ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Granulopoiesis

Updated on April 23, 2016

It occurs in the following stages in the bone marrow:

a)Pluripotential hemopoietic stem cell

b)Myeloblast

c)Promyelocyte

d)Eosinophil

e)Basophil

f)Neutrophil

Pluropotential hemopoietic stem cell

Also hemocytoblasts. These are stem cells that give rise to all the other blood cells through the process hematopoiesis. They are derived from mesoderm and located in the red bone marrow. They give rise to both myeloid and lymphoid lineages of blood cells.

Myeloblast

It is a unipotent stem cell, which will differentiate into one of the effectors of the granulocyte series. Unipotent stem cell; a cell that can differentiate only along one lineage. The stimulation by G-CSF and other cytokines triggers maturation, differentiation, proliferation and cell survival. It is found in the bone marrow. They are the first recognisable cells in granulopoiesis.

Myelocyte

A myelocyte is a young cell of the granulocyte series, occurring normally in bone marrow and can be found in circulating blood when infected. This stage occurs in all granulocytes. It further differentiates through a series of different stages to results into: a)Basophil b)Neutrophil c)Eosinophil Neutrophils are the only leukocytes to be divided into myelocyte, band and PMN stage.

Promyelocyte

This is a granulocyte precursor, developing from the myeloblast and developing into the myelocyte. It differentiates into a myelocyte

Neutrophil

It is staged into:

a)Neutrophilic myelocyte- The developing neutrophil can now be differentiated from basophils and eosinophils as neutrophil specific granules are now being formed.

b)Neutrophilic metamyelocyte-At this stage mitosis can no longer occur. The nucleus elongates, becomes heterochromatic and has a kidney like shape. Differentiation is now much clearer from other granulocytes as the specific granules are in a far greater number than the primary granules formed in the promyelocyte stage.

c) Band cell- As the metamyelocyte matures the nucleus becomes more attenuated and the cell is then called a “band” or “stab” form. Nucleus starts to segment.

d) Neutrophil-Mature neutrophil is formed and the nucleus is segmented and has 3 to 5 lobes. This lobular structure of the nucleus gives rise to the name polymorphonuclear neutrophil

Neutrophil Granules

Primary granules. Mostly alpha granules (azurophilic)Contain primary lysosomesMyeloperoxidase (Membrane proteins)Nitric acid synthase, cathepsins,(matrix microbiocidal) Acid-mucopolysaccharide, heparin-binding protein, (Hydrolases),BPI (bactericidal permeability increasing protein)

Secondary granules Beta granules Strong bactericidal enzymes Lactoferrin Lysozyme , gelatinase, histaminase, heparinase, Sialidase Β2-microglobulin , urokinase-type plasminogen

Basophil

Under the stimulation of GM-CSF and IL-3, the CFU-GEMM differentiates into CFU-Ba . It is staged into: a)Myeloblast & Promyelocyte-These stages are common to all granulocytes and no distinction can be made between different cell lines. b)Basophilic myelocyte & metamyelocyte-Specific granules start to appear in the myelocyte stage, and as the cell develops into the metamyelocyte stage, mitosis ceases. c)Basophil-Final nuclear shape is masked by the high density of cytoplasmic granules. ●

Basophil Granules

Protein components Histamine – binds to H1,2,3 receptors Proteoglycans;Heparin – packaging of basic proteins;Chondriotin sulphates – Packaging (into granules); Enzymes Chymase - inactivate bradykinin, activate angiotensin 1; Tryptase – cleaves C3 ;Cathepsin G-like protease inactivates bradykinin Carboxypeptidase

Others Charcot leyden crystal protein - lysophospholipase MBP Sulphatase

Eosinophil

Under the stimulation of GM-CSF, IL-3 and IL-5 the CFU-GEMM differentiates into the CFU-Eo . It is staged as:

a)Myeloblast & Promyelocyte-These stages are common to all granulocytes and no distinction can be made between different cell lines.

b)Eosinophilic myelocyte & metamyelocyte-Specific granules start to appear in the myelocyte stage and once the cell has reached the metamyelocyte stage it cannot undergo further mitosis.

c)Eosinophil-Mature cell has a bilobed nucleus. There are species specific variations in granule size once stained.

Eosinophil Granules

Primary granules Eosinophil peroxidase Mediate damage to microbes Broncho-constriction and tissue damage ;Charcot –Leyden crystal protein Inflammatory response and respiratory disease

Secondary granules (specific) Eosinophil cytotoxic;Pro-inflammatory proteins eg Major Basic Protein (MBP) release of mediators from Baso and Mast Eosinophil cationic protein (ECP) Eosinophil Derived Neurotoxin (EDN); Arylsulphatase-B

Summary

Neutrophils and monocytes (which evolve into macrophages when they enter the tissues), arise form a common committed progenitor. The myeloblast is the earliest recognizable precursor in the granulocytic series that is found in the bone marrow. On division the myeloblast gives rise to promyelocyte which contain Hematology abundant dark “azurophilic” primary granules that overlie both nucleus and cytoplasm. With subsequent cell divisions these primary granules become progressively diluted by the secondary, less conspicuous “neutrophilic” granules that are characteristic of the mature cells. This concomitant cell division and maturation sequence continues form promyelocytes to early myelocytes, late myelocytes, and they metamyelocytes, which are no longer capable of cell division.As the metamyelocyte matures the nucleus becomes more attenuated and the cell is then called a “band” or “stab” form. Subsequent segmentation of the nucleus gives rise to the mature neutrophil or polymorphonuclear leukocyte. The average interval from the initiation of granulopoiesis to the entry of the mature neutrophil into the circulation is 10 to 13 days. The mature neutrophilic remains in the circulation for only about 10 to 14 hours before entering the tissue, where it soon dies after performing its phagocytic function.

Hematopoiesis
Hematopoiesis

Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)