molecular Neuropharmacology: A Foundation for Clinical Neuroscience, 2nd Sydor A, Brown RY: , New York: McGraw-Hill Medical, 2009 — 246, 248–259-bet. 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.“
↑ Addis, B. J. (1995). "Neuroendocrine differentiation in lung carcinoma". Thorax 50 (2): 113–115. doi:10.1136/thx.50.2.113. PMID 7701446. PMC 473889. https://archive.org/details/sim_thorax_1995-02_50_2/page/112.
↑ "Neuroendocrine tumors of the lung: clinical, pathologic, and imaging findings". Radiographics 26 (1): 41–57; discussion 57–8. 2006. doi:10.1148/rg.261055057. PMID 16418242.
↑ Becker, KL; Silva, OL (July 1981). "Hypothesis: the bronchial Kulchitsky (K) cell as a source of humoral biologic activity.". Medical Hypotheses 7 (7): 943–9. doi:10.1016/0306-9877(81)90049-9. PMID 6270516. https://archive.org/details/medical-hypotheses_1981-07_7_7/page/943.

Havolalar

Vikiomborda „Neuroendocrine cells“ mavzusi boʻyicha mediafayllar bor.

[NHM-Neuroendocrine_systems2-1] 1,0 ^1,1 ^1,2 ^1,3 „Chapter 10: Neural and Neuroendocrine Control of the Internal Milieu“, Molecular Neuropharmacology: A Foundation for Clinical Neuroscience, 2nd Sydor A, Brown RY: , New York: McGraw-Hill Medical, 2009 — 246, 248–259-bet. 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.“

[French2-2] Addis, B. J. (1995). "Neuroendocrine differentiation in lung carcinoma". Thorax 50 (2): 113–115. doi:10.1136/thx.50.2.113. PMID 7701446. PMC 473889. https://archive.org/details/sim_thorax_1995-02_50_2/page/112.

[3] "Neuroendocrine tumors of the lung: clinical, pathologic, and imaging findings". Radiographics 26 (1): 41–57; discussion 57–8. 2006. doi:10.1148/rg.261055057. PMID 16418242.

[Becker2-4] Becker, KL; Silva, OL (July 1981). "Hypothesis: the bronchial Kulchitsky (K) cell as a source of humoral biologic activity.". Medical Hypotheses 7 (7): 943–9. doi:10.1016/0306-9877(81)90049-9. PMID 6270516. https://archive.org/details/medical-hypotheses_1981-07_7_7/page/943.

[1]

[2]

[3]

[4]