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# Le giunzioni delle [[Tessuto endoteliale|cellule endoteliali]] vengono riorganizzate e il vaso doppio strato viene forato per consentire ai [[Fattore di crescita dell'endotelio vascolare|fattori di crescita]] e alle cellule di penetrare nel lume<ref name="wiley"/>.

# Un nucleo si forma tra i due nuovi vasi nella zona di contatto, che è piena di [[pericita|periciti]] e [[miofibroblasto|miofibroblasti]]. Queste cellule iniziano a depositare fibre di [[collagene]] nel nucleo in modo da fornire una [[matrice extracellulare]] per la crescita del lume del vaso.

# <u>'''Il nucleo è integrato senza alterazioni alla struttura di base'''</u>. L'intussuscezione è importante in quanto si tratta di una riorganizzazione di cellule già esistenti. Permette un notevole aumento del numero di capillari senza un corrispondente aumento del numero di cellule endoteliali. Questo è particolarmente importante nello sviluppo [[embrione|embrionale]], comein quanto non civi sono abbastanza risorse per creare ununa microcircolo<u>'''ricca riccomicrovascolarizzazione dipartendo celluleda nuove cellule, per ogni voltanuovi chevaso unasanguigno nuovache navesi sviluppaforma.'''</u>

Intussusception, also known as '''splitting angiogenesis''', was first observed in neonatal rats. In this type of vessel formation, the [[capillary]] wall extends into the [[lumen]] to split a single vessel in two. There are four phases of intussusceptive angiogenesis. First, the two opposing capillary walls establish a zone of contact. Second, the [[endothelial cell]] junctions are reorganized and the vessel bilayer is perforated to allow growth factors and cells to penetrate into the lumen. Third, a core is formed between the two new vessels at the zone of contact that is filled with [[pericyte]]s and [[myofibroblasts]]. These cells begin laying [[collagen]] fibers into the core to provide an [[extracellular matrix]] for growth of the vessel lumen. Finally, the core is fleshed out with no alterations to the basic structure. Intussusception is important because it is a reorganization of existing cells. It allows a vast increase in the number of [[capillaries]] without a corresponding increase in the number of [[endothelial cell]]s. This is especially important in embryonic development as there are not enough resources to create a rich microvasculature with new cells every time a new vessel develops.

Intussusception, also known as '''splitting angiogenesis''', was first observed in neonatal rats. In this type of vessel formation, the [[capillary]] wall extends into the [[lumen]] to split a single vessel in two. There are four phases of intussusceptive angiogenesis. First, the two opposing capillary walls establish a zone of contact. Second, the [[endothelial cell]] junctions are reorganized and the vessel bilayer is perforated to allow growth factors and cells to penetrate into the lumen. Third, a core is formed between the two new vessels at the zone of contact that is filled with [[pericyte]]s and [[myofibroblasts]]. These cells begin laying [[collagen]] fibers into the core to provide an [[extracellular matrix]] for growth of the vessel lumen.

Finally, the core is fleshed out with no alterations to the basic structure. Intussusception is important because it is a reorganization of existing cells. It allows a vast increase in the number of [[capillaries]] without a corresponding increase in the number of [[endothelial cell]]s. This is especially important in embryonic development as there are not enough resources to create a rich microvasculature with new cells every time a new vessel develops.

==Note==