Hematopoetiska celler

Hematopoes är utvecklingen av blodkroppar.^[1] Detta inkluderar:

Alla blodceller utvecklas från multipotenta hematopoetiska stamceller i benmärgen. Stamcellerna utgör ca. 0,05% av cellerna i benmärgen, men det finns många andra celler som är viktiga för hematopoesen genom att bistå med en lämplig mikromiljö. Det bildas ca. 10^12 celler/dygn i benmärgen för att ersätta blodceller som kasseras. För att bibehålla nivån av stamceller så bildas en progenitorcell och en stamcell vid varje stamcellsdelning. För att ytterligare skydda stamcellerna är upp till 95% i inaktiv form och är på så sätt mindre utsatta för genskador.

En vilande hematopoetisk stamcell aktiveras av stamcellsfaktor (SCF), en cytokin som bildas av inkringliggande stromaceller. SCF binder till c-kit och leder till proliferation och differentiering av stamcellerna. Tidigt i hematopoesen sker differentiering till antingen en lymfoid progenitorcell eller en myeloid progenitorcell. Dessa fortsätter sedan att differentieras i ett samspel med linjespecifika cytokiner.

• Hematopoetisk stamcell
  • Lymfoid progenitorcell
  • Myeloid progenitorcell
    • Megakarocyt - SCF, trombopoetin (TPO), IL-3, Granulocyt M

      The combination of two Greek words, haima meaning blood and poiēsis meaning to produce something, forms the word hematopoiesis. So, hematopoiesis means forming blood cells (WBCs, RBCs, and platelets). 

      Hematopoiesis begins in the embryonic stage and continues through adulthood to restore blood cells. It requires a multipotent hematopoietic stem cell to divide into progenitor cells. These progenitor cells can divide into specialized cells, forming mature white blood cells (WBCs), red blood cells (RBCs), and platelets.

      Hematopoiesis, a cornerstone of our bodily functions, is a continuous process that tirelessly produces blood cells. Its significance lies in its role in ensuring the proper functioning of our immune system and the efficient transport of oxygen, making it a process we should truly appreciate. 

      The location of hematopoiesis changes throughout life. It begins in the yolk sac and aorta-gonad-mesonephros. Then, it transitions into the liver, spleen, and finally, the bone marrow and lymph nodes. The process continues in these locations throughout adult life except in pathological conditions, when it can return to its former sites.  

      Hematopoietic Microenvironment

      The

      Haematopoiesis

      Formation of blood cellular components

      Haematopoiesis (;^[1][2] from Ancient Greek αἷμα (haîma)&#;'blood' and ποιεῖν (poieîn)&#;'to make'; also hematopoiesis in American English, sometimes h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells.^[3] In a healthy adult human, roughly ten billion (10¹⁰) to a hundred billion (10¹¹) new blood cells are produced per day, in order to maintain steady state levels in the peripheral circulation.^{[4][5][page&#;needed]}

      Process

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      Haematopoietic stem cells (HSCs)

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      Main article: Hematopoietic stem cell

      Haematopoietic stem cells (HSCs) reside in the medulla of the bone (bone marrow) and have the unique ability to give rise to all of the different mature blood cell types and tissues.^[3] HSCs are self-renewing cells: when they differentiate, at least some of their daughter cells remain as HSCs so the pool of stem cells is not depleted.^[6] This phenomenon is called asymmetric division.^[7] The other daughters

      Hematopoiese: Saiba tudo sobre a Hemopoese!

      A hematopoiese (ou hemopoese) é processo pelo qual são formadas as células do sangue. Ela abrange todos os fenômenos relacionados com a origem, a multiplicação e a maturação de células primordiais ou precursoras das células sanguíneas.

      A porção celular do sangue é composta de eritrócitos, leucócitos e plaquetas. Essas três linhagens celulares, apesar de serem distintas umas das outras, são oriundas de uma célula-mãe única, denominada célula pluripotente, toipotente, stem–cell ou célula-tronco.

      Hematopoiese no Período Intra-Uterino

      As primeiras células sanguíneas do ser humano surgem no período embrionário (pré-hepático), por volta da sétima ou oitava semana de vida. Daí até o quarto mês, a formação das células se faz em agrupamentos de células redondas localizadas no saco vitelínico. Ocorre, nesse sítio, eritropoiese, que se desenvolve no mesoderma.

      Existem duas teorias que tentam explicar tal fato. A hipótese de endotélio-hemogenia defende a formação das células tronco hematopoiéticas a partir de células endoteliais, que perdem as características fenotípicas endoteliais e passam, progressivamente, a expressar marcadores hematop

      .