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Term | embryonic/larval lymph gland | ID (Ontology) | FBbt:00001668 (Fly Anatomy) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Definition | Hematopoietic organ of the larva, located along the dorsal vessel, behind the brain. It produces the plasmatocytes, crystal cells and lamellocytes which are released at the end of the larval instar and onset of metamorphosis. It is composed of 3 pairs of bilateral lobes: an anterior primary lobe, a posterior secondary lobe and the most posterior lobe (or multiple lobes), the tertiary lobe. Each lobe is separated by pericardial cells. In the late embryo, the lymph gland consists of a single pair of lobes (primary lobes) containing around 20 cells each that flank the dorsal vessel. By the second larval instar, the lymph gland is composed of two or three new pairs of posterior lobes, and the primary lobes have increased in size to contain around 200 cells. During the first and early second larval instars, the lymph gland comprises only the hematopoietic progenitor population. The lymph gland increases in size ten-fold by the late third instar, and at this stage the progenitor cells (prohemocytes) become restricted to the medial region (medullary zone) of the primary lobe and become quiescent. The differentiated hemocytes are found in the periphery (cortical zone) of the primary lobe and these cells proliferate extensively. The posterior signaling center is a group of about 30 cells at the posterior tip of the primary lobe that secretes several signaling molecules and functions as a stem-cell niche. The secondary and tertiary lobes contain prohemocytes, and rarely a differentiated cell. Lymph glands are eliminated at metamorphosis.[ FlyBase:FBrf0031001 FlyBase:FBrf0032406 FlyBase:FBrf0074444 FlyBase:FBrf0155787 FlyBase:FBrf0162082 FlyBase:FBrf0187467 ] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Also Known As | "embryonic/larval hematopoietic organ" | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Records annotated with this term OR any of its CHILD TERMS | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Full annotation statements including this term (annotations to child terms are NOT included), and relevant FlyBase records | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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larva |__embryonic/larval circulatory system__ circulatory system | |__embryonic/larval circulatory system__| visceral mesoderm derivative_____________| multicellular structure | |__multi-tissue structure_______________| embryonic/larval lymph gland 698 rec. |__primary lobe of embryonic/larval lymph gland 188 rec. | |__cortical zone of lymph gland primary lobe(+) 66 rec. | |__intermediate zone of lymph gland primary lobe(+) | |__medullary zone of lymph gland primary lobe 32 rec. | |__posterior signaling center of lymph gland primary lobe(+) 56 rec. |__secondary lobe of embryonic/larval lymph gland 41 rec. |__tertiary lobe of embryonic/larval lymph gland 12 rec. |
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Is a |
multi-tissue structure visceral mesoderm derivative |
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Develops from | lymph gland primordium | ||
Part of | embryonic/larval circulatory system | ||
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External Crossreferences & Linkouts | |||
UBERON:6001668 |